diff --git a/.gitignore b/.gitignore
index 465e2bd..b19b893 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,3 @@
 .DS_STORE
-cover*
+coverage.out
 tmp
\ No newline at end of file
diff --git a/Makefile b/Makefile
index de31643..6dfc51f 100644
--- a/Makefile
+++ b/Makefile
@@ -14,3 +14,7 @@ install-ffmpeg:
 	cd $(srcPath) && ./configure --prefix=.. $(configure)
 	cd $(srcPath) && make
 	cd $(srcPath) && make install
+
+coverage:
+	go test -coverprofile=coverage.out
+	go tool cover -html=coverage.out
diff --git a/astiav_test.go b/astiav_test.go
index c0f11d9..d7673f3 100644
--- a/astiav_test.go
+++ b/astiav_test.go
@@ -1,4 +1,4 @@
-package astiav_test
+package astiav
 
 import (
 	"errors"
@@ -7,7 +7,6 @@ import (
 	"sync"
 	"testing"
 
-	"github.com/asticode/go-astiav"
 	"github.com/asticode/go-astikit"
 )
 
@@ -46,12 +45,12 @@ func (h *helper) close() {
 }
 
 type helperInput struct {
-	firstPkt      *astiav.Packet
-	formatContext *astiav.FormatContext
-	lastFrame     *astiav.Frame
+	firstPkt      *Packet
+	formatContext *FormatContext
+	lastFrame     *Frame
 }
 
-func (h *helper) inputFormatContext(name string) (fc *astiav.FormatContext, err error) {
+func (h *helper) inputFormatContext(name string) (fc *FormatContext, err error) {
 	h.m.Lock()
 	i, ok := h.inputs[name]
 	if ok && i.formatContext != nil {
@@ -60,7 +59,7 @@ func (h *helper) inputFormatContext(name string) (fc *astiav.FormatContext, err
 	}
 	h.m.Unlock()
 
-	if fc = astiav.AllocFormatContext(); fc == nil {
+	if fc = AllocFormatContext(); fc == nil {
 		err = errors.New("astiav_test: allocated format context is nil")
 		return
 	}
@@ -86,7 +85,7 @@ func (h *helper) inputFormatContext(name string) (fc *astiav.FormatContext, err
 	return
 }
 
-func (h *helper) inputFirstPacket(name string) (pkt *astiav.Packet, err error) {
+func (h *helper) inputFirstPacket(name string) (pkt *Packet, err error) {
 	h.m.Lock()
 	i, ok := h.inputs[name]
 	if ok && i.firstPkt != nil {
@@ -95,13 +94,13 @@ func (h *helper) inputFirstPacket(name string) (pkt *astiav.Packet, err error) {
 	}
 	h.m.Unlock()
 
-	var fc *astiav.FormatContext
+	var fc *FormatContext
 	if fc, err = h.inputFormatContext(name); err != nil {
 		err = fmt.Errorf("astiav_test: getting input format context failed")
 		return
 	}
 
-	pkt = astiav.AllocPacket()
+	pkt = AllocPacket()
 	if pkt == nil {
 		err = errors.New("astiav_test: pkt is nil")
 		return
@@ -119,7 +118,7 @@ func (h *helper) inputFirstPacket(name string) (pkt *astiav.Packet, err error) {
 	return
 }
 
-func (h *helper) inputLastFrame(name string, mediaType astiav.MediaType) (f *astiav.Frame, err error) {
+func (h *helper) inputLastFrame(name string, mediaType MediaType) (f *Frame, err error) {
 	h.m.Lock()
 	i, ok := h.inputs[name]
 	if ok && i.lastFrame != nil {
@@ -128,14 +127,14 @@ func (h *helper) inputLastFrame(name string, mediaType astiav.MediaType) (f *ast
 	}
 	h.m.Unlock()
 
-	var fc *astiav.FormatContext
+	var fc *FormatContext
 	if fc, err = h.inputFormatContext(name); err != nil {
 		err = fmt.Errorf("astiav_test: getting input format context failed: %w", err)
 		return
 	}
 
-	var cc *astiav.CodecContext
-	var cs *astiav.Stream
+	var cc *CodecContext
+	var cs *Stream
 	for _, s := range fc.Streams() {
 		if s.CodecParameters().MediaType() != mediaType {
 			continue
@@ -143,13 +142,13 @@ func (h *helper) inputLastFrame(name string, mediaType astiav.MediaType) (f *ast
 
 		cs = s
 
-		c := astiav.FindDecoder(s.CodecParameters().CodecID())
+		c := FindDecoder(s.CodecParameters().CodecID())
 		if c == nil {
 			err = errors.New("astiav_test: no codec")
 			return
 		}
 
-		cc = astiav.AllocCodecContext(c)
+		cc = AllocCodecContext(c)
 		if cc == nil {
 			err = errors.New("astiav_test: no codec context")
 			return
@@ -173,25 +172,25 @@ func (h *helper) inputLastFrame(name string, mediaType astiav.MediaType) (f *ast
 		return
 	}
 
-	var pkt1 *astiav.Packet
+	var pkt1 *Packet
 	if pkt1, err = h.inputFirstPacket(name); err != nil {
 		err = fmt.Errorf("astiav_test: getting input first packet failed: %w", err)
 		return
 	}
 
-	pkt2 := astiav.AllocPacket()
+	pkt2 := AllocPacket()
 	h.closer.Add(pkt2.Free)
 
-	f = astiav.AllocFrame()
+	f = AllocFrame()
 	h.closer.Add(f.Free)
 
-	lastFrame := astiav.AllocFrame()
+	lastFrame := AllocFrame()
 	h.closer.Add(lastFrame.Free)
 
-	pkts := []*astiav.Packet{pkt1}
+	pkts := []*Packet{pkt1}
 	for {
 		if err = fc.ReadFrame(pkt2); err != nil {
-			if errors.Is(err, astiav.ErrEof) || errors.Is(err, astiav.ErrEagain) {
+			if errors.Is(err, ErrEof) || errors.Is(err, ErrEagain) {
 				if len(pkts) == 0 {
 					if err = f.Ref(lastFrame); err != nil {
 						err = fmt.Errorf("astiav_test: last refing frame failed: %w", err)
@@ -220,7 +219,7 @@ func (h *helper) inputLastFrame(name string, mediaType astiav.MediaType) (f *ast
 
 			for {
 				if err = cc.ReceiveFrame(f); err != nil {
-					if errors.Is(err, astiav.ErrEof) || errors.Is(err, astiav.ErrEagain) {
+					if errors.Is(err, ErrEof) || errors.Is(err, ErrEagain) {
 						err = nil
 						break
 					}
@@ -235,7 +234,7 @@ func (h *helper) inputLastFrame(name string, mediaType astiav.MediaType) (f *ast
 			}
 		}
 
-		pkts = []*astiav.Packet{}
+		pkts = []*Packet{}
 	}
 
 	h.m.Lock()
diff --git a/channel_layout.go b/channel_layout.go
index 35420a1..b5371f9 100644
--- a/channel_layout.go
+++ b/channel_layout.go
@@ -122,8 +122,7 @@ func (l ChannelLayout) copy(dst *C.struct_AVChannelLayout) error {
 }
 
 func (l ChannelLayout) clone() (ChannelLayout, error) {
-	// TODO Should it be freed?
-	cl := C.struct_AVChannelLayout{}
+	var cl C.struct_AVChannelLayout
 	err := l.copy(&cl)
 	dst := newChannelLayoutFromC(&cl)
 	return dst, err
diff --git a/channel_layout_test.go b/channel_layout_test.go
index 5121deb..1d907de 100644
--- a/channel_layout_test.go
+++ b/channel_layout_test.go
@@ -1,17 +1,16 @@
-package astiav_test
+package astiav
 
 import (
 	"testing"
 
-	"github.com/asticode/go-astiav"
 	"github.com/stretchr/testify/require"
 )
 
 func TestChannelLayout(t *testing.T) {
-	cl := astiav.ChannelLayoutStereo
+	cl := ChannelLayoutStereo
 	require.Equal(t, 2, cl.NbChannels())
 	require.Equal(t, "stereo", cl.String())
 	require.True(t, cl.Valid())
-	require.True(t, cl.Equal(astiav.ChannelLayoutStereo))
-	require.False(t, cl.Equal(astiav.ChannelLayoutMono))
+	require.True(t, cl.Equal(ChannelLayoutStereo))
+	require.False(t, cl.Equal(ChannelLayoutMono))
 }
diff --git a/class.go b/class.go
new file mode 100644
index 0000000..36623a1
--- /dev/null
+++ b/class.go
@@ -0,0 +1,134 @@
+package astiav
+
+//#cgo pkg-config: libavutil
+//#include <libavutil/log.h>
+//#include <stdint.h>
+/*
+
+static inline char* astiavClassItemName(AVClass* c, void* ptr) {
+	return (char*)c->item_name(ptr);
+}
+
+static inline AVClassCategory astiavClassCategory(AVClass* c, void* ptr) {
+	if (c->get_category) return c->get_category(ptr);
+	return c->category;
+}
+
+static inline AVClass** astiavClassParent(AVClass* c, void* ptr) {
+	if (c->parent_log_context_offset) {
+		AVClass** parent = *(AVClass ***) (((uint8_t *) ptr) + c->parent_log_context_offset);
+		if (parent && *parent) {
+			return parent;
+		}
+	}
+	return NULL;
+}
+
+*/
+import "C"
+import (
+	"fmt"
+	"sync"
+	"unsafe"
+)
+
+// https://github.com/FFmpeg/FFmpeg/blob/n5.0/libavutil/log.h#L66
+type Class struct {
+	c   *C.struct_AVClass
+	ptr unsafe.Pointer
+}
+
+func newClassFromC(ptr unsafe.Pointer) *Class {
+	if ptr == nil {
+		return nil
+	}
+	c := (**C.struct_AVClass)(ptr)
+	if c == nil {
+		return nil
+	}
+	return &Class{
+		c:   *c,
+		ptr: ptr,
+	}
+}
+
+func (c *Class) Category() ClassCategory {
+	return ClassCategory(C.astiavClassCategory(c.c, c.ptr))
+}
+
+func (c *Class) ItemName() string {
+	return C.GoString(C.astiavClassItemName(c.c, c.ptr))
+}
+
+func (c *Class) Name() string {
+	return C.GoString(c.c.class_name)
+}
+
+func (c *Class) Parent() *Class {
+	return newClassFromC(unsafe.Pointer(C.astiavClassParent(c.c, c.ptr)))
+}
+
+func (c *Class) String() string {
+	return fmt.Sprintf("%s [%s] @ %p", c.ItemName(), c.Name(), c.ptr)
+}
+
+type Classer interface {
+	Class() *Class
+}
+
+type UnknownClasser struct {
+	c *Class
+}
+
+func newUnknownClasser(ptr unsafe.Pointer) *UnknownClasser {
+	return &UnknownClasser{c: newClassFromC(ptr)}
+}
+
+func (c *UnknownClasser) Class() *Class {
+	return c.c
+}
+
+var classers = newClasserPool()
+
+type classerPool struct {
+	m sync.Mutex
+	p map[unsafe.Pointer]Classer
+}
+
+func newClasserPool() *classerPool {
+	return &classerPool{p: make(map[unsafe.Pointer]Classer)}
+}
+
+func (p *classerPool) unsafePointer(c Classer) unsafe.Pointer {
+	if c == nil {
+		return nil
+	}
+	cl := c.Class()
+	if cl == nil {
+		return nil
+	}
+	return cl.ptr
+}
+
+func (p *classerPool) set(c Classer) {
+	p.m.Lock()
+	defer p.m.Unlock()
+	if ptr := p.unsafePointer(c); ptr != nil {
+		p.p[ptr] = c
+	}
+}
+
+func (p *classerPool) del(c Classer) {
+	p.m.Lock()
+	defer p.m.Unlock()
+	if ptr := p.unsafePointer(c); ptr != nil {
+		delete(p.p, ptr)
+	}
+}
+
+func (p *classerPool) get(ptr unsafe.Pointer) (Classer, bool) {
+	p.m.Lock()
+	defer p.m.Unlock()
+	c, ok := p.p[ptr]
+	return c, ok
+}
diff --git a/class_category.go b/class_category.go
new file mode 100644
index 0000000..70ae789
--- /dev/null
+++ b/class_category.go
@@ -0,0 +1,30 @@
+package astiav
+
+//#cgo pkg-config: libavutil
+//#include <libavutil/log.h>
+import "C"
+
+// https://github.com/FFmpeg/FFmpeg/blob/n5.0/libavutil/log.h#L28
+// TODO Find a way to use C.enum_AVClassCategory instead of uint
+type ClassCategory uint
+
+const (
+	ClassCategoryBitstreamFilter   = ClassCategory(C.AV_CLASS_CATEGORY_BITSTREAM_FILTER)
+	ClassCategoryDecoder           = ClassCategory(C.AV_CLASS_CATEGORY_DECODER)
+	ClassCategoryDemuxer           = ClassCategory(C.AV_CLASS_CATEGORY_DEMUXER)
+	ClassCategoryDeviceAudioInput  = ClassCategory(C.AV_CLASS_CATEGORY_DEVICE_AUDIO_INPUT)
+	ClassCategoryDeviceAudioOutput = ClassCategory(C.AV_CLASS_CATEGORY_DEVICE_AUDIO_OUTPUT)
+	ClassCategoryDeviceInput       = ClassCategory(C.AV_CLASS_CATEGORY_DEVICE_INPUT)
+	ClassCategoryDeviceOutput      = ClassCategory(C.AV_CLASS_CATEGORY_DEVICE_OUTPUT)
+	ClassCategoryDeviceVideoInput  = ClassCategory(C.AV_CLASS_CATEGORY_DEVICE_VIDEO_INPUT)
+	ClassCategoryDeviceVideoOutput = ClassCategory(C.AV_CLASS_CATEGORY_DEVICE_VIDEO_OUTPUT)
+	ClassCategoryEncoder           = ClassCategory(C.AV_CLASS_CATEGORY_ENCODER)
+	ClassCategoryFilter            = ClassCategory(C.AV_CLASS_CATEGORY_FILTER)
+	ClassCategoryInput             = ClassCategory(C.AV_CLASS_CATEGORY_INPUT)
+	ClassCategoryMuxer             = ClassCategory(C.AV_CLASS_CATEGORY_MUXER)
+	ClassCategoryNa                = ClassCategory(C.AV_CLASS_CATEGORY_NA)
+	ClassCategoryNb                = ClassCategory(C.AV_CLASS_CATEGORY_NB)
+	ClassCategoryOutput            = ClassCategory(C.AV_CLASS_CATEGORY_OUTPUT)
+	ClassCategorySwresampler       = ClassCategory(C.AV_CLASS_CATEGORY_SWRESAMPLER)
+	ClassCategorySwscaler          = ClassCategory(C.AV_CLASS_CATEGORY_SWSCALER)
+)
diff --git a/class_test.go b/class_test.go
new file mode 100644
index 0000000..33ebc41
--- /dev/null
+++ b/class_test.go
@@ -0,0 +1,63 @@
+package astiav
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"testing"
+	"unsafe"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestClass(t *testing.T) {
+	c := FindDecoder(CodecIDMjpeg)
+	require.NotNil(t, c)
+	cc := AllocCodecContext(c)
+	require.NotNil(t, cc)
+	defer cc.Free()
+
+	cl := cc.Class()
+	require.NotNil(t, cl)
+	require.Equal(t, ClassCategoryDecoder, cl.Category())
+	require.Equal(t, "mjpeg", cl.ItemName())
+	require.Equal(t, "AVCodecContext", cl.Name())
+	require.Equal(t, fmt.Sprintf("mjpeg [AVCodecContext] @ %p", cc.c), cl.String())
+	// TODO Test parent
+}
+
+func TestClassers(t *testing.T) {
+	cl := len(classers.p)
+	f := AllocFilterGraph()
+	c := FindDecoder(CodecIDMjpeg)
+	require.NotNil(t, c)
+	cc := AllocCodecContext(c)
+	require.NotNil(t, cc)
+	bufferSink := FindFilterByName("buffersink")
+	require.NotNil(t, bufferSink)
+	fc, err := f.NewFilterContext(bufferSink, "filter_out", nil)
+	require.NoError(t, err)
+	fmc1 := AllocFormatContext()
+	fmc2 := AllocFormatContext()
+	require.NoError(t, fmc2.OpenInput("testdata/video.mp4", nil, nil))
+	path := filepath.Join(t.TempDir(), "iocontext.txt")
+	ic, err := OpenIOContext(path, NewIOContextFlags(IOContextFlagWrite))
+	require.NoError(t, err)
+	defer os.RemoveAll(path)
+	ssc, err := CreateSoftwareScaleContext(1, 1, PixelFormatRgba, 2, 2, PixelFormatRgba, NewSoftwareScaleContextFlags())
+	require.NoError(t, err)
+
+	require.Equal(t, cl+8, len(classers.p))
+	v, ok := classers.get(unsafe.Pointer(f.c))
+	require.True(t, ok)
+	require.Equal(t, f, v)
+
+	cc.Free()
+	fc.Free()
+	f.Free()
+	fmc1.Free()
+	fmc2.CloseInput()
+	require.NoError(t, ic.Closep())
+	ssc.Free()
+	require.Equal(t, cl, len(classers.p))
+}
diff --git a/codec_context.go b/codec_context.go
index 4bdb85e..556e82e 100644
--- a/codec_context.go
+++ b/codec_context.go
@@ -39,6 +39,17 @@ type CodecContext struct {
 	hdc *HardwareDeviceContext
 }
 
+func newCodecContextFromC(c *C.struct_AVCodecContext) *CodecContext {
+	if c == nil {
+		return nil
+	}
+	cc := &CodecContext{c: c}
+	classers.set(cc)
+	return cc
+}
+
+var _ Classer = (*CodecContext)(nil)
+
 func AllocCodecContext(c *Codec) *CodecContext {
 	var cc *C.struct_AVCodec
 	if c != nil {
@@ -47,18 +58,12 @@ func AllocCodecContext(c *Codec) *CodecContext {
 	return newCodecContextFromC(C.avcodec_alloc_context3(cc))
 }
 
-func newCodecContextFromC(c *C.struct_AVCodecContext) *CodecContext {
-	if c == nil {
-		return nil
-	}
-	return &CodecContext{c: c}
-}
-
 func (cc *CodecContext) Free() {
 	if cc.hdc != nil {
 		C.av_buffer_unref(&cc.hdc.c)
 		cc.hdc = nil
 	}
+	classers.del(cc)
 	C.avcodec_free_context(&cc.c)
 }
 
@@ -99,6 +104,10 @@ func (cc *CodecContext) ChromaLocation() ChromaLocation {
 	return ChromaLocation(cc.c.chroma_sample_location)
 }
 
+func (cc *CodecContext) Class() *Class {
+	return newClassFromC(unsafe.Pointer(cc.c))
+}
+
 func (cc *CodecContext) CodecID() CodecID {
 	return CodecID(cc.c.codec_id)
 }
diff --git a/codec_context_test.go b/codec_context_test.go
index 11fc336..b9badb0 100644
--- a/codec_context_test.go
+++ b/codec_context_test.go
@@ -1,9 +1,8 @@
-package astiav_test
+package astiav
 
 import (
 	"testing"
 
-	"github.com/asticode/go-astiav"
 	"github.com/stretchr/testify/require"
 )
 
@@ -15,36 +14,39 @@ func TestCodecContext(t *testing.T) {
 	s1 := ss[0]
 	s2 := ss[1]
 
-	c1 := astiav.FindDecoder(s1.CodecParameters().CodecID())
+	c1 := FindDecoder(s1.CodecParameters().CodecID())
 	require.NotNil(t, c1)
-	cc1 := astiav.AllocCodecContext(c1)
+	cc1 := AllocCodecContext(c1)
 	require.NotNil(t, cc1)
 	defer cc1.Free()
 	err = s1.CodecParameters().ToCodecContext(cc1)
 	require.NoError(t, err)
 	require.Equal(t, "Video: h264 (Constrained Baseline) (avc1 / 0x31637661), yuv420p(progressive), 320x180 [SAR 1:1 DAR 16:9], 441 kb/s", cc1.String())
 	require.Equal(t, int64(441324), cc1.BitRate())
-	require.Equal(t, astiav.ChromaLocationLeft, cc1.ChromaLocation())
-	require.Equal(t, astiav.CodecIDH264, cc1.CodecID())
-	require.Equal(t, astiav.ColorPrimariesUnspecified, cc1.ColorPrimaries())
-	require.Equal(t, astiav.ColorRangeUnspecified, cc1.ColorRange())
-	require.Equal(t, astiav.ColorSpaceUnspecified, cc1.ColorSpace())
-	require.Equal(t, astiav.ColorTransferCharacteristicUnspecified, cc1.ColorTransferCharacteristic())
+	require.Equal(t, ChromaLocationLeft, cc1.ChromaLocation())
+	require.Equal(t, CodecIDH264, cc1.CodecID())
+	require.Equal(t, ColorPrimariesUnspecified, cc1.ColorPrimaries())
+	require.Equal(t, ColorRangeUnspecified, cc1.ColorRange())
+	require.Equal(t, ColorSpaceUnspecified, cc1.ColorSpace())
+	require.Equal(t, ColorTransferCharacteristicUnspecified, cc1.ColorTransferCharacteristic())
 	require.Equal(t, 12, cc1.GopSize())
 	require.Equal(t, 180, cc1.Height())
-	require.Equal(t, astiav.Level(13), cc1.Level())
-	require.Equal(t, astiav.MediaTypeVideo, cc1.MediaType())
-	require.Equal(t, astiav.PixelFormatYuv420P, cc1.PixelFormat())
-	require.Equal(t, astiav.ProfileH264ConstrainedBaseline, cc1.Profile())
-	require.Equal(t, astiav.NewRational(1, 1), cc1.SampleAspectRatio())
-	require.Equal(t, astiav.StrictStdComplianceNormal, cc1.StrictStdCompliance())
+	require.Equal(t, Level(13), cc1.Level())
+	require.Equal(t, MediaTypeVideo, cc1.MediaType())
+	require.Equal(t, PixelFormatYuv420P, cc1.PixelFormat())
+	require.Equal(t, ProfileH264ConstrainedBaseline, cc1.Profile())
+	require.Equal(t, NewRational(1, 1), cc1.SampleAspectRatio())
+	require.Equal(t, StrictStdComplianceNormal, cc1.StrictStdCompliance())
 	require.Equal(t, 1, cc1.ThreadCount())
-	require.Equal(t, astiav.ThreadType(3), cc1.ThreadType())
+	require.Equal(t, ThreadType(3), cc1.ThreadType())
 	require.Equal(t, 320, cc1.Width())
+	cl := cc1.Class()
+	require.NotNil(t, cl)
+	require.Equal(t, "AVCodecContext", cl.Name())
 
-	c2 := astiav.FindDecoder(s2.CodecParameters().CodecID())
+	c2 := FindDecoder(s2.CodecParameters().CodecID())
 	require.NotNil(t, c2)
-	cc2 := astiav.AllocCodecContext(c2)
+	cc2 := AllocCodecContext(c2)
 	require.NotNil(t, cc2)
 	defer cc2.Free()
 	err = s2.CodecParameters().ToCodecContext(cc2)
@@ -52,66 +54,66 @@ func TestCodecContext(t *testing.T) {
 	require.Equal(t, "Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 161 kb/s", cc2.String())
 	require.Equal(t, int64(161052), cc2.BitRate())
 	require.Equal(t, 2, cc2.Channels())
-	require.True(t, cc2.ChannelLayout().Equal(astiav.ChannelLayoutStereo))
-	require.Equal(t, astiav.CodecIDAac, cc2.CodecID())
+	require.True(t, cc2.ChannelLayout().Equal(ChannelLayoutStereo))
+	require.Equal(t, CodecIDAac, cc2.CodecID())
 	require.Equal(t, 1024, cc2.FrameSize())
-	require.Equal(t, astiav.MediaTypeAudio, cc2.MediaType())
-	require.Equal(t, astiav.SampleFormatFltp, cc2.SampleFormat())
+	require.Equal(t, MediaTypeAudio, cc2.MediaType())
+	require.Equal(t, SampleFormatFltp, cc2.SampleFormat())
 	require.Equal(t, 48000, cc2.SampleRate())
-	require.Equal(t, astiav.StrictStdComplianceNormal, cc2.StrictStdCompliance())
+	require.Equal(t, StrictStdComplianceNormal, cc2.StrictStdCompliance())
 	require.Equal(t, 1, cc2.ThreadCount())
-	require.Equal(t, astiav.ThreadType(3), cc2.ThreadType())
+	require.Equal(t, ThreadType(3), cc2.ThreadType())
 
-	c3 := astiav.FindEncoder(astiav.CodecIDMjpeg)
+	c3 := FindEncoder(CodecIDMjpeg)
 	require.NotNil(t, c3)
-	cc3 := astiav.AllocCodecContext(c3)
+	cc3 := AllocCodecContext(c3)
 	require.NotNil(t, cc3)
 	defer cc3.Free()
 	cc3.SetHeight(2)
-	cc3.SetPixelFormat(astiav.PixelFormatYuvj420P)
-	cc3.SetTimeBase(astiav.NewRational(1, 1))
+	cc3.SetPixelFormat(PixelFormatYuvj420P)
+	cc3.SetTimeBase(NewRational(1, 1))
 	cc3.SetWidth(3)
 	err = cc3.Open(c3, nil)
 	require.NoError(t, err)
 
-	cc4 := astiav.AllocCodecContext(nil)
+	cc4 := AllocCodecContext(nil)
 	require.NotNil(t, cc4)
 	defer cc4.Free()
 	cc4.SetBitRate(1)
-	cc4.SetChannelLayout(astiav.ChannelLayout21)
+	cc4.SetChannelLayout(ChannelLayout21)
 	cc4.SetChannels(3)
-	cc4.SetFlags(astiav.NewCodecContextFlags(4))
-	cc4.SetFlags2(astiav.NewCodecContextFlags2(5))
-	cc4.SetFramerate(astiav.NewRational(6, 1))
+	cc4.SetFlags(NewCodecContextFlags(4))
+	cc4.SetFlags2(NewCodecContextFlags2(5))
+	cc4.SetFramerate(NewRational(6, 1))
 	cc4.SetGopSize(7)
 	cc4.SetHeight(8)
-	cc4.SetPixelFormat(astiav.PixelFormat0Bgr)
+	cc4.SetPixelFormat(PixelFormat0Bgr)
 	cc4.SetQmin(5)
-	cc4.SetSampleAspectRatio(astiav.NewRational(10, 1))
-	cc4.SetSampleFormat(astiav.SampleFormatDbl)
+	cc4.SetSampleAspectRatio(NewRational(10, 1))
+	cc4.SetSampleFormat(SampleFormatDbl)
 	cc4.SetSampleRate(12)
-	cc4.SetStrictStdCompliance(astiav.StrictStdComplianceExperimental)
+	cc4.SetStrictStdCompliance(StrictStdComplianceExperimental)
 	cc4.SetThreadCount(13)
-	cc4.SetThreadType(astiav.ThreadTypeSlice)
-	cc4.SetTimeBase(astiav.NewRational(15, 1))
+	cc4.SetThreadType(ThreadTypeSlice)
+	cc4.SetTimeBase(NewRational(15, 1))
 	cc4.SetWidth(16)
 	require.Equal(t, int64(1), cc4.BitRate())
-	require.True(t, cc4.ChannelLayout().Equal(astiav.ChannelLayout21))
+	require.True(t, cc4.ChannelLayout().Equal(ChannelLayout21))
 	require.Equal(t, 3, cc4.Channels())
-	require.Equal(t, astiav.NewCodecContextFlags(4), cc4.Flags())
-	require.Equal(t, astiav.NewCodecContextFlags2(5), cc4.Flags2())
-	require.Equal(t, astiav.NewRational(6, 1), cc4.Framerate())
+	require.Equal(t, NewCodecContextFlags(4), cc4.Flags())
+	require.Equal(t, NewCodecContextFlags2(5), cc4.Flags2())
+	require.Equal(t, NewRational(6, 1), cc4.Framerate())
 	require.Equal(t, 7, cc4.GopSize())
 	require.Equal(t, 8, cc4.Height())
-	require.Equal(t, astiav.PixelFormat0Bgr, cc4.PixelFormat())
+	require.Equal(t, PixelFormat0Bgr, cc4.PixelFormat())
 	require.Equal(t, 5, cc4.Qmin())
-	require.Equal(t, astiav.NewRational(10, 1), cc4.SampleAspectRatio())
-	require.Equal(t, astiav.SampleFormatDbl, cc4.SampleFormat())
+	require.Equal(t, NewRational(10, 1), cc4.SampleAspectRatio())
+	require.Equal(t, SampleFormatDbl, cc4.SampleFormat())
 	require.Equal(t, 12, cc4.SampleRate())
-	require.Equal(t, astiav.StrictStdComplianceExperimental, cc4.StrictStdCompliance())
+	require.Equal(t, StrictStdComplianceExperimental, cc4.StrictStdCompliance())
 	require.Equal(t, 13, cc4.ThreadCount())
-	require.Equal(t, astiav.ThreadTypeSlice, cc4.ThreadType())
-	require.Equal(t, astiav.NewRational(15, 1), cc4.TimeBase())
+	require.Equal(t, ThreadTypeSlice, cc4.ThreadType())
+	require.Equal(t, NewRational(15, 1), cc4.TimeBase())
 	require.Equal(t, 16, cc4.Width())
 
 	// TODO Test ReceivePacket
diff --git a/codec_id_test.go b/codec_id_test.go
index fb46dc0..9a5c941 100644
--- a/codec_id_test.go
+++ b/codec_id_test.go
@@ -1,14 +1,13 @@
-package astiav_test
+package astiav
 
 import (
 	"testing"
 
-	"github.com/asticode/go-astiav"
 	"github.com/stretchr/testify/require"
 )
 
 func TestCodecID(t *testing.T) {
-	require.Equal(t, astiav.MediaTypeVideo, astiav.CodecIDH264.MediaType())
-	require.Equal(t, "h264", astiav.CodecIDH264.Name())
-	require.Equal(t, "h264", astiav.CodecIDH264.String())
+	require.Equal(t, MediaTypeVideo, CodecIDH264.MediaType())
+	require.Equal(t, "h264", CodecIDH264.Name())
+	require.Equal(t, "h264", CodecIDH264.String())
 }
diff --git a/codec_parameters_test.go b/codec_parameters_test.go
index 2d632be..9d40eb8 100644
--- a/codec_parameters_test.go
+++ b/codec_parameters_test.go
@@ -1,9 +1,8 @@
-package astiav_test
+package astiav
 
 import (
 	"testing"
 
-	"github.com/asticode/go-astiav"
 	"github.com/stretchr/testify/require"
 )
 
@@ -17,75 +16,75 @@ func TestCodecParameters(t *testing.T) {
 
 	cp1 := s1.CodecParameters()
 	require.Equal(t, int64(441324), cp1.BitRate())
-	require.Equal(t, astiav.ChromaLocationLeft, cp1.ChromaLocation())
-	require.Equal(t, astiav.CodecIDH264, cp1.CodecID())
-	require.Equal(t, astiav.CodecTag(0x31637661), cp1.CodecTag())
-	require.Equal(t, astiav.ColorPrimariesUnspecified, cp1.ColorPrimaries())
-	require.Equal(t, astiav.ColorRangeUnspecified, cp1.ColorRange())
-	require.Equal(t, astiav.ColorSpaceUnspecified, cp1.ColorSpace())
-	require.Equal(t, astiav.ColorTransferCharacteristicUnspecified, cp1.ColorTransferCharacteristic())
+	require.Equal(t, ChromaLocationLeft, cp1.ChromaLocation())
+	require.Equal(t, CodecIDH264, cp1.CodecID())
+	require.Equal(t, CodecTag(0x31637661), cp1.CodecTag())
+	require.Equal(t, ColorPrimariesUnspecified, cp1.ColorPrimaries())
+	require.Equal(t, ColorRangeUnspecified, cp1.ColorRange())
+	require.Equal(t, ColorSpaceUnspecified, cp1.ColorSpace())
+	require.Equal(t, ColorTransferCharacteristicUnspecified, cp1.ColorTransferCharacteristic())
 	require.Equal(t, 180, cp1.Height())
-	require.Equal(t, astiav.Level(13), cp1.Level())
-	require.Equal(t, astiav.MediaTypeVideo, cp1.MediaType())
-	require.Equal(t, astiav.PixelFormatYuv420P, cp1.PixelFormat())
-	require.Equal(t, astiav.ProfileH264ConstrainedBaseline, cp1.Profile())
-	require.Equal(t, astiav.NewRational(1, 1), cp1.SampleAspectRatio())
+	require.Equal(t, Level(13), cp1.Level())
+	require.Equal(t, MediaTypeVideo, cp1.MediaType())
+	require.Equal(t, PixelFormatYuv420P, cp1.PixelFormat())
+	require.Equal(t, ProfileH264ConstrainedBaseline, cp1.Profile())
+	require.Equal(t, NewRational(1, 1), cp1.SampleAspectRatio())
 	require.Equal(t, 320, cp1.Width())
 
 	cp2 := s2.CodecParameters()
 	require.Equal(t, int64(161052), cp2.BitRate())
 	require.Equal(t, 2, cp2.Channels())
-	require.True(t, cp2.ChannelLayout().Equal(astiav.ChannelLayoutStereo))
-	require.Equal(t, astiav.CodecIDAac, cp2.CodecID())
-	require.Equal(t, astiav.CodecTag(0x6134706d), cp2.CodecTag())
+	require.True(t, cp2.ChannelLayout().Equal(ChannelLayoutStereo))
+	require.Equal(t, CodecIDAac, cp2.CodecID())
+	require.Equal(t, CodecTag(0x6134706d), cp2.CodecTag())
 	require.Equal(t, 1024, cp2.FrameSize())
-	require.Equal(t, astiav.MediaTypeAudio, cp2.MediaType())
-	require.Equal(t, astiav.SampleFormatFltp, cp2.SampleFormat())
+	require.Equal(t, MediaTypeAudio, cp2.MediaType())
+	require.Equal(t, SampleFormatFltp, cp2.SampleFormat())
 	require.Equal(t, 48000, cp2.SampleRate())
 
-	cp3 := astiav.AllocCodecParameters()
+	cp3 := AllocCodecParameters()
 	require.NotNil(t, cp3)
 	defer cp3.Free()
 	err = cp2.Copy(cp3)
 	require.NoError(t, err)
 	require.Equal(t, 2, cp3.Channels())
 
-	cc4 := astiav.AllocCodecContext(nil)
+	cc4 := AllocCodecContext(nil)
 	require.NotNil(t, cc4)
 	defer cc4.Free()
 	err = cp2.ToCodecContext(cc4)
 	require.NoError(t, err)
 	require.Equal(t, 2, cc4.Channels())
 
-	cp5 := astiav.AllocCodecParameters()
+	cp5 := AllocCodecParameters()
 	require.NotNil(t, cp5)
 	defer cp5.Free()
 	err = cp5.FromCodecContext(cc4)
 	require.NoError(t, err)
 	require.Equal(t, 2, cp5.Channels())
 
-	cp6 := astiav.AllocCodecParameters()
+	cp6 := AllocCodecParameters()
 	require.NotNil(t, cp6)
 	defer cp6.Free()
-	cp6.SetChannelLayout(astiav.ChannelLayout21)
-	require.True(t, cp6.ChannelLayout().Equal(astiav.ChannelLayout21))
+	cp6.SetChannelLayout(ChannelLayout21)
+	require.True(t, cp6.ChannelLayout().Equal(ChannelLayout21))
 	defer cp6.Free()
 	cp6.SetChannels(3)
 	require.Equal(t, 3, cp6.Channels())
-	cp6.SetCodecID(astiav.CodecIDRawvideo)
-	require.Equal(t, astiav.CodecIDRawvideo, cp6.CodecID())
-	cp6.SetCodecTag(astiav.CodecTag(2))
-	require.Equal(t, astiav.CodecTag(2), cp6.CodecTag())
-	cp6.SetCodecType(astiav.MediaTypeAudio)
-	require.Equal(t, astiav.MediaTypeAudio, cp6.CodecType())
+	cp6.SetCodecID(CodecIDRawvideo)
+	require.Equal(t, CodecIDRawvideo, cp6.CodecID())
+	cp6.SetCodecTag(CodecTag(2))
+	require.Equal(t, CodecTag(2), cp6.CodecTag())
+	cp6.SetCodecType(MediaTypeAudio)
+	require.Equal(t, MediaTypeAudio, cp6.CodecType())
 	cp6.SetHeight(1)
 	require.Equal(t, 1, cp6.Height())
-	cp6.SetPixelFormat(astiav.PixelFormat0Bgr)
-	require.Equal(t, astiav.PixelFormat0Bgr, cp6.PixelFormat())
-	cp6.SetSampleAspectRatio(astiav.NewRational(1, 2))
-	require.Equal(t, astiav.NewRational(1, 2), cp6.SampleAspectRatio())
-	cp6.SetSampleFormat(astiav.SampleFormatDbl)
-	require.Equal(t, astiav.SampleFormatDbl, cp6.SampleFormat())
+	cp6.SetPixelFormat(PixelFormat0Bgr)
+	require.Equal(t, PixelFormat0Bgr, cp6.PixelFormat())
+	cp6.SetSampleAspectRatio(NewRational(1, 2))
+	require.Equal(t, NewRational(1, 2), cp6.SampleAspectRatio())
+	cp6.SetSampleFormat(SampleFormatDbl)
+	require.Equal(t, SampleFormatDbl, cp6.SampleFormat())
 	cp6.SetSampleRate(4)
 	require.Equal(t, 4, cp6.SampleRate())
 	cp6.SetWidth(2)
diff --git a/codec_test.go b/codec_test.go
index 8dc5ae5..8562123 100644
--- a/codec_test.go
+++ b/codec_test.go
@@ -1,34 +1,33 @@
-package astiav_test
+package astiav
 
 import (
 	"testing"
 
-	"github.com/asticode/go-astiav"
 	"github.com/stretchr/testify/require"
 )
 
 func TestCodec(t *testing.T) {
-	c := astiav.FindDecoder(astiav.CodecIDMp3)
+	c := FindDecoder(CodecIDMp3)
 	require.NotNil(t, c)
-	require.Equal(t, c.ID(), astiav.CodecIDMp3)
+	require.Equal(t, c.ID(), CodecIDMp3)
 	require.Nil(t, c.ChannelLayouts())
 	require.True(t, c.IsDecoder())
 	require.False(t, c.IsEncoder())
 	require.Nil(t, c.PixelFormats())
-	require.Equal(t, []astiav.SampleFormat{astiav.SampleFormatFltp, astiav.SampleFormatFlt}, c.SampleFormats())
+	require.Equal(t, []SampleFormat{SampleFormatFltp, SampleFormatFlt}, c.SampleFormats())
 	require.Equal(t, "mp3float", c.Name())
 	require.Equal(t, "mp3float", c.String())
 
-	c = astiav.FindDecoderByName("aac")
+	c = FindDecoderByName("aac")
 	require.NotNil(t, c)
-	els := []astiav.ChannelLayout{
-		astiav.ChannelLayoutMono,
-		astiav.ChannelLayoutStereo,
-		astiav.ChannelLayoutSurround,
-		astiav.ChannelLayout4Point0,
-		astiav.ChannelLayout5Point0Back,
-		astiav.ChannelLayout5Point1Back,
-		astiav.ChannelLayout7Point1WideBack,
+	els := []ChannelLayout{
+		ChannelLayoutMono,
+		ChannelLayoutStereo,
+		ChannelLayoutSurround,
+		ChannelLayout4Point0,
+		ChannelLayout5Point0Back,
+		ChannelLayout5Point1Back,
+		ChannelLayout7Point1WideBack,
 	}
 	gls := c.ChannelLayouts()
 	require.Len(t, gls, len(els))
@@ -37,40 +36,40 @@ func TestCodec(t *testing.T) {
 	}
 	require.True(t, c.IsDecoder())
 	require.False(t, c.IsEncoder())
-	require.Equal(t, []astiav.SampleFormat{astiav.SampleFormatFltp}, c.SampleFormats())
+	require.Equal(t, []SampleFormat{SampleFormatFltp}, c.SampleFormats())
 	require.Equal(t, "aac", c.Name())
 	require.Equal(t, "aac", c.String())
 
-	c = astiav.FindEncoder(astiav.CodecIDMjpeg)
+	c = FindEncoder(CodecIDMjpeg)
 	require.NotNil(t, c)
 	require.False(t, c.IsDecoder())
 	require.True(t, c.IsEncoder())
-	require.Contains(t, c.PixelFormats(), astiav.PixelFormatYuvj420P)
+	require.Contains(t, c.PixelFormats(), PixelFormatYuvj420P)
 	require.Nil(t, c.SampleFormats())
 	require.Contains(t, c.Name(), "mjpeg")
 	require.Contains(t, c.String(), "mjpeg")
 
-	c = astiav.FindEncoderByName("mjpeg")
+	c = FindEncoderByName("mjpeg")
 	require.NotNil(t, c)
 	require.False(t, c.IsDecoder())
 	require.True(t, c.IsEncoder())
-	require.Equal(t, []astiav.PixelFormat{
-		astiav.PixelFormatYuvj420P,
-		astiav.PixelFormatYuvj422P,
-		astiav.PixelFormatYuvj444P,
-		astiav.PixelFormatYuv420P,
-		astiav.PixelFormatYuv422P,
-		astiav.PixelFormatYuv444P,
+	require.Equal(t, []PixelFormat{
+		PixelFormatYuvj420P,
+		PixelFormatYuvj422P,
+		PixelFormatYuvj444P,
+		PixelFormatYuv420P,
+		PixelFormatYuv422P,
+		PixelFormatYuv444P,
 	}, c.PixelFormats())
 	require.Equal(t, "mjpeg", c.Name())
 	require.Equal(t, "mjpeg", c.String())
 
-	c = astiav.FindDecoderByName("invalid")
+	c = FindDecoderByName("invalid")
 	require.Nil(t, c)
 
 	var found bool
-	for _, c := range astiav.Codecs() {
-		if c.ID() == astiav.CodecIDMjpeg {
+	for _, c := range Codecs() {
+		if c.ID() == CodecIDMjpeg {
 			found = true
 		}
 	}
diff --git a/device_test.go b/device_test.go
index 9eff1b9..010fb1f 100644
--- a/device_test.go
+++ b/device_test.go
@@ -1,11 +1,9 @@
-package astiav_test
+package astiav
 
 import (
 	"testing"
-
-	"github.com/asticode/go-astiav"
 )
 
 func TestDevice(t *testing.T) {
-	astiav.RegisterAllDevices()
+	RegisterAllDevices()
 }
diff --git a/error_test.go b/error_test.go
index 7f2adaa..97844f7 100644
--- a/error_test.go
+++ b/error_test.go
@@ -1,11 +1,10 @@
-package astiav_test
+package astiav
 
 import (
 	"errors"
 	"fmt"
 	"testing"
 
-	"github.com/asticode/go-astiav"
 	"github.com/stretchr/testify/require"
 )
 
@@ -14,10 +13,10 @@ type testError struct{}
 func (err testError) Error() string { return "" }
 
 func TestError(t *testing.T) {
-	require.Equal(t, "Decoder not found", astiav.ErrDecoderNotFound.Error())
-	err1 := fmt.Errorf("test 1: %w", astiav.ErrDecoderNotFound)
-	require.True(t, errors.Is(err1, astiav.ErrDecoderNotFound))
+	require.Equal(t, "Decoder not found", ErrDecoderNotFound.Error())
+	err1 := fmt.Errorf("test 1: %w", ErrDecoderNotFound)
+	require.True(t, errors.Is(err1, ErrDecoderNotFound))
 	require.False(t, errors.Is(err1, testError{}))
-	err2 := fmt.Errorf("test 2: %w", astiav.ErrDemuxerNotFound)
-	require.False(t, errors.Is(err2, astiav.ErrDecoderNotFound))
+	err2 := fmt.Errorf("test 2: %w", ErrDemuxerNotFound)
+	require.False(t, errors.Is(err2, ErrDecoderNotFound))
 }
diff --git a/examples/demuxing_decoding/main.go b/examples/demuxing_decoding/main.go
index fdc8f0c..4b43bbe 100644
--- a/examples/demuxing_decoding/main.go
+++ b/examples/demuxing_decoding/main.go
@@ -23,8 +23,14 @@ type stream struct {
 func main() {
 	// Handle ffmpeg logs
 	astiav.SetLogLevel(astiav.LogLevelDebug)
-	astiav.SetLogCallback(func(l astiav.LogLevel, fmt, msg, parent string) {
-		log.Printf("ffmpeg log: %s (level: %d)\n", strings.TrimSpace(msg), l)
+	astiav.SetLogCallback(func(c astiav.Classer, l astiav.LogLevel, fmt, msg string) {
+		var cs string
+		if c != nil {
+			if cl := c.Class(); cl != nil {
+				cs = " - class: " + cl.String()
+			}
+		}
+		log.Printf("ffmpeg log: %s%s - level: %d\n", strings.TrimSpace(msg), cs, l)
 	})
 
 	// Parse flags
diff --git a/examples/filtering/main.go b/examples/filtering/main.go
index 0028114..9090fc0 100644
--- a/examples/filtering/main.go
+++ b/examples/filtering/main.go
@@ -37,8 +37,14 @@ type stream struct {
 func main() {
 	// Handle ffmpeg logs
 	astiav.SetLogLevel(astiav.LogLevelDebug)
-	astiav.SetLogCallback(func(l astiav.LogLevel, fmt, msg, parent string) {
-		log.Printf("ffmpeg log: %s (level: %d)\n", strings.TrimSpace(msg), l)
+	astiav.SetLogCallback(func(c astiav.Classer, l astiav.LogLevel, fmt, msg string) {
+		var cs string
+		if c != nil {
+			if cl := c.Class(); cl != nil {
+				cs = " - class: " + cl.String()
+			}
+		}
+		log.Printf("ffmpeg log: %s%s - level: %d\n", strings.TrimSpace(msg), cs, l)
 	})
 
 	// Parse flags
diff --git a/examples/hardware_decoding/main.go b/examples/hardware_decoding/main.go
index 0056570..5d15f93 100644
--- a/examples/hardware_decoding/main.go
+++ b/examples/hardware_decoding/main.go
@@ -28,8 +28,14 @@ type stream struct {
 func main() {
 	// Handle ffmpeg logs
 	astiav.SetLogLevel(astiav.LogLevelDebug)
-	astiav.SetLogCallback(func(l astiav.LogLevel, fmt, msg, parent string) {
-		log.Printf("ffmpeg log: %s (level: %d)\n", strings.TrimSpace(msg), l)
+	astiav.SetLogCallback(func(c astiav.Classer, l astiav.LogLevel, fmt, msg string) {
+		var cs string
+		if c != nil {
+			if cl := c.Class(); cl != nil {
+				cs = " - class: " + cl.String()
+			}
+		}
+		log.Printf("ffmpeg log: %s%s - level: %d\n", strings.TrimSpace(msg), cs, l)
 	})
 
 	// Parse flags
diff --git a/examples/remuxing/main.go b/examples/remuxing/main.go
index 65c7c47..8ef74e5 100644
--- a/examples/remuxing/main.go
+++ b/examples/remuxing/main.go
@@ -18,8 +18,14 @@ var (
 func main() {
 	// Handle ffmpeg logs
 	astiav.SetLogLevel(astiav.LogLevelDebug)
-	astiav.SetLogCallback(func(l astiav.LogLevel, fmt, msg, parent string) {
-		log.Printf("ffmpeg log: %s (level: %d)\n", strings.TrimSpace(msg), l)
+	astiav.SetLogCallback(func(c astiav.Classer, l astiav.LogLevel, fmt, msg string) {
+		var cs string
+		if c != nil {
+			if cl := c.Class(); cl != nil {
+				cs = " - class: " + cl.String()
+			}
+		}
+		log.Printf("ffmpeg log: %s%s - level: %d\n", strings.TrimSpace(msg), cs, l)
 	})
 
 	// Parse flags
@@ -96,11 +102,9 @@ func main() {
 
 	// If this is a file, we need to use an io context
 	if !outputFormatContext.OutputFormat().Flags().Has(astiav.IOFormatFlagNofile) {
-		// Create io context
-		ioContext := astiav.NewIOContext()
-
 		// Open io context
-		if err = ioContext.Open(*output, astiav.NewIOContextFlags(astiav.IOContextFlagWrite)); err != nil {
+		ioContext, err := astiav.OpenIOContext(*output, astiav.NewIOContextFlags(astiav.IOContextFlagWrite))
+		if err != nil {
 			log.Fatal(fmt.Errorf("main: opening io context failed: %w", err))
 		}
 		defer ioContext.Closep() //nolint:errcheck
diff --git a/examples/scaling/main.go b/examples/scaling/main.go
index e8921ba..640c8a1 100644
--- a/examples/scaling/main.go
+++ b/examples/scaling/main.go
@@ -20,8 +20,14 @@ var (
 func main() {
 	// Handle ffmpeg logs
 	astiav.SetLogLevel(astiav.LogLevelDebug)
-	astiav.SetLogCallback(func(l astiav.LogLevel, fmt, msg, parent string) {
-		log.Printf("ffmpeg log: %s (level: %d)\n", strings.TrimSpace(msg), l)
+	astiav.SetLogCallback(func(c astiav.Classer, l astiav.LogLevel, fmt, msg string) {
+		var cs string
+		if c != nil {
+			if cl := c.Class(); cl != nil {
+				cs = " - class: " + cl.String()
+			}
+		}
+		log.Printf("ffmpeg log: %s%s - level: %d\n", strings.TrimSpace(msg), cs, l)
 	})
 
 	// Parse flags
diff --git a/examples/transcoding/main.go b/examples/transcoding/main.go
index 5c629b8..6726856 100644
--- a/examples/transcoding/main.go
+++ b/examples/transcoding/main.go
@@ -42,8 +42,14 @@ type stream struct {
 func main() {
 	// Handle ffmpeg logs
 	astiav.SetLogLevel(astiav.LogLevelDebug)
-	astiav.SetLogCallback(func(l astiav.LogLevel, fmt, msg, parent string) {
-		log.Printf("ffmpeg log: %s (level: %d)\n", strings.TrimSpace(msg), l)
+	astiav.SetLogCallback(func(c astiav.Classer, l astiav.LogLevel, fmt, msg string) {
+		var cs string
+		if c != nil {
+			if cl := c.Class(); cl != nil {
+				cs = " - class: " + cl.String()
+			}
+		}
+		log.Printf("ffmpeg log: %s%s - level: %d\n", strings.TrimSpace(msg), cs, l)
 	})
 
 	// Parse flags
@@ -306,11 +312,9 @@ func openOutputFile() (err error) {
 
 	// If this is a file, we need to use an io context
 	if !outputFormatContext.OutputFormat().Flags().Has(astiav.IOFormatFlagNofile) {
-		// Create io context
-		ioContext := astiav.NewIOContext()
-
 		// Open io context
-		if err = ioContext.Open(*output, astiav.NewIOContextFlags(astiav.IOContextFlagWrite)); err != nil {
+		var ioContext *astiav.IOContext
+		if ioContext, err = astiav.OpenIOContext(*output, astiav.NewIOContextFlags(astiav.IOContextFlagWrite)); err != nil {
 			err = fmt.Errorf("main: opening io context failed: %w", err)
 			return
 		}
diff --git a/filter_context.go b/filter_context.go
index 90a2d31..94325ee 100644
--- a/filter_context.go
+++ b/filter_context.go
@@ -6,18 +6,28 @@ package astiav
 //#include <libavfilter/buffersrc.h>
 //#include <libavutil/frame.h>
 import "C"
-import "unsafe"
+import (
+	"unsafe"
+)
 
 // https://github.com/FFmpeg/FFmpeg/blob/n5.0/libavfilter/avfilter.h#L67
 type FilterContext struct {
 	c *C.struct_AVFilterContext
 }
 
-func newFilterContext() *FilterContext {
-	return &FilterContext{}
+func newFilterContext(c *C.struct_AVFilterContext) *FilterContext {
+	if c == nil {
+		return nil
+	}
+	fc := &FilterContext{c: c}
+	classers.set(fc)
+	return fc
 }
 
+var _ Classer = (*FilterContext)(nil)
+
 func (fc *FilterContext) Free() {
+	classers.del(fc)
 	C.avfilter_free(fc.c)
 }
 
@@ -37,6 +47,10 @@ func (fc *FilterContext) BuffersinkGetFrame(f *Frame, fs BuffersinkFlags) error
 	return newError(C.av_buffersink_get_frame_flags(fc.c, cf, C.int(fs)))
 }
 
+func (fc *FilterContext) Class() *Class {
+	return newClassFromC(unsafe.Pointer(fc.c))
+}
+
 func (fc *FilterContext) NbInputs() int {
 	return int(fc.c.nb_inputs)
 }
diff --git a/filter_graph.go b/filter_graph.go
index 1a7e482..2d8c783 100644
--- a/filter_graph.go
+++ b/filter_graph.go
@@ -17,21 +17,32 @@ func newFilterGraphFromC(c *C.struct_AVFilterGraph) *FilterGraph {
 	if c == nil {
 		return nil
 	}
-	return &FilterGraph{c: c}
+	g := &FilterGraph{c: c}
+	classers.set(g)
+	return g
 }
 
+var _ Classer = (*FilterGraph)(nil)
+
 func AllocFilterGraph() *FilterGraph {
 	return newFilterGraphFromC(C.avfilter_graph_alloc())
 }
 
 func (g *FilterGraph) Free() {
-	C.avfilter_graph_free(&g.c)
+	classers.del(g)
+	if g.c != nil {
+		C.avfilter_graph_free(&g.c)
+	}
 }
 
 func (g *FilterGraph) String() string {
 	return C.GoString(C.avfilter_graph_dump(g.c, nil))
 }
 
+func (g *FilterGraph) Class() *Class {
+	return newClassFromC(unsafe.Pointer(g.c))
+}
+
 type FilterArgs map[string]string
 
 func (args FilterArgs) String() string {
@@ -50,9 +61,11 @@ func (g *FilterGraph) NewFilterContext(f *Filter, name string, args FilterArgs)
 	}
 	cn := C.CString(name)
 	defer C.free(unsafe.Pointer(cn))
-	fc := newFilterContext()
-	err := newError(C.avfilter_graph_create_filter(&fc.c, f.c, cn, ca, nil, g.c))
-	return fc, err
+	var c *C.struct_AVFilterContext
+	if err := newError(C.avfilter_graph_create_filter(&c, f.c, cn, ca, nil, g.c)); err != nil {
+		return nil, err
+	}
+	return newFilterContext(c), nil
 }
 
 func (g *FilterGraph) Parse(content string, inputs, outputs *FilterInOut) error {
diff --git a/filter_graph_test.go b/filter_graph_test.go
index 8509b11..46d750d 100644
--- a/filter_graph_test.go
+++ b/filter_graph_test.go
@@ -1,48 +1,53 @@
 // TODO Fix https://github.com/asticode/go-astiav/actions/runs/5853322732/job/15867145888
 //go:build !windows
 
-package astiav_test
+package astiav
 
 import (
 	"fmt"
 	"strconv"
 	"testing"
 
-	"github.com/asticode/go-astiav"
 	"github.com/stretchr/testify/require"
 )
 
 func TestFilterGraph(t *testing.T) {
-	fg := astiav.AllocFilterGraph()
+	fg := AllocFilterGraph()
 	defer fg.Free()
+	cl := fg.Class()
+	require.NotNil(t, cl)
+	require.Equal(t, "AVFilterGraph", cl.Name())
 
-	bufferSink := astiav.FindFilterByName("buffersink")
+	bufferSink := FindFilterByName("buffersink")
 	require.NotNil(t, bufferSink)
 
 	fcOut, err := fg.NewFilterContext(bufferSink, "filter_out", nil)
 	require.NoError(t, err)
 	defer fcOut.Free()
+	cl = fcOut.Class()
+	require.NotNil(t, cl)
+	require.Equal(t, "AVFilter", cl.Name())
 
-	inputs := astiav.AllocFilterInOut()
+	inputs := AllocFilterInOut()
 	defer inputs.Free()
 	inputs.SetName("out")
 	inputs.SetFilterContext(fcOut)
 	inputs.SetPadIdx(0)
 	inputs.SetNext(nil)
 
-	var outputs *astiav.FilterInOut
+	var outputs *FilterInOut
 	defer func() {
 		if outputs != nil {
 			outputs.Free()
 		}
 	}()
-	var fcIns []*astiav.FilterContext
+	var fcIns []*FilterContext
 	for i := 0; i < 2; i++ {
-		bufferSrc := astiav.FindFilterByName("buffer")
+		bufferSrc := FindFilterByName("buffer")
 		require.NotNil(t, bufferSrc)
 
-		fcIn, err := fg.NewFilterContext(bufferSrc, fmt.Sprintf("filter_in_%d", i+1), astiav.FilterArgs{
-			"pix_fmt":      strconv.Itoa(int(astiav.PixelFormatYuv420P)),
+		fcIn, err := fg.NewFilterContext(bufferSrc, fmt.Sprintf("filter_in_%d", i+1), FilterArgs{
+			"pix_fmt":      strconv.Itoa(int(PixelFormatYuv420P)),
 			"pixel_aspect": "1/1",
 			"time_base":    "1/1000",
 			"video_size":   "1x1",
@@ -51,7 +56,7 @@ func TestFilterGraph(t *testing.T) {
 		fcIns = append(fcIns, fcIn)
 		defer fcIn.Free()
 
-		o := astiav.AllocFilterInOut()
+		o := AllocFilterInOut()
 		o.SetName(fmt.Sprintf("input_%d", i+1))
 		o.SetFilterContext(fcIn)
 		o.SetPadIdx(0)
@@ -68,19 +73,19 @@ func TestFilterGraph(t *testing.T) {
 
 	require.Equal(t, 1, fcOut.NbInputs())
 	require.Equal(t, 1, len(fcOut.Inputs()))
-	require.Equal(t, astiav.NewRational(1, 1000), fcOut.Inputs()[0].TimeBase())
+	require.Equal(t, NewRational(1, 1000), fcOut.Inputs()[0].TimeBase())
 	require.Equal(t, 0, fcOut.NbOutputs())
 	for _, fc := range fcIns {
 		require.Equal(t, 0, fc.NbInputs())
 		require.Equal(t, 1, fc.NbOutputs())
 		require.Equal(t, 1, len(fc.Outputs()))
-		require.Equal(t, astiav.NewRational(1, 1000), fc.Outputs()[0].TimeBase())
+		require.Equal(t, NewRational(1, 1000), fc.Outputs()[0].TimeBase())
 	}
 
-	resp, err := fg.SendCommand("scale", "invalid", "a", astiav.NewFilterCommandFlags())
+	resp, err := fg.SendCommand("scale", "invalid", "a", NewFilterCommandFlags())
 	require.Error(t, err)
 	require.Empty(t, resp)
-	resp, err = fg.SendCommand("scale", "width", "4", astiav.NewFilterCommandFlags().Add(astiav.FilterCommandFlagOne))
+	resp, err = fg.SendCommand("scale", "width", "4", NewFilterCommandFlags().Add(FilterCommandFlagOne))
 	require.NoError(t, err)
 	require.Empty(t, resp)
 
diff --git a/filter_test.go b/filter_test.go
index cb24286..82c7e50 100644
--- a/filter_test.go
+++ b/filter_test.go
@@ -1,14 +1,13 @@
-package astiav_test
+package astiav
 
 import (
 	"testing"
 
-	"github.com/asticode/go-astiav"
 	"github.com/stretchr/testify/require"
 )
 
 func TestFilter(t *testing.T) {
-	f := astiav.FindFilterByName("format")
+	f := FindFilterByName("format")
 	require.NotNil(t, f)
 	require.Equal(t, "format", f.Name())
 	require.Equal(t, "format", f.String())
diff --git a/flags_test.go b/flags_test.go
index d6189cf..cc7acfd 100644
--- a/flags_test.go
+++ b/flags_test.go
@@ -1,152 +1,151 @@
 // Code generated by astiav. DO NOT EDIT.
-package astiav_test
+package astiav
 import (
 	"testing"
 
-	"github.com/asticode/go-astiav"
 	"github.com/stretchr/testify/require"
 )
 
 func TestBuffersinkFlags(t *testing.T) {
-	fs := astiav.NewBuffersinkFlags(astiav.BuffersinkFlag(1))
-	require.True(t, fs.Has(astiav.BuffersinkFlag(1)))
-	fs = fs.Add(astiav.BuffersinkFlag(2))
-	require.True(t, fs.Has(astiav.BuffersinkFlag(2)))
-	fs = fs.Del(astiav.BuffersinkFlag(2))
-	require.False(t, fs.Has(astiav.BuffersinkFlag(2)))
+	fs := NewBuffersinkFlags(BuffersinkFlag(1))
+	require.True(t, fs.Has(BuffersinkFlag(1)))
+	fs = fs.Add(BuffersinkFlag(2))
+	require.True(t, fs.Has(BuffersinkFlag(2)))
+	fs = fs.Del(BuffersinkFlag(2))
+	require.False(t, fs.Has(BuffersinkFlag(2)))
 }
 
 func TestBuffersrcFlags(t *testing.T) {
-	fs := astiav.NewBuffersrcFlags(astiav.BuffersrcFlag(1))
-	require.True(t, fs.Has(astiav.BuffersrcFlag(1)))
-	fs = fs.Add(astiav.BuffersrcFlag(2))
-	require.True(t, fs.Has(astiav.BuffersrcFlag(2)))
-	fs = fs.Del(astiav.BuffersrcFlag(2))
-	require.False(t, fs.Has(astiav.BuffersrcFlag(2)))
+	fs := NewBuffersrcFlags(BuffersrcFlag(1))
+	require.True(t, fs.Has(BuffersrcFlag(1)))
+	fs = fs.Add(BuffersrcFlag(2))
+	require.True(t, fs.Has(BuffersrcFlag(2)))
+	fs = fs.Del(BuffersrcFlag(2))
+	require.False(t, fs.Has(BuffersrcFlag(2)))
 }
 
 func TestCodecContextFlags(t *testing.T) {
-	fs := astiav.NewCodecContextFlags(astiav.CodecContextFlag(1))
-	require.True(t, fs.Has(astiav.CodecContextFlag(1)))
-	fs = fs.Add(astiav.CodecContextFlag(2))
-	require.True(t, fs.Has(astiav.CodecContextFlag(2)))
-	fs = fs.Del(astiav.CodecContextFlag(2))
-	require.False(t, fs.Has(astiav.CodecContextFlag(2)))
+	fs := NewCodecContextFlags(CodecContextFlag(1))
+	require.True(t, fs.Has(CodecContextFlag(1)))
+	fs = fs.Add(CodecContextFlag(2))
+	require.True(t, fs.Has(CodecContextFlag(2)))
+	fs = fs.Del(CodecContextFlag(2))
+	require.False(t, fs.Has(CodecContextFlag(2)))
 }
 
 func TestCodecContextFlags2(t *testing.T) {
-	fs := astiav.NewCodecContextFlags2(astiav.CodecContextFlag2(1))
-	require.True(t, fs.Has(astiav.CodecContextFlag2(1)))
-	fs = fs.Add(astiav.CodecContextFlag2(2))
-	require.True(t, fs.Has(astiav.CodecContextFlag2(2)))
-	fs = fs.Del(astiav.CodecContextFlag2(2))
-	require.False(t, fs.Has(astiav.CodecContextFlag2(2)))
+	fs := NewCodecContextFlags2(CodecContextFlag2(1))
+	require.True(t, fs.Has(CodecContextFlag2(1)))
+	fs = fs.Add(CodecContextFlag2(2))
+	require.True(t, fs.Has(CodecContextFlag2(2)))
+	fs = fs.Del(CodecContextFlag2(2))
+	require.False(t, fs.Has(CodecContextFlag2(2)))
 }
 
 func TestCodecHardwareConfigMethodFlags(t *testing.T) {
-	fs := astiav.NewCodecHardwareConfigMethodFlags(astiav.CodecHardwareConfigMethodFlag(1))
-	require.True(t, fs.Has(astiav.CodecHardwareConfigMethodFlag(1)))
-	fs = fs.Add(astiav.CodecHardwareConfigMethodFlag(2))
-	require.True(t, fs.Has(astiav.CodecHardwareConfigMethodFlag(2)))
-	fs = fs.Del(astiav.CodecHardwareConfigMethodFlag(2))
-	require.False(t, fs.Has(astiav.CodecHardwareConfigMethodFlag(2)))
+	fs := NewCodecHardwareConfigMethodFlags(CodecHardwareConfigMethodFlag(1))
+	require.True(t, fs.Has(CodecHardwareConfigMethodFlag(1)))
+	fs = fs.Add(CodecHardwareConfigMethodFlag(2))
+	require.True(t, fs.Has(CodecHardwareConfigMethodFlag(2)))
+	fs = fs.Del(CodecHardwareConfigMethodFlag(2))
+	require.False(t, fs.Has(CodecHardwareConfigMethodFlag(2)))
 }
 
 func TestDictionaryFlags(t *testing.T) {
-	fs := astiav.NewDictionaryFlags(astiav.DictionaryFlag(1))
-	require.True(t, fs.Has(astiav.DictionaryFlag(1)))
-	fs = fs.Add(astiav.DictionaryFlag(2))
-	require.True(t, fs.Has(astiav.DictionaryFlag(2)))
-	fs = fs.Del(astiav.DictionaryFlag(2))
-	require.False(t, fs.Has(astiav.DictionaryFlag(2)))
+	fs := NewDictionaryFlags(DictionaryFlag(1))
+	require.True(t, fs.Has(DictionaryFlag(1)))
+	fs = fs.Add(DictionaryFlag(2))
+	require.True(t, fs.Has(DictionaryFlag(2)))
+	fs = fs.Del(DictionaryFlag(2))
+	require.False(t, fs.Has(DictionaryFlag(2)))
 }
 
 func TestFilterCommandFlags(t *testing.T) {
-	fs := astiav.NewFilterCommandFlags(astiav.FilterCommandFlag(1))
-	require.True(t, fs.Has(astiav.FilterCommandFlag(1)))
-	fs = fs.Add(astiav.FilterCommandFlag(2))
-	require.True(t, fs.Has(astiav.FilterCommandFlag(2)))
-	fs = fs.Del(astiav.FilterCommandFlag(2))
-	require.False(t, fs.Has(astiav.FilterCommandFlag(2)))
+	fs := NewFilterCommandFlags(FilterCommandFlag(1))
+	require.True(t, fs.Has(FilterCommandFlag(1)))
+	fs = fs.Add(FilterCommandFlag(2))
+	require.True(t, fs.Has(FilterCommandFlag(2)))
+	fs = fs.Del(FilterCommandFlag(2))
+	require.False(t, fs.Has(FilterCommandFlag(2)))
 }
 
 func TestFormatContextFlags(t *testing.T) {
-	fs := astiav.NewFormatContextFlags(astiav.FormatContextFlag(1))
-	require.True(t, fs.Has(astiav.FormatContextFlag(1)))
-	fs = fs.Add(astiav.FormatContextFlag(2))
-	require.True(t, fs.Has(astiav.FormatContextFlag(2)))
-	fs = fs.Del(astiav.FormatContextFlag(2))
-	require.False(t, fs.Has(astiav.FormatContextFlag(2)))
+	fs := NewFormatContextFlags(FormatContextFlag(1))
+	require.True(t, fs.Has(FormatContextFlag(1)))
+	fs = fs.Add(FormatContextFlag(2))
+	require.True(t, fs.Has(FormatContextFlag(2)))
+	fs = fs.Del(FormatContextFlag(2))
+	require.False(t, fs.Has(FormatContextFlag(2)))
 }
 
 func TestFormatContextCtxFlags(t *testing.T) {
-	fs := astiav.NewFormatContextCtxFlags(astiav.FormatContextCtxFlag(1))
-	require.True(t, fs.Has(astiav.FormatContextCtxFlag(1)))
-	fs = fs.Add(astiav.FormatContextCtxFlag(2))
-	require.True(t, fs.Has(astiav.FormatContextCtxFlag(2)))
-	fs = fs.Del(astiav.FormatContextCtxFlag(2))
-	require.False(t, fs.Has(astiav.FormatContextCtxFlag(2)))
+	fs := NewFormatContextCtxFlags(FormatContextCtxFlag(1))
+	require.True(t, fs.Has(FormatContextCtxFlag(1)))
+	fs = fs.Add(FormatContextCtxFlag(2))
+	require.True(t, fs.Has(FormatContextCtxFlag(2)))
+	fs = fs.Del(FormatContextCtxFlag(2))
+	require.False(t, fs.Has(FormatContextCtxFlag(2)))
 }
 
 func TestFormatEventFlags(t *testing.T) {
-	fs := astiav.NewFormatEventFlags(astiav.FormatEventFlag(1))
-	require.True(t, fs.Has(astiav.FormatEventFlag(1)))
-	fs = fs.Add(astiav.FormatEventFlag(2))
-	require.True(t, fs.Has(astiav.FormatEventFlag(2)))
-	fs = fs.Del(astiav.FormatEventFlag(2))
-	require.False(t, fs.Has(astiav.FormatEventFlag(2)))
+	fs := NewFormatEventFlags(FormatEventFlag(1))
+	require.True(t, fs.Has(FormatEventFlag(1)))
+	fs = fs.Add(FormatEventFlag(2))
+	require.True(t, fs.Has(FormatEventFlag(2)))
+	fs = fs.Del(FormatEventFlag(2))
+	require.False(t, fs.Has(FormatEventFlag(2)))
 }
 
 func TestIOContextFlags(t *testing.T) {
-	fs := astiav.NewIOContextFlags(astiav.IOContextFlag(1))
-	require.True(t, fs.Has(astiav.IOContextFlag(1)))
-	fs = fs.Add(astiav.IOContextFlag(2))
-	require.True(t, fs.Has(astiav.IOContextFlag(2)))
-	fs = fs.Del(astiav.IOContextFlag(2))
-	require.False(t, fs.Has(astiav.IOContextFlag(2)))
+	fs := NewIOContextFlags(IOContextFlag(1))
+	require.True(t, fs.Has(IOContextFlag(1)))
+	fs = fs.Add(IOContextFlag(2))
+	require.True(t, fs.Has(IOContextFlag(2)))
+	fs = fs.Del(IOContextFlag(2))
+	require.False(t, fs.Has(IOContextFlag(2)))
 }
 
 func TestIOFormatFlags(t *testing.T) {
-	fs := astiav.NewIOFormatFlags(astiav.IOFormatFlag(1))
-	require.True(t, fs.Has(astiav.IOFormatFlag(1)))
-	fs = fs.Add(astiav.IOFormatFlag(2))
-	require.True(t, fs.Has(astiav.IOFormatFlag(2)))
-	fs = fs.Del(astiav.IOFormatFlag(2))
-	require.False(t, fs.Has(astiav.IOFormatFlag(2)))
+	fs := NewIOFormatFlags(IOFormatFlag(1))
+	require.True(t, fs.Has(IOFormatFlag(1)))
+	fs = fs.Add(IOFormatFlag(2))
+	require.True(t, fs.Has(IOFormatFlag(2)))
+	fs = fs.Del(IOFormatFlag(2))
+	require.False(t, fs.Has(IOFormatFlag(2)))
 }
 
 func TestPacketFlags(t *testing.T) {
-	fs := astiav.NewPacketFlags(astiav.PacketFlag(1))
-	require.True(t, fs.Has(astiav.PacketFlag(1)))
-	fs = fs.Add(astiav.PacketFlag(2))
-	require.True(t, fs.Has(astiav.PacketFlag(2)))
-	fs = fs.Del(astiav.PacketFlag(2))
-	require.False(t, fs.Has(astiav.PacketFlag(2)))
+	fs := NewPacketFlags(PacketFlag(1))
+	require.True(t, fs.Has(PacketFlag(1)))
+	fs = fs.Add(PacketFlag(2))
+	require.True(t, fs.Has(PacketFlag(2)))
+	fs = fs.Del(PacketFlag(2))
+	require.False(t, fs.Has(PacketFlag(2)))
 }
 
 func TestSeekFlags(t *testing.T) {
-	fs := astiav.NewSeekFlags(astiav.SeekFlag(1))
-	require.True(t, fs.Has(astiav.SeekFlag(1)))
-	fs = fs.Add(astiav.SeekFlag(2))
-	require.True(t, fs.Has(astiav.SeekFlag(2)))
-	fs = fs.Del(astiav.SeekFlag(2))
-	require.False(t, fs.Has(astiav.SeekFlag(2)))
+	fs := NewSeekFlags(SeekFlag(1))
+	require.True(t, fs.Has(SeekFlag(1)))
+	fs = fs.Add(SeekFlag(2))
+	require.True(t, fs.Has(SeekFlag(2)))
+	fs = fs.Del(SeekFlag(2))
+	require.False(t, fs.Has(SeekFlag(2)))
 }
 
 func TestSoftwareScaleContextFlags(t *testing.T) {
-	fs := astiav.NewSoftwareScaleContextFlags(astiav.SoftwareScaleContextFlag(1))
-	require.True(t, fs.Has(astiav.SoftwareScaleContextFlag(1)))
-	fs = fs.Add(astiav.SoftwareScaleContextFlag(2))
-	require.True(t, fs.Has(astiav.SoftwareScaleContextFlag(2)))
-	fs = fs.Del(astiav.SoftwareScaleContextFlag(2))
-	require.False(t, fs.Has(astiav.SoftwareScaleContextFlag(2)))
+	fs := NewSoftwareScaleContextFlags(SoftwareScaleContextFlag(1))
+	require.True(t, fs.Has(SoftwareScaleContextFlag(1)))
+	fs = fs.Add(SoftwareScaleContextFlag(2))
+	require.True(t, fs.Has(SoftwareScaleContextFlag(2)))
+	fs = fs.Del(SoftwareScaleContextFlag(2))
+	require.False(t, fs.Has(SoftwareScaleContextFlag(2)))
 }
 
 func TestStreamEventFlags(t *testing.T) {
-	fs := astiav.NewStreamEventFlags(astiav.StreamEventFlag(1))
-	require.True(t, fs.Has(astiav.StreamEventFlag(1)))
-	fs = fs.Add(astiav.StreamEventFlag(2))
-	require.True(t, fs.Has(astiav.StreamEventFlag(2)))
-	fs = fs.Del(astiav.StreamEventFlag(2))
-	require.False(t, fs.Has(astiav.StreamEventFlag(2)))
+	fs := NewStreamEventFlags(StreamEventFlag(1))
+	require.True(t, fs.Has(StreamEventFlag(1)))
+	fs = fs.Add(StreamEventFlag(2))
+	require.True(t, fs.Has(StreamEventFlag(2)))
+	fs = fs.Del(StreamEventFlag(2))
+	require.False(t, fs.Has(StreamEventFlag(2)))
 }
diff --git a/format_context.go b/format_context.go
index fbdc59b..acbe367 100644
--- a/format_context.go
+++ b/format_context.go
@@ -29,22 +29,22 @@ type FormatContext struct {
 	c *C.struct_AVFormatContext
 }
 
-func newFormatContext() *FormatContext {
-	return &FormatContext{}
-}
-
 func newFormatContextFromC(c *C.struct_AVFormatContext) *FormatContext {
 	if c == nil {
 		return nil
 	}
-	return &FormatContext{c: c}
+	fc := &FormatContext{c: c}
+	classers.set(fc)
+	return fc
 }
 
+var _ Classer = (*FormatContext)(nil)
+
 func AllocFormatContext() *FormatContext {
 	return newFormatContextFromC(C.avformat_alloc_context())
 }
 
-func AllocOutputFormatContext(o *OutputFormat, formatName, filename string) (*FormatContext, error) {
+func AllocOutputFormatContext(of *OutputFormat, formatName, filename string) (*FormatContext, error) {
 	fonc := (*C.char)(nil)
 	if len(formatName) > 0 {
 		fonc = C.CString(formatName)
@@ -55,19 +55,30 @@ func AllocOutputFormatContext(o *OutputFormat, formatName, filename string) (*Fo
 		finc = C.CString(filename)
 		defer C.free(unsafe.Pointer(finc))
 	}
-	fc := newFormatContext()
-	var oc *C.struct_AVOutputFormat
-	if o != nil {
-		oc = o.c
+	var ofc *C.struct_AVOutputFormat
+	if of != nil {
+		ofc = of.c
 	}
-	err := newError(C.avformat_alloc_output_context2(&fc.c, oc, fonc, finc))
-	return fc, err
+	var fcc *C.struct_AVFormatContext
+	if err := newError(C.avformat_alloc_output_context2(&fcc, ofc, fonc, finc)); err != nil {
+		return nil, err
+	}
+	return newFormatContextFromC(fcc), nil
+}
+
+func (fc *FormatContext) Free() {
+	classers.del(fc)
+	C.avformat_free_context(fc.c)
 }
 
 func (fc *FormatContext) BitRate() int64 {
 	return int64(fc.c.bit_rate)
 }
 
+func (fc *FormatContext) Class() *Class {
+	return newClassFromC(unsafe.Pointer(fc.c))
+}
+
 func (fc *FormatContext) CtxFlags() FormatContextCtxFlags {
 	return FormatContextCtxFlags(fc.c.ctx_flags)
 }
@@ -115,6 +126,13 @@ func (fc *FormatContext) OutputFormat() *OutputFormat {
 }
 
 func (fc *FormatContext) Pb() *IOContext {
+	// If the io context has been created using the format context's OpenInput() method, we need to
+	// make sure to return the same go struct as the one stored in classers
+	if c, ok := classers.get(unsafe.Pointer(fc.c.pb)); ok {
+		if v, ok := c.(*IOContext); ok {
+			return v
+		}
+	}
 	return newIOContextFromC(fc.c.pb)
 }
 
@@ -153,15 +171,23 @@ func (fc *FormatContext) OpenInput(url string, fmt *InputFormat, d *Dictionary)
 	if fmt != nil {
 		fmtc = fmt.c
 	}
-	return newError(C.avformat_open_input(&fc.c, urlc, fmtc, dc))
+	if err := newError(C.avformat_open_input(&fc.c, urlc, fmtc, dc)); err != nil {
+		return err
+	}
+	if pb := fc.Pb(); pb != nil {
+		classers.set(pb)
+	}
+	return nil
 }
 
 func (fc *FormatContext) CloseInput() {
-	C.avformat_close_input(&fc.c)
-}
-
-func (fc *FormatContext) Free() {
-	C.avformat_free_context(fc.c)
+	if pb := fc.Pb(); pb != nil {
+		classers.del(pb)
+	}
+	classers.del(fc)
+	if fc.c != nil {
+		C.avformat_close_input(&fc.c)
+	}
 }
 
 func (fc *FormatContext) NewStream(c *Codec) *Stream {
diff --git a/format_context_test.go b/format_context_test.go
index a7dd16c..7fe986a 100644
--- a/format_context_test.go
+++ b/format_context_test.go
@@ -1,9 +1,8 @@
-package astiav_test
+package astiav
 
 import (
 	"testing"
 
-	"github.com/asticode/go-astiav"
 	"github.com/stretchr/testify/require"
 )
 
@@ -15,40 +14,42 @@ func TestFormatContext(t *testing.T) {
 	s1 := ss[0]
 
 	require.Equal(t, int64(607583), fc1.BitRate())
-	require.Equal(t, astiav.NewFormatContextCtxFlags(0), fc1.CtxFlags())
+	require.Equal(t, NewFormatContextCtxFlags(0), fc1.CtxFlags())
 	require.Equal(t, int64(5014000), fc1.Duration())
-	require.True(t, fc1.EventFlags().Has(astiav.FormatEventFlagMetadataUpdated))
-	require.True(t, fc1.Flags().Has(astiav.FormatContextFlagAutoBsf))
-	require.Equal(t, astiav.NewRational(24, 1), fc1.GuessFrameRate(s1, nil))
-	require.Equal(t, astiav.NewRational(1, 1), fc1.GuessSampleAspectRatio(s1, nil))
-	require.True(t, fc1.InputFormat().Flags().Has(astiav.IOFormatFlagNoByteSeek))
-	require.Equal(t, astiav.IOContextFlags(0), fc1.IOFlags())
+	require.True(t, fc1.EventFlags().Has(FormatEventFlagMetadataUpdated))
+	require.True(t, fc1.Flags().Has(FormatContextFlagAutoBsf))
+	require.Equal(t, NewRational(24, 1), fc1.GuessFrameRate(s1, nil))
+	require.Equal(t, NewRational(1, 1), fc1.GuessSampleAspectRatio(s1, nil))
+	require.True(t, fc1.InputFormat().Flags().Has(IOFormatFlagNoByteSeek))
+	require.Equal(t, IOContextFlags(0), fc1.IOFlags())
 	require.Equal(t, int64(0), fc1.MaxAnalyzeDuration())
-	require.Equal(t, "isom", fc1.Metadata().Get("major_brand", nil, astiav.NewDictionaryFlags()).Value())
+	require.Equal(t, "isom", fc1.Metadata().Get("major_brand", nil, NewDictionaryFlags()).Value())
 	require.Equal(t, int64(0), fc1.StartTime())
 	require.Equal(t, 2, fc1.NbStreams())
 	require.Len(t, fc1.Streams(), 2)
+	cl := fc1.Class()
+	require.NotNil(t, cl)
+	require.Equal(t, "AVFormatContext", cl.Name())
 
 	sdp, err := fc1.SDPCreate()
 	require.NoError(t, err)
 	require.Equal(t, "v=0\r\no=- 0 0 IN IP4 127.0.0.1\r\ns=Big Buck Bunny\r\nt=0 0\r\na=tool:libavformat LIBAVFORMAT_VERSION\r\nm=video 0 RTP/AVP 96\r\nb=AS:441\r\na=rtpmap:96 H264/90000\r\na=fmtp:96 packetization-mode=1; sprop-parameter-sets=Z0LADasgKDPz4CIAAAMAAgAAAwBhHihUkA==,aM48gA==; profile-level-id=42C00D\r\na=control:streamid=0\r\nm=audio 0 RTP/AVP 97\r\nb=AS:161\r\na=rtpmap:97 MPEG4-GENERIC/48000/2\r\na=fmtp:97 profile-level-id=1;mode=AAC-hbr;sizelength=13;indexlength=3;indexdeltalength=3; config=1190\r\na=control:streamid=1\r\n", sdp)
 
-	fc2, err := astiav.AllocOutputFormatContext(nil, "", "/tmp/test.mp4")
+	fc2, err := AllocOutputFormatContext(nil, "", "/tmp/test.mp4")
 	require.NoError(t, err)
 	defer fc2.Free()
-	require.True(t, fc2.OutputFormat().Flags().Has(astiav.IOFormatFlagGlobalheader))
+	require.True(t, fc2.OutputFormat().Flags().Has(IOFormatFlagGlobalheader))
 
-	fc3 := astiav.AllocFormatContext()
+	fc3 := AllocFormatContext()
 	require.NotNil(t, fc3)
 	defer fc3.Free()
-	c := astiav.NewIOContext()
-	err = c.Open("testdata/video.mp4", astiav.NewIOContextFlags(astiav.IOContextFlagRead))
+	c, err := OpenIOContext("testdata/video.mp4", NewIOContextFlags(IOContextFlagRead))
 	require.NoError(t, err)
 	defer c.Closep() //nolint:errcheck
 	fc3.SetPb(c)
-	fc3.SetStrictStdCompliance(astiav.StrictStdComplianceExperimental)
+	fc3.SetStrictStdCompliance(StrictStdComplianceExperimental)
 	require.NotNil(t, fc3.Pb())
-	require.Equal(t, astiav.StrictStdComplianceExperimental, fc3.StrictStdCompliance())
+	require.Equal(t, StrictStdComplianceExperimental, fc3.StrictStdCompliance())
 	s2 := fc3.NewStream(nil)
 	require.NotNil(t, s2)
 	s3 := fc3.NewStream(nil)
diff --git a/frame.go b/frame.go
index 289041c..17c6edb 100644
--- a/frame.go
+++ b/frame.go
@@ -214,6 +214,6 @@ func (f *Frame) MoveRef(src *Frame) {
 	C.av_frame_move_ref(f.c, src.c)
 }
 
-func (f *Frame) UnsafePointer() *C.struct_AVFrame {
+func (f *Frame) UnsafeTypedPointer() *C.struct_AVFrame {
 	return f.c
 }
diff --git a/frame_data_internal_test.go b/frame_data_internal_test.go
deleted file mode 100644
index 34c0264..0000000
--- a/frame_data_internal_test.go
+++ /dev/null
@@ -1,285 +0,0 @@
-package astiav
-
-import (
-	"image"
-	"testing"
-
-	"github.com/stretchr/testify/require"
-)
-
-type mockedFrameDataFrame struct {
-	h           int
-	imageBytes  []byte
-	linesizes   []int
-	pf          PixelFormat
-	planesBytes [][]byte
-	w           int
-}
-
-var _ frameDataFramer = (*mockedFrameDataFrame)(nil)
-
-func (f *mockedFrameDataFrame) height() int {
-	return f.h
-}
-
-func (f *mockedFrameDataFrame) imageBufferSize(align int) (int, error) {
-	return len(f.imageBytes), nil
-}
-
-func (f *mockedFrameDataFrame) imageCopyToBuffer(b []byte, align int) (int, error) {
-	copy(b, f.imageBytes)
-	return len(f.imageBytes), nil
-}
-
-func (f *mockedFrameDataFrame) linesize(i int) int {
-	return f.linesizes[i]
-}
-
-func (f *mockedFrameDataFrame) pixelFormat() PixelFormat {
-	return f.pf
-}
-
-func (f *mockedFrameDataFrame) planeBytes(i int) []byte {
-	return f.planesBytes[i]
-}
-
-func (f *mockedFrameDataFrame) width() int {
-	return f.w
-}
-
-func TestFrameDataInternal(t *testing.T) {
-	fdf := &mockedFrameDataFrame{}
-	fd := newFrameData(fdf)
-
-	for _, v := range []struct {
-		err bool
-		i   image.Image
-		pfs []PixelFormat
-	}{
-		{
-			i:   &image.Gray{},
-			pfs: []PixelFormat{PixelFormatGray8},
-		},
-		{
-			i:   &image.Gray16{},
-			pfs: []PixelFormat{PixelFormatGray16Be},
-		},
-		{
-			i: &image.RGBA{},
-			pfs: []PixelFormat{
-				PixelFormatRgb0,
-				PixelFormat0Rgb,
-				PixelFormatRgb4,
-				PixelFormatRgb8,
-			},
-		},
-		{
-			i:   &image.NRGBA{},
-			pfs: []PixelFormat{PixelFormatRgba},
-		},
-		{
-			i:   &image.NRGBA64{},
-			pfs: []PixelFormat{PixelFormatRgba64Be},
-		},
-		{
-			i: &image.NYCbCrA{},
-			pfs: []PixelFormat{
-				PixelFormatYuva420P,
-				PixelFormatYuva422P,
-				PixelFormatYuva444P,
-			},
-		},
-		{
-			i: &image.YCbCr{},
-			pfs: []PixelFormat{
-				PixelFormatYuv410P,
-				PixelFormatYuv411P,
-				PixelFormatYuvj411P,
-				PixelFormatYuv420P,
-				PixelFormatYuvj420P,
-				PixelFormatYuv422P,
-				PixelFormatYuvj422P,
-				PixelFormatYuv440P,
-				PixelFormatYuvj440P,
-				PixelFormatYuv444P,
-				PixelFormatYuvj444P,
-			},
-		},
-		{
-			err: true,
-			pfs: []PixelFormat{PixelFormatAbgr},
-		},
-	} {
-		for _, pf := range v.pfs {
-			fdf.pf = pf
-			i, err := fd.GuessImageFormat()
-			if v.err {
-				require.Error(t, err)
-			} else {
-				require.IsType(t, v.i, i)
-			}
-		}
-	}
-
-	fdf.imageBytes = []byte{0, 1, 2, 3}
-	_, err := fd.Bytes(0)
-	require.Error(t, err)
-	fdf.h = 1
-	fdf.w = 2
-	b, err := fd.Bytes(0)
-	require.NoError(t, err)
-	require.Equal(t, fdf.imageBytes, b)
-
-	for _, v := range []struct {
-		e           image.Image
-		err         bool
-		i           image.Image
-		linesizes   []int
-		pixelFormat PixelFormat
-		planesBytes [][]byte
-	}{
-		{
-			e: &image.Alpha{
-				Pix:    []byte{0, 1, 2, 3},
-				Stride: 1,
-				Rect:   image.Rect(0, 0, 2, 1),
-			},
-			i:           &image.Alpha{},
-			linesizes:   []int{1},
-			pixelFormat: PixelFormatRgba,
-			planesBytes: [][]byte{{0, 1, 2, 3}},
-		},
-		{
-			e: &image.Alpha16{
-				Pix:    []byte{0, 1, 2, 3},
-				Stride: 1,
-				Rect:   image.Rect(0, 0, 2, 1),
-			},
-			i:           &image.Alpha16{},
-			linesizes:   []int{1},
-			pixelFormat: PixelFormatRgba,
-			planesBytes: [][]byte{{0, 1, 2, 3}},
-		},
-		{
-			e: &image.CMYK{
-				Pix:    []byte{0, 1, 2, 3},
-				Stride: 1,
-				Rect:   image.Rect(0, 0, 2, 1),
-			},
-			i:           &image.CMYK{},
-			linesizes:   []int{1},
-			pixelFormat: PixelFormatRgba,
-			planesBytes: [][]byte{{0, 1, 2, 3}},
-		},
-		{
-			e: &image.Gray{
-				Pix:    []byte{0, 1, 2, 3},
-				Stride: 1,
-				Rect:   image.Rect(0, 0, 2, 1),
-			},
-			i:           &image.Gray{},
-			linesizes:   []int{1},
-			pixelFormat: PixelFormatRgba,
-			planesBytes: [][]byte{{0, 1, 2, 3}},
-		},
-		{
-			e: &image.Gray16{
-				Pix:    []byte{0, 1, 2, 3},
-				Stride: 1,
-				Rect:   image.Rect(0, 0, 2, 1),
-			},
-			i:           &image.Gray16{},
-			linesizes:   []int{1},
-			pixelFormat: PixelFormatRgba,
-			planesBytes: [][]byte{{0, 1, 2, 3}},
-		},
-		{
-			e: &image.NRGBA{
-				Pix:    []byte{0, 1, 2, 3},
-				Stride: 1,
-				Rect:   image.Rect(0, 0, 2, 1),
-			},
-			i:           &image.NRGBA{},
-			linesizes:   []int{1},
-			pixelFormat: PixelFormatRgba,
-			planesBytes: [][]byte{{0, 1, 2, 3}},
-		},
-		{
-			e: &image.NRGBA64{
-				Pix:    []byte{0, 1, 2, 3},
-				Stride: 1,
-				Rect:   image.Rect(0, 0, 2, 1),
-			},
-			i:           &image.NRGBA64{},
-			linesizes:   []int{1},
-			pixelFormat: PixelFormatRgba,
-			planesBytes: [][]byte{{0, 1, 2, 3}},
-		},
-		{
-			e: &image.NYCbCrA{
-				A:       []byte{6, 7},
-				AStride: 4,
-				YCbCr: image.YCbCr{
-					Y:              []byte{0, 1},
-					Cb:             []byte{2, 3},
-					Cr:             []byte{4, 5},
-					YStride:        1,
-					CStride:        2,
-					SubsampleRatio: image.YCbCrSubsampleRatio444,
-					Rect:           image.Rect(0, 0, 2, 1),
-				},
-			},
-			i:           &image.NYCbCrA{},
-			linesizes:   []int{1, 2, 3, 4},
-			pixelFormat: PixelFormatYuv444P,
-			planesBytes: [][]byte{{0, 1}, {2, 3}, {4, 5}, {6, 7}},
-		},
-		{
-			e: &image.RGBA{
-				Pix:    []byte{0, 1, 2, 3},
-				Stride: 1,
-				Rect:   image.Rect(0, 0, 2, 1),
-			},
-			i:           &image.RGBA{},
-			linesizes:   []int{1},
-			pixelFormat: PixelFormatRgba,
-			planesBytes: [][]byte{{0, 1, 2, 3}},
-		},
-		{
-			e: &image.RGBA64{
-				Pix:    []byte{0, 1, 2, 3},
-				Stride: 1,
-				Rect:   image.Rect(0, 0, 2, 1),
-			},
-			i:           &image.RGBA64{},
-			linesizes:   []int{1},
-			pixelFormat: PixelFormatRgba,
-			planesBytes: [][]byte{{0, 1, 2, 3}},
-		},
-		{
-			e: &image.YCbCr{
-				Y:              []byte{0, 1},
-				Cb:             []byte{2, 3},
-				Cr:             []byte{4, 5},
-				YStride:        1,
-				CStride:        2,
-				SubsampleRatio: image.YCbCrSubsampleRatio420,
-				Rect:           image.Rect(0, 0, 2, 1),
-			},
-			i:           &image.YCbCr{},
-			linesizes:   []int{1, 2, 3},
-			pixelFormat: PixelFormatYuv420P,
-			planesBytes: [][]byte{{0, 1}, {2, 3}, {4, 5}},
-		},
-	} {
-		fdf.linesizes = v.linesizes
-		fdf.pf = v.pixelFormat
-		fdf.planesBytes = v.planesBytes
-		err = fd.ToImage(v.i)
-		if v.err {
-			require.Error(t, err)
-		} else {
-			require.Equal(t, v.e, v.i)
-		}
-	}
-}
diff --git a/frame_data_test.go b/frame_data_test.go
index fc9c12f..7621579 100644
--- a/frame_data_test.go
+++ b/frame_data_test.go
@@ -1,20 +1,297 @@
-package astiav_test
+package astiav
 
 import (
+	"image"
 	"image/png"
 	"os"
 	"testing"
 
-	"github.com/asticode/go-astiav"
 	"github.com/stretchr/testify/require"
 )
 
+type mockedFrameDataFrame struct {
+	h           int
+	imageBytes  []byte
+	linesizes   []int
+	pf          PixelFormat
+	planesBytes [][]byte
+	w           int
+}
+
+var _ frameDataFramer = (*mockedFrameDataFrame)(nil)
+
+func (f *mockedFrameDataFrame) height() int {
+	return f.h
+}
+
+func (f *mockedFrameDataFrame) imageBufferSize(align int) (int, error) {
+	return len(f.imageBytes), nil
+}
+
+func (f *mockedFrameDataFrame) imageCopyToBuffer(b []byte, align int) (int, error) {
+	copy(b, f.imageBytes)
+	return len(f.imageBytes), nil
+}
+
+func (f *mockedFrameDataFrame) linesize(i int) int {
+	return f.linesizes[i]
+}
+
+func (f *mockedFrameDataFrame) pixelFormat() PixelFormat {
+	return f.pf
+}
+
+func (f *mockedFrameDataFrame) planeBytes(i int) []byte {
+	return f.planesBytes[i]
+}
+
+func (f *mockedFrameDataFrame) width() int {
+	return f.w
+}
+
+func TestFrameDataInternal(t *testing.T) {
+	fdf := &mockedFrameDataFrame{}
+	fd := newFrameData(fdf)
+
+	for _, v := range []struct {
+		err bool
+		i   image.Image
+		pfs []PixelFormat
+	}{
+		{
+			i:   &image.Gray{},
+			pfs: []PixelFormat{PixelFormatGray8},
+		},
+		{
+			i:   &image.Gray16{},
+			pfs: []PixelFormat{PixelFormatGray16Be},
+		},
+		{
+			i: &image.RGBA{},
+			pfs: []PixelFormat{
+				PixelFormatRgb0,
+				PixelFormat0Rgb,
+				PixelFormatRgb4,
+				PixelFormatRgb8,
+			},
+		},
+		{
+			i:   &image.NRGBA{},
+			pfs: []PixelFormat{PixelFormatRgba},
+		},
+		{
+			i:   &image.NRGBA64{},
+			pfs: []PixelFormat{PixelFormatRgba64Be},
+		},
+		{
+			i: &image.NYCbCrA{},
+			pfs: []PixelFormat{
+				PixelFormatYuva420P,
+				PixelFormatYuva422P,
+				PixelFormatYuva444P,
+			},
+		},
+		{
+			i: &image.YCbCr{},
+			pfs: []PixelFormat{
+				PixelFormatYuv410P,
+				PixelFormatYuv411P,
+				PixelFormatYuvj411P,
+				PixelFormatYuv420P,
+				PixelFormatYuvj420P,
+				PixelFormatYuv422P,
+				PixelFormatYuvj422P,
+				PixelFormatYuv440P,
+				PixelFormatYuvj440P,
+				PixelFormatYuv444P,
+				PixelFormatYuvj444P,
+			},
+		},
+		{
+			err: true,
+			pfs: []PixelFormat{PixelFormatAbgr},
+		},
+	} {
+		for _, pf := range v.pfs {
+			fdf.pf = pf
+			i, err := fd.GuessImageFormat()
+			if v.err {
+				require.Error(t, err)
+			} else {
+				require.IsType(t, v.i, i)
+			}
+		}
+	}
+
+	fdf.imageBytes = []byte{0, 1, 2, 3}
+	_, err := fd.Bytes(0)
+	require.Error(t, err)
+	fdf.h = 1
+	fdf.w = 2
+	b, err := fd.Bytes(0)
+	require.NoError(t, err)
+	require.Equal(t, fdf.imageBytes, b)
+
+	for _, v := range []struct {
+		e           image.Image
+		err         bool
+		i           image.Image
+		linesizes   []int
+		pixelFormat PixelFormat
+		planesBytes [][]byte
+	}{
+		{
+			e: &image.Alpha{
+				Pix:    []byte{0, 1, 2, 3},
+				Stride: 1,
+				Rect:   image.Rect(0, 0, 2, 1),
+			},
+			i:           &image.Alpha{},
+			linesizes:   []int{1},
+			pixelFormat: PixelFormatRgba,
+			planesBytes: [][]byte{{0, 1, 2, 3}},
+		},
+		{
+			e: &image.Alpha16{
+				Pix:    []byte{0, 1, 2, 3},
+				Stride: 1,
+				Rect:   image.Rect(0, 0, 2, 1),
+			},
+			i:           &image.Alpha16{},
+			linesizes:   []int{1},
+			pixelFormat: PixelFormatRgba,
+			planesBytes: [][]byte{{0, 1, 2, 3}},
+		},
+		{
+			e: &image.CMYK{
+				Pix:    []byte{0, 1, 2, 3},
+				Stride: 1,
+				Rect:   image.Rect(0, 0, 2, 1),
+			},
+			i:           &image.CMYK{},
+			linesizes:   []int{1},
+			pixelFormat: PixelFormatRgba,
+			planesBytes: [][]byte{{0, 1, 2, 3}},
+		},
+		{
+			e: &image.Gray{
+				Pix:    []byte{0, 1, 2, 3},
+				Stride: 1,
+				Rect:   image.Rect(0, 0, 2, 1),
+			},
+			i:           &image.Gray{},
+			linesizes:   []int{1},
+			pixelFormat: PixelFormatRgba,
+			planesBytes: [][]byte{{0, 1, 2, 3}},
+		},
+		{
+			e: &image.Gray16{
+				Pix:    []byte{0, 1, 2, 3},
+				Stride: 1,
+				Rect:   image.Rect(0, 0, 2, 1),
+			},
+			i:           &image.Gray16{},
+			linesizes:   []int{1},
+			pixelFormat: PixelFormatRgba,
+			planesBytes: [][]byte{{0, 1, 2, 3}},
+		},
+		{
+			e: &image.NRGBA{
+				Pix:    []byte{0, 1, 2, 3},
+				Stride: 1,
+				Rect:   image.Rect(0, 0, 2, 1),
+			},
+			i:           &image.NRGBA{},
+			linesizes:   []int{1},
+			pixelFormat: PixelFormatRgba,
+			planesBytes: [][]byte{{0, 1, 2, 3}},
+		},
+		{
+			e: &image.NRGBA64{
+				Pix:    []byte{0, 1, 2, 3},
+				Stride: 1,
+				Rect:   image.Rect(0, 0, 2, 1),
+			},
+			i:           &image.NRGBA64{},
+			linesizes:   []int{1},
+			pixelFormat: PixelFormatRgba,
+			planesBytes: [][]byte{{0, 1, 2, 3}},
+		},
+		{
+			e: &image.NYCbCrA{
+				A:       []byte{6, 7},
+				AStride: 4,
+				YCbCr: image.YCbCr{
+					Y:              []byte{0, 1},
+					Cb:             []byte{2, 3},
+					Cr:             []byte{4, 5},
+					YStride:        1,
+					CStride:        2,
+					SubsampleRatio: image.YCbCrSubsampleRatio444,
+					Rect:           image.Rect(0, 0, 2, 1),
+				},
+			},
+			i:           &image.NYCbCrA{},
+			linesizes:   []int{1, 2, 3, 4},
+			pixelFormat: PixelFormatYuv444P,
+			planesBytes: [][]byte{{0, 1}, {2, 3}, {4, 5}, {6, 7}},
+		},
+		{
+			e: &image.RGBA{
+				Pix:    []byte{0, 1, 2, 3},
+				Stride: 1,
+				Rect:   image.Rect(0, 0, 2, 1),
+			},
+			i:           &image.RGBA{},
+			linesizes:   []int{1},
+			pixelFormat: PixelFormatRgba,
+			planesBytes: [][]byte{{0, 1, 2, 3}},
+		},
+		{
+			e: &image.RGBA64{
+				Pix:    []byte{0, 1, 2, 3},
+				Stride: 1,
+				Rect:   image.Rect(0, 0, 2, 1),
+			},
+			i:           &image.RGBA64{},
+			linesizes:   []int{1},
+			pixelFormat: PixelFormatRgba,
+			planesBytes: [][]byte{{0, 1, 2, 3}},
+		},
+		{
+			e: &image.YCbCr{
+				Y:              []byte{0, 1},
+				Cb:             []byte{2, 3},
+				Cr:             []byte{4, 5},
+				YStride:        1,
+				CStride:        2,
+				SubsampleRatio: image.YCbCrSubsampleRatio420,
+				Rect:           image.Rect(0, 0, 2, 1),
+			},
+			i:           &image.YCbCr{},
+			linesizes:   []int{1, 2, 3},
+			pixelFormat: PixelFormatYuv420P,
+			planesBytes: [][]byte{{0, 1}, {2, 3}, {4, 5}},
+		},
+	} {
+		fdf.linesizes = v.linesizes
+		fdf.pf = v.pixelFormat
+		fdf.planesBytes = v.planesBytes
+		err = fd.ToImage(v.i)
+		if v.err {
+			require.Error(t, err)
+		} else {
+			require.Equal(t, v.e, v.i)
+		}
+	}
+}
+
 func TestFrameData(t *testing.T) {
 	const (
 		name = "image-rgba"
 		ext  = "png"
 	)
-	f, err := globalHelper.inputLastFrame(name+"."+ext, astiav.MediaTypeVideo)
+	f, err := globalHelper.inputLastFrame(name+"."+ext, MediaTypeVideo)
 	require.NoError(t, err)
 	fd := f.Data()
 
diff --git a/frame_test.go b/frame_test.go
index a4f2fe9..98c175e 100644
--- a/frame_test.go
+++ b/frame_test.go
@@ -1,45 +1,44 @@
-package astiav_test
+package astiav
 
 import (
 	"bytes"
 	"testing"
 
-	"github.com/asticode/go-astiav"
 	"github.com/stretchr/testify/require"
 )
 
 func TestFrame(t *testing.T) {
-	f1, err := globalHelper.inputLastFrame("video.mp4", astiav.MediaTypeVideo)
+	f1, err := globalHelper.inputLastFrame("video.mp4", MediaTypeVideo)
 	require.NoError(t, err)
 	require.Equal(t, [8]int{384, 192, 192, 0, 0, 0, 0, 0}, f1.Linesize())
 	require.Equal(t, int64(60928), f1.PktDts())
-	require.NotNil(t, f1.UnsafePointer())
+	require.Equal(t, f1.c, f1.UnsafeTypedPointer())
 
-	f2 := astiav.AllocFrame()
+	f2 := AllocFrame()
 	require.NotNil(t, f2)
 	defer f2.Free()
-	f2.SetChannelLayout(astiav.ChannelLayout21)
-	f2.SetColorRange(astiav.ColorRangeJpeg)
+	f2.SetChannelLayout(ChannelLayout21)
+	f2.SetColorRange(ColorRangeJpeg)
 	f2.SetHeight(2)
 	f2.SetKeyFrame(true)
 	f2.SetNbSamples(4)
-	f2.SetPictureType(astiav.PictureTypeB)
-	f2.SetPixelFormat(astiav.PixelFormat0Bgr)
-	require.Equal(t, astiav.PixelFormat0Bgr, f2.PixelFormat()) // Need to test it right away as sample format actually updates the same field
+	f2.SetPictureType(PictureTypeB)
+	f2.SetPixelFormat(PixelFormat0Bgr)
+	require.Equal(t, PixelFormat0Bgr, f2.PixelFormat()) // Need to test it right away as sample format actually updates the same field
 	f2.SetPts(7)
-	f2.SetSampleAspectRatio(astiav.NewRational(10, 2))
-	f2.SetSampleFormat(astiav.SampleFormatDbl)
-	require.Equal(t, astiav.SampleFormatDbl, f2.SampleFormat())
+	f2.SetSampleAspectRatio(NewRational(10, 2))
+	f2.SetSampleFormat(SampleFormatDbl)
+	require.Equal(t, SampleFormatDbl, f2.SampleFormat())
 	f2.SetSampleRate(9)
 	f2.SetWidth(10)
-	require.True(t, f2.ChannelLayout().Equal(astiav.ChannelLayout21))
-	require.Equal(t, astiav.ColorRangeJpeg, f2.ColorRange())
+	require.True(t, f2.ChannelLayout().Equal(ChannelLayout21))
+	require.Equal(t, ColorRangeJpeg, f2.ColorRange())
 	require.Equal(t, 2, f2.Height())
 	require.True(t, f2.KeyFrame())
 	require.Equal(t, 4, f2.NbSamples())
-	require.Equal(t, astiav.PictureTypeB, f2.PictureType())
+	require.Equal(t, PictureTypeB, f2.PictureType())
 	require.Equal(t, int64(7), f2.Pts())
-	require.Equal(t, astiav.NewRational(10, 2), f2.SampleAspectRatio())
+	require.Equal(t, NewRational(10, 2), f2.SampleAspectRatio())
 	require.Equal(t, 9, f2.SampleRate())
 	require.Equal(t, 10, f2.Width())
 
@@ -61,40 +60,40 @@ func TestFrame(t *testing.T) {
 	f3.Unref()
 	require.Equal(t, 0, f3.Height())
 
-	f4 := astiav.AllocFrame()
+	f4 := AllocFrame()
 	require.NotNil(t, f4)
 	defer f4.Free()
 	f4.SetNbSamples(960)
-	f4.SetChannelLayout(astiav.ChannelLayoutStereo)
-	f4.SetSampleFormat(astiav.SampleFormatS16)
+	f4.SetChannelLayout(ChannelLayoutStereo)
+	f4.SetSampleFormat(SampleFormatS16)
 	f4.SetSampleRate(48000)
 	err = f4.AllocBuffer(0)
 	require.NoError(t, err)
 	err = f4.AllocSamples(0)
 	require.NoError(t, err)
 
-	f5 := astiav.AllocFrame()
+	f5 := AllocFrame()
 	require.NotNil(t, f5)
 	defer f5.Free()
-	sd := f5.NewSideData(astiav.FrameSideDataTypeAudioServiceType, 4)
+	sd := f5.NewSideData(FrameSideDataTypeAudioServiceType, 4)
 	require.NotNil(t, sd)
 	sd.SetData([]byte{1, 2, 3})
-	sd = f5.SideData(astiav.FrameSideDataTypeAudioServiceType)
+	sd = f5.SideData(FrameSideDataTypeAudioServiceType)
 	require.NotNil(t, sd)
-	require.Equal(t, astiav.FrameSideDataTypeAudioServiceType, sd.Type())
+	require.Equal(t, FrameSideDataTypeAudioServiceType, sd.Type())
 	require.True(t, bytes.HasPrefix(sd.Data(), []byte{1, 2, 3}))
 	require.Len(t, sd.Data(), 4)
 	sd.SetData([]byte{1, 2, 3, 4, 5})
-	sd = f5.SideData(astiav.FrameSideDataTypeAudioServiceType)
+	sd = f5.SideData(FrameSideDataTypeAudioServiceType)
 	require.NotNil(t, sd)
 	require.Equal(t, []byte{1, 2, 3, 4}, sd.Data())
 
-	f6 := astiav.AllocFrame()
+	f6 := AllocFrame()
 	require.NotNil(t, f6)
 	defer f6.Free()
-	f6.SetColorRange(astiav.ColorRangeUnspecified)
+	f6.SetColorRange(ColorRangeUnspecified)
 	f6.SetHeight(2)
-	f6.SetPixelFormat(astiav.PixelFormatYuv420P)
+	f6.SetPixelFormat(PixelFormatYuv420P)
 	f6.SetWidth(4)
 	const align = 1
 	require.NoError(t, f6.AllocBuffer(align))
diff --git a/hardware_device_type_test.go b/hardware_device_type_test.go
index 06db25b..47913b1 100644
--- a/hardware_device_type_test.go
+++ b/hardware_device_type_test.go
@@ -1,13 +1,12 @@
-package astiav_test
+package astiav
 
 import (
 	"testing"
 
-	"github.com/asticode/go-astiav"
 	"github.com/stretchr/testify/require"
 )
 
 func TestHardwareDeviceType(t *testing.T) {
-	require.Equal(t, "cuda", astiav.HardwareDeviceTypeCUDA.String())
-	require.Equal(t, astiav.FindHardwareDeviceTypeByName("cuda"), astiav.HardwareDeviceTypeCUDA)
+	require.Equal(t, "cuda", HardwareDeviceTypeCUDA.String())
+	require.Equal(t, FindHardwareDeviceTypeByName("cuda"), HardwareDeviceTypeCUDA)
 }
diff --git a/input_format_test.go b/input_format_test.go
index 4e1fdd4..42e94c2 100644
--- a/input_format_test.go
+++ b/input_format_test.go
@@ -1,15 +1,14 @@
-package astiav_test
+package astiav
 
 import (
 	"testing"
 
-	"github.com/asticode/go-astiav"
 	"github.com/stretchr/testify/require"
 )
 
 func TestInputFormat(t *testing.T) {
 	formatName := "rawvideo"
-	inputFormat := astiav.FindInputFormat(formatName)
+	inputFormat := FindInputFormat(formatName)
 	require.NotNil(t, inputFormat)
 	require.Equal(t, formatName, inputFormat.Name())
 	require.Equal(t, formatName, inputFormat.String())
diff --git a/int_read_write_test.go b/int_read_write_test.go
index 714cb18..f7c82d6 100644
--- a/int_read_write_test.go
+++ b/int_read_write_test.go
@@ -1,16 +1,15 @@
-package astiav_test
+package astiav
 
 import (
 	"testing"
 
-	"github.com/asticode/go-astiav"
 	"github.com/stretchr/testify/require"
 )
 
 func TestIntReadWrite(t *testing.T) {
 	is := []uint8{1, 2, 3, 4, 5, 6, 7, 8}
-	require.Equal(t, uint32(0), astiav.RL32([]byte{}))
-	require.Equal(t, uint32(0x4030201), astiav.RL32(is))
-	require.Equal(t, uint32(0), astiav.RL32WithOffset([]byte{}, 4))
-	require.Equal(t, uint32(0x8070605), astiav.RL32WithOffset(is, 4))
+	require.Equal(t, uint32(0), RL32([]byte{}))
+	require.Equal(t, uint32(0x4030201), RL32(is))
+	require.Equal(t, uint32(0), RL32WithOffset([]byte{}, 4))
+	require.Equal(t, uint32(0x8070605), RL32WithOffset(is, 4))
 }
diff --git a/internal/cmd/flags/main.go b/internal/cmd/flags/main.go
index c5f05bf..4e968a3 100644
--- a/internal/cmd/flags/main.go
+++ b/internal/cmd/flags/main.go
@@ -61,21 +61,20 @@ func (fs {{ $val.Name }}Flags{{ $val.Suffix }}) Has(f {{ $val.Name }}Flag{{ $val
 {{ end }}`
 
 var tmplTest = `// Code generated by astiav. DO NOT EDIT.
-package astiav_test
+package astiav
 import (
 	"testing"
 
-	"github.com/asticode/go-astiav"
 	"github.com/stretchr/testify/require"
 )
 {{ range $val := . }}
 func Test{{ $val.Name }}Flags{{ $val.Suffix }}(t *testing.T) {
-	fs := astiav.New{{ $val.Name }}Flags{{ $val.Suffix }}(astiav.{{ $val.Name }}Flag{{ $val.Suffix }}(1))
-	require.True(t, fs.Has(astiav.{{ $val.Name }}Flag{{ $val.Suffix }}(1)))
-	fs = fs.Add(astiav.{{ $val.Name }}Flag{{ $val.Suffix }}(2))
-	require.True(t, fs.Has(astiav.{{ $val.Name }}Flag{{ $val.Suffix }}(2)))
-	fs = fs.Del(astiav.{{ $val.Name }}Flag{{ $val.Suffix }}(2))
-	require.False(t, fs.Has(astiav.{{ $val.Name }}Flag{{ $val.Suffix }}(2)))
+	fs := New{{ $val.Name }}Flags{{ $val.Suffix }}({{ $val.Name }}Flag{{ $val.Suffix }}(1))
+	require.True(t, fs.Has({{ $val.Name }}Flag{{ $val.Suffix }}(1)))
+	fs = fs.Add({{ $val.Name }}Flag{{ $val.Suffix }}(2))
+	require.True(t, fs.Has({{ $val.Name }}Flag{{ $val.Suffix }}(2)))
+	fs = fs.Del({{ $val.Name }}Flag{{ $val.Suffix }}(2))
+	require.False(t, fs.Has({{ $val.Name }}Flag{{ $val.Suffix }}(2)))
 }
 {{ end }}`
 
diff --git a/io_context.go b/io_context.go
index d03eeb9..eef486a 100644
--- a/io_context.go
+++ b/io_context.go
@@ -10,25 +10,37 @@ type IOContext struct {
 	c *C.struct_AVIOContext
 }
 
-func NewIOContext() *IOContext {
-	return &IOContext{}
-}
-
 func newIOContextFromC(c *C.struct_AVIOContext) *IOContext {
 	if c == nil {
 		return nil
 	}
-	return &IOContext{c: c}
+	ic := &IOContext{c: c}
+	classers.set(ic)
+	return ic
+}
+
+var _ Classer = (*IOContext)(nil)
+
+func OpenIOContext(filename string, flags IOContextFlags) (*IOContext, error) {
+	cfi := C.CString(filename)
+	defer C.free(unsafe.Pointer(cfi))
+	var c *C.struct_AVIOContext
+	if err := newError(C.avio_open(&c, cfi, C.int(flags))); err != nil {
+		return nil, err
+	}
+	return newIOContextFromC(c), nil
+}
+
+func (ic *IOContext) Class() *Class {
+	return newClassFromC(unsafe.Pointer(ic.c))
 }
 
 func (ic *IOContext) Closep() error {
-	return newError(C.avio_closep(&ic.c))
-}
-
-func (ic *IOContext) Open(filename string, flags IOContextFlags) error {
-	cfi := C.CString(filename)
-	defer C.free(unsafe.Pointer(cfi))
-	return newError(C.avio_open(&ic.c, cfi, C.int(flags)))
+	classers.del(ic)
+	if ic.c != nil {
+		return newError(C.avio_closep(&ic.c))
+	}
+	return nil
 }
 
 func (ic *IOContext) Write(b []byte) {
diff --git a/io_context_test.go b/io_context_test.go
index 3ddf63a..fe4c7f0 100644
--- a/io_context_test.go
+++ b/io_context_test.go
@@ -1,19 +1,20 @@
-package astiav_test
+package astiav
 
 import (
 	"os"
 	"path/filepath"
 	"testing"
 
-	"github.com/asticode/go-astiav"
 	"github.com/stretchr/testify/require"
 )
 
 func TestIOContext(t *testing.T) {
-	c := astiav.NewIOContext()
 	path := filepath.Join(t.TempDir(), "iocontext.txt")
-	err := c.Open(path, astiav.NewIOContextFlags(astiav.IOContextFlagWrite))
+	c, err := OpenIOContext(path, NewIOContextFlags(IOContextFlagWrite))
 	require.NoError(t, err)
+	cl := c.Class()
+	require.NotNil(t, cl)
+	require.Equal(t, "AVIOContext", cl.Name())
 	c.Write(nil)
 	c.Write([]byte("test"))
 	err = c.Closep()
diff --git a/log.go b/log.go
index 481f7ed..9441788 100644
--- a/log.go
+++ b/log.go
@@ -5,19 +5,14 @@ package astiav
 //#include <stdio.h>
 //#include <stdlib.h>
 /*
-extern void goAstiavLogCallback(int level, char* fmt, char* msg, char* parent);
+extern void goAstiavLogCallback(void* ptr, int level, char* fmt, char* msg);
 
-static inline void astiavLogCallback(void *avcl, int level, const char *fmt, va_list vl)
+static inline void astiavLogCallback(void *ptr, int level, const char *fmt, va_list vl)
 {
 	if (level > av_log_get_level()) return;
-	AVClass* avc = avcl ? *(AVClass **) avcl : NULL;
-	char parent[1024];
-	if (avc) {
-		sprintf(parent, "%p", avcl);
-	}
 	char msg[1024];
 	vsprintf(msg, fmt, vl);
-	goAstiavLogCallback(level, (char*)(fmt), msg, parent);
+	goAstiavLogCallback(ptr, level, (char*)(fmt), msg);
 }
 static inline void astiavSetLogCallback()
 {
@@ -27,13 +22,15 @@ static inline void astiavResetLogCallback()
 {
 	av_log_set_callback(av_log_default_callback);
 }
-static inline void astiavLog(int level, const char *fmt)
+static inline void astiavLog(void* ptr, int level, const char *fmt, char* arg)
 {
-	av_log(NULL, level, fmt, NULL);
+	av_log(ptr, level, fmt, arg);
 }
 */
 import "C"
-import "unsafe"
+import (
+	"unsafe"
+)
 
 type LogLevel int
 
@@ -53,7 +50,11 @@ func SetLogLevel(l LogLevel) {
 	C.av_log_set_level(C.int(l))
 }
 
-type LogCallback func(l LogLevel, fmt, msg, parent string)
+func GetLogLevel() LogLevel {
+	return LogLevel(C.av_log_get_level())
+}
+
+type LogCallback func(c Classer, l LogLevel, fmt, msg string)
 
 var logCallback LogCallback
 
@@ -63,19 +64,42 @@ func SetLogCallback(c LogCallback) {
 }
 
 //export goAstiavLogCallback
-func goAstiavLogCallback(level C.int, fmt, msg, parent *C.char) {
+func goAstiavLogCallback(ptr unsafe.Pointer, level C.int, fmt, msg *C.char) {
+	// No callback
 	if logCallback == nil {
 		return
 	}
-	logCallback(LogLevel(level), C.GoString(fmt), C.GoString(msg), C.GoString(parent))
+
+	// Get classer
+	var c Classer
+	if ptr != nil {
+		var ok bool
+		if c, ok = classers.get(ptr); !ok {
+			c = newUnknownClasser(ptr)
+		}
+	}
+
+	// Callback
+	logCallback(c, LogLevel(level), C.GoString(fmt), C.GoString(msg))
 }
 
 func ResetLogCallback() {
 	C.astiavResetLogCallback()
 }
 
-func Log(l LogLevel, msg string) {
-	msgc := C.CString(msg)
-	defer C.free(unsafe.Pointer(msgc))
-	C.astiavLog(C.int(l), msgc)
+func Log(c Classer, l LogLevel, fmt string, args ...string) {
+	fmtc := C.CString(fmt)
+	defer C.free(unsafe.Pointer(fmtc))
+	argc := (*C.char)(nil)
+	if len(args) > 0 {
+		argc = C.CString(args[0])
+		defer C.free(unsafe.Pointer(argc))
+	}
+	var ptr unsafe.Pointer
+	if c != nil {
+		if cl := c.Class(); cl != nil {
+			ptr = cl.ptr
+		}
+	}
+	C.astiavLog(ptr, C.int(l), fmtc, argc)
 }
diff --git a/log_test.go b/log_test.go
index 6651246..37fd302 100644
--- a/log_test.go
+++ b/log_test.go
@@ -1,51 +1,73 @@
-package astiav_test
+package astiav
 
 import (
 	"testing"
 
-	"github.com/asticode/go-astiav"
 	"github.com/stretchr/testify/require"
 )
 
 type logItem struct {
+	c   Classer
 	fmt string
-	l   astiav.LogLevel
+	l   LogLevel
 	msg string
 }
 
 func TestLog(t *testing.T) {
 	var lis []logItem
-	astiav.SetLogCallback(func(l astiav.LogLevel, fmt, msg, parent string) {
+
+	SetLogLevel(LogLevelWarning)
+	require.Equal(t, LogLevelWarning, GetLogLevel())
+
+	SetLogCallback(func(c Classer, l LogLevel, fmt, msg string) {
 		lis = append(lis, logItem{
+			c:   c,
 			fmt: fmt,
 			l:   l,
 			msg: msg,
 		})
 	})
-	astiav.SetLogLevel(astiav.LogLevelWarning)
-	astiav.Log(astiav.LogLevelInfo, "info")
-	astiav.Log(astiav.LogLevelWarning, "warning")
-	astiav.Log(astiav.LogLevelError, "error")
-	astiav.Log(astiav.LogLevelFatal, "fatal")
+	f := AllocFilterGraph()
+	defer f.Free()
+	Log(f, LogLevelInfo, "info")
+	Log(f, LogLevelWarning, "warning %s", "arg")
+	Log(f, LogLevelError, "error")
+	Log(f, LogLevelFatal, "fatal")
 	require.Equal(t, []logItem{
 		{
-			fmt: "warning",
-			l:   astiav.LogLevelWarning,
-			msg: "warning",
+			c:   f,
+			fmt: "warning %s",
+			l:   LogLevelWarning,
+			msg: "warning arg",
 		},
 		{
+			c:   f,
 			fmt: "error",
-			l:   astiav.LogLevelError,
+			l:   LogLevelError,
 			msg: "error",
 		},
 		{
+			c:   f,
 			fmt: "fatal",
-			l:   astiav.LogLevelFatal,
+			l:   LogLevelFatal,
 			msg: "fatal",
 		},
 	}, lis)
-	astiav.ResetLogCallback()
+
+	ResetLogCallback()
 	lis = []logItem{}
-	astiav.Log(astiav.LogLevelError, "test error log\n")
+	Log(nil, LogLevelError, "test error log\n")
 	require.Equal(t, []logItem{}, lis)
+
+	lcs := []Classer{}
+	SetLogCallback(func(c Classer, l LogLevel, fmt, msg string) {
+		if c != nil {
+			lcs = append(lcs, c)
+		}
+	})
+	classers.del(f)
+	lcs = []Classer{}
+	Log(f, LogLevelWarning, "")
+	require.Len(t, lcs, 1)
+	require.IsType(t, &UnknownClasser{}, lcs[0])
 }
diff --git a/mathematics_test.go b/mathematics_test.go
index 2fe9834..5e909f8 100644
--- a/mathematics_test.go
+++ b/mathematics_test.go
@@ -1,14 +1,13 @@
-package astiav_test
+package astiav
 
 import (
 	"testing"
 
-	"github.com/asticode/go-astiav"
 	"github.com/stretchr/testify/require"
 )
 
 func TestMathematics(t *testing.T) {
-	require.Equal(t, int64(1000), astiav.RescaleQ(100, astiav.NewRational(1, 100), astiav.NewRational(1, 1000)))
-	require.Equal(t, int64(0), astiav.RescaleQRnd(1, astiav.NewRational(1, 100), astiav.NewRational(1, 10), astiav.RoundingDown))
-	require.Equal(t, int64(1), astiav.RescaleQRnd(1, astiav.NewRational(1, 100), astiav.NewRational(1, 10), astiav.RoundingUp))
+	require.Equal(t, int64(1000), RescaleQ(100, NewRational(1, 100), NewRational(1, 1000)))
+	require.Equal(t, int64(0), RescaleQRnd(1, NewRational(1, 100), NewRational(1, 10), RoundingDown))
+	require.Equal(t, int64(1), RescaleQRnd(1, NewRational(1, 100), NewRational(1, 10), RoundingUp))
 }
diff --git a/media_type_test.go b/media_type_test.go
index 5d478ff..190edee 100644
--- a/media_type_test.go
+++ b/media_type_test.go
@@ -1,12 +1,11 @@
-package astiav_test
+package astiav
 
 import (
 	"testing"
 
-	"github.com/asticode/go-astiav"
 	"github.com/stretchr/testify/require"
 )
 
 func TestMediaType(t *testing.T) {
-	require.Equal(t, "video", astiav.MediaTypeVideo.String())
+	require.Equal(t, "video", MediaTypeVideo.String())
 }
diff --git a/packet_test.go b/packet_test.go
index 3ed6657..9a335f4 100644
--- a/packet_test.go
+++ b/packet_test.go
@@ -1,9 +1,8 @@
-package astiav_test
+package astiav
 
 import (
 	"testing"
 
-	"github.com/asticode/go-astiav"
 	"github.com/stretchr/testify/require"
 )
 
@@ -13,13 +12,13 @@ func TestPacket(t *testing.T) {
 	require.Equal(t, []byte{0x0, 0x0, 0x0, 0xd1, 0x65, 0x88, 0x82, 0x0, 0x1f, 0x5f, 0xff, 0xf8, 0x22, 0x8a, 0x0, 0x2, 0x2d, 0xbe, 0x38, 0xc7, 0x19, 0x39, 0x39, 0x39, 0x39, 0x39, 0x39, 0x39, 0x39, 0x39, 0x39, 0x39, 0x39, 0x39, 0x39, 0x39, 0x39, 0x39, 0x39, 0x3a, 0xeb, 0xae, 0xba, 0xeb, 0xae, 0xba, 0xeb, 0xae, 0xba, 0xeb, 0xae, 0xba, 0xeb, 0xae, 0xba, 0xeb, 0xae, 0xba, 0xeb, 0xae, 0xba, 0xeb, 0xae, 0xba, 0xeb, 0xae, 0xba, 0xeb, 0xae, 0xba, 0xeb, 0xae, 0xba, 0xeb, 0xae, 0xba, 0xeb, 0xae, 0xba, 0xeb, 0xae, 0xba, 0xeb, 0xae, 0xba, 0xeb, 0xae, 0xba, 0xeb, 0xae, 0xba, 0xeb, 0xae, 0xba, 0xeb, 0xae, 0xba, 0xeb, 0xae, 0xba, 0xeb, 0xae, 0xba, 0xeb, 0xae, 0xba, 0xeb, 0xae, 0xba, 0xeb, 0xae, 0xba, 0xeb, 0xae, 0xba, 0xeb, 0xae, 0xba, 0xeb, 0xae, 0xba, 0xeb, 0xae, 0xba, 0xeb, 0xae, 0xba, 0xeb, 0xae, 0xba, 0xeb, 0xae, 0xba, 0xeb, 0xae, 0xba, 0xeb, 0xae, 0xba, 0xeb, 0xae, 0xba, 0xeb, 0xae, 0xba, 0xeb, 0xae, 0xba, 0xeb, 0xae, 0xba, 0xeb, 0xae, 0xba, 0xeb, 0xae, 0xba, 0xeb, 0xae, 0xba, 0xeb, 0xae, 0xba, 0xeb, 0xae, 0xba, 0xeb, 0xae, 0xba, 0xeb, 0xae, 0xba, 0xeb, 0xae, 0xba, 0xeb, 0xae, 0xba, 0xeb, 0xae, 0xba, 0xeb, 0xae, 0xba, 0xeb, 0xae, 0xba, 0xeb, 0xae, 0xb9, 0xb8, 0xe6, 0x39, 0xa5, 0xa5, 0xa5, 0xa5, 0xa5, 0xa5, 0xa5, 0xa5, 0xa5, 0xa5, 0xa5, 0xa5, 0xa5, 0xa5, 0xa5, 0xa5, 0xa5, 0xa5, 0xa5, 0xc0}, pkt1.Data())
 	require.Equal(t, int64(0), pkt1.Dts())
 	require.Equal(t, int64(512), pkt1.Duration())
-	require.True(t, pkt1.Flags().Has(astiav.PacketFlagKey))
+	require.True(t, pkt1.Flags().Has(PacketFlagKey))
 	require.Equal(t, int64(48), pkt1.Pos())
 	require.Equal(t, int64(0), pkt1.Pts())
 	require.Equal(t, 213, pkt1.Size())
 	require.Equal(t, 0, pkt1.StreamIndex())
 
-	pkt2 := astiav.AllocPacket()
+	pkt2 := AllocPacket()
 	require.NotNil(t, pkt2)
 	defer pkt2.Free()
 	require.Nil(t, pkt2.Data())
@@ -28,14 +27,14 @@ func TestPacket(t *testing.T) {
 	require.Len(t, pkt2.Data(), 5)
 	pkt2.SetDts(1)
 	pkt2.SetDuration(2)
-	pkt2.SetFlags(astiav.NewPacketFlags(3))
+	pkt2.SetFlags(NewPacketFlags(3))
 	pkt2.SetPos(4)
 	pkt2.SetPts(5)
 	pkt2.SetSize(6)
 	pkt2.SetStreamIndex(7)
 	require.Equal(t, int64(1), pkt2.Dts())
 	require.Equal(t, int64(2), pkt2.Duration())
-	require.Equal(t, astiav.NewPacketFlags(3), pkt2.Flags())
+	require.Equal(t, NewPacketFlags(3), pkt2.Flags())
 	require.Equal(t, int64(4), pkt2.Pos())
 	require.Equal(t, int64(5), pkt2.Pts())
 	require.Equal(t, 6, pkt2.Size())
@@ -60,26 +59,26 @@ func TestPacket(t *testing.T) {
 	pkt3.SetDts(10)
 	pkt3.SetDuration(20)
 	pkt3.SetPts(30)
-	pkt3.RescaleTs(astiav.NewRational(1, 10), astiav.NewRational(1, 1))
+	pkt3.RescaleTs(NewRational(1, 10), NewRational(1, 1))
 	require.Equal(t, int64(1), pkt3.Dts())
 	require.Equal(t, int64(2), pkt3.Duration())
 	require.Equal(t, int64(3), pkt3.Pts())
 
-	pkt4 := astiav.AllocPacket()
+	pkt4 := AllocPacket()
 	require.NotNil(t, pkt4)
 	defer pkt4.Free()
 	b := []byte("test")
 	require.NoError(t, pkt4.FromData(b))
 	require.Equal(t, b, pkt4.Data())
 
-	pkt5 := astiav.AllocPacket()
+	pkt5 := AllocPacket()
 	require.NotNil(t, pkt5)
 	defer pkt5.Free()
 	b = []byte{1, 2, 3, 4}
-	require.NoError(t, pkt5.AddSideData(astiav.PacketSideDataTypeAudioServiceType, b))
-	require.Equal(t, b, pkt5.SideData(astiav.PacketSideDataTypeAudioServiceType))
+	require.NoError(t, pkt5.AddSideData(PacketSideDataTypeAudioServiceType, b))
+	require.Equal(t, b, pkt5.SideData(PacketSideDataTypeAudioServiceType))
 
-	pkt6 := astiav.AllocPacket()
+	pkt6 := AllocPacket()
 	require.NotNil(t, pkt6)
 	defer pkt6.Free()
 	b = []byte{}
diff --git a/picture_type_test.go b/picture_type_test.go
index e0f0e69..d92cdcd 100644
--- a/picture_type_test.go
+++ b/picture_type_test.go
@@ -1,12 +1,11 @@
-package astiav_test
+package astiav
 
 import (
 	"testing"
 
-	"github.com/asticode/go-astiav"
 	"github.com/stretchr/testify/require"
 )
 
 func TestPictureType(t *testing.T) {
-	require.Equal(t, "I", astiav.PictureTypeI.String())
+	require.Equal(t, "I", PictureTypeI.String())
 }
diff --git a/pixel_format_test.go b/pixel_format_test.go
index 0c2a6eb..9ce4c2a 100644
--- a/pixel_format_test.go
+++ b/pixel_format_test.go
@@ -1,14 +1,13 @@
-package astiav_test
+package astiav
 
 import (
 	"testing"
 
-	"github.com/asticode/go-astiav"
 	"github.com/stretchr/testify/require"
 )
 
 func TestPixelFormat(t *testing.T) {
-	p := astiav.FindPixelFormatByName("yuv420p")
-	require.Equal(t, astiav.PixelFormatYuv420P, p)
+	p := FindPixelFormatByName("yuv420p")
+	require.Equal(t, PixelFormatYuv420P, p)
 	require.Equal(t, "yuv420p", p.String())
 }
diff --git a/rational_test.go b/rational_test.go
index 79fc2b5..c34eb14 100644
--- a/rational_test.go
+++ b/rational_test.go
@@ -1,14 +1,13 @@
-package astiav_test
+package astiav
 
 import (
 	"testing"
 
-	"github.com/asticode/go-astiav"
 	"github.com/stretchr/testify/require"
 )
 
 func TestRational(t *testing.T) {
-	r := astiav.NewRational(2, 1)
+	r := NewRational(2, 1)
 	require.Equal(t, 2, r.Num())
 	require.Equal(t, 1, r.Den())
 	r.SetNum(1)
diff --git a/sample_format_test.go b/sample_format_test.go
index fe6a426..ffaea35 100644
--- a/sample_format_test.go
+++ b/sample_format_test.go
@@ -1,12 +1,11 @@
-package astiav_test
+package astiav
 
 import (
 	"testing"
 
-	"github.com/asticode/go-astiav"
 	"github.com/stretchr/testify/require"
 )
 
 func TestSampleFormat(t *testing.T) {
-	require.Equal(t, "s16", astiav.SampleFormatS16.String())
+	require.Equal(t, "s16", SampleFormatS16.String())
 }
diff --git a/software_scale_context.go b/software_scale_context.go
index c1df881..a40cffb 100644
--- a/software_scale_context.go
+++ b/software_scale_context.go
@@ -5,6 +5,7 @@ package astiav
 import "C"
 import (
 	"errors"
+	"unsafe"
 )
 
 // https://github.com/FFmpeg/FFmpeg/blob/n5.0/libswscale/swscale_internal.h#L300
@@ -31,7 +32,7 @@ type softwareScaleContextUpdate struct {
 }
 
 func CreateSoftwareScaleContext(srcW, srcH int, srcFormat PixelFormat, dstW, dstH int, dstFormat PixelFormat, flags SoftwareScaleContextFlags) (*SoftwareScaleContext, error) {
-	ssc := SoftwareScaleContext{
+	ssc := &SoftwareScaleContext{
 		dstFormat: C.enum_AVPixelFormat(dstFormat),
 		dstH:      C.int(dstH),
 		dstW:      C.int(dstW),
@@ -54,7 +55,20 @@ func CreateSoftwareScaleContext(srcW, srcH int, srcFormat PixelFormat, dstW, dst
 	if ssc.c == nil {
 		return nil, errors.New("astiav: empty new context")
 	}
-	return &ssc, nil
+
+	classers.set(ssc)
+	return ssc, nil
+}
+
+func (ssc *SoftwareScaleContext) Free() {
+	classers.del(ssc)
+	C.sws_freeContext(ssc.c)
+}
+
+var _ Classer = (*SoftwareScaleContext)(nil)
+
+func (ssc *SoftwareScaleContext) Class() *Class {
+	return newClassFromC(unsafe.Pointer(ssc.c))
 }
 
 func (ssc *SoftwareScaleContext) ScaleFrame(src, dst *Frame) error {
@@ -195,9 +209,3 @@ func (ssc *SoftwareScaleContext) SourceResolution() (int, int) {
 func (ssc *SoftwareScaleContext) SetSourceResolution(w int, h int) error {
 	return ssc.update(softwareScaleContextUpdate{srcW: &w, srcH: &h})
 }
-
-func (ssc *SoftwareScaleContext) Free() {
-	if ssc.c != nil {
-		C.sws_freeContext(ssc.c)
-	}
-}
diff --git a/software_scale_context_test.go b/software_scale_context_test.go
index e5cf7fa..99b524e 100644
--- a/software_scale_context_test.go
+++ b/software_scale_context_test.go
@@ -1,40 +1,39 @@
-package astiav_test
+package astiav
 
 import (
 	"os"
 	"testing"
 
-	"github.com/asticode/go-astiav"
 	"github.com/stretchr/testify/require"
 )
 
 func TestSoftwareScaleContext(t *testing.T) {
-	f1 := astiav.AllocFrame()
+	f1 := AllocFrame()
 	require.NotNil(t, f1)
 	defer f1.Free()
 
-	f2 := astiav.AllocFrame()
+	f2 := AllocFrame()
 	require.NotNil(t, f2)
 	defer f2.Free()
 
-	f3 := astiav.AllocFrame()
+	f3 := AllocFrame()
 	require.NotNil(t, f3)
 	defer f3.Free()
 
 	srcW := 4
 	srcH := 2
-	srcPixelFormat := astiav.PixelFormatYuv420P
+	srcPixelFormat := PixelFormatYuv420P
 	dstW := 8
 	dstH := 4
-	dstPixelFormat := astiav.PixelFormatRgba
-	swscf1 := astiav.SoftwareScaleContextFlags(astiav.SoftwareScaleContextFlagBilinear)
+	dstPixelFormat := PixelFormatRgba
+	swscf1 := SoftwareScaleContextFlags(SoftwareScaleContextFlagBilinear)
 
 	f1.SetHeight(srcH)
 	f1.SetWidth(srcW)
 	f1.SetPixelFormat(srcPixelFormat)
 	require.NoError(t, f1.AllocBuffer(1))
 
-	swsc1, err := astiav.CreateSoftwareScaleContext(srcW, srcH, srcPixelFormat, dstW, dstH, dstPixelFormat, swscf1)
+	swsc1, err := CreateSoftwareScaleContext(srcW, srcH, srcPixelFormat, dstW, dstH, dstPixelFormat, swscf1)
 	require.NoError(t, err)
 	defer swsc1.Free()
 	require.Equal(t, dstH, swsc1.DestinationHeight())
@@ -50,6 +49,9 @@ func TestSoftwareScaleContext(t *testing.T) {
 	require.Equal(t, w, srcW)
 	require.Equal(t, h, srcH)
 	require.Equal(t, srcW, swsc1.SourceWidth())
+	cl := swsc1.Class()
+	require.NotNil(t, cl)
+	require.Equal(t, "SWScaler", cl.Name())
 
 	require.NoError(t, swsc1.ScaleFrame(f1, f2))
 	require.Equal(t, dstH, f2.Height())
@@ -58,11 +60,11 @@ func TestSoftwareScaleContext(t *testing.T) {
 
 	dstW = 4
 	dstH = 3
-	dstPixelFormat = astiav.PixelFormatYuv420P
-	swscf2 := astiav.SoftwareScaleContextFlags(astiav.SoftwareScaleContextFlagPoint)
+	dstPixelFormat = PixelFormatYuv420P
+	swscf2 := SoftwareScaleContextFlags(SoftwareScaleContextFlagPoint)
 	srcW = 2
 	srcH = 1
-	srcPixelFormat = astiav.PixelFormatRgba
+	srcPixelFormat = PixelFormatRgba
 
 	require.NoError(t, swsc1.SetDestinationHeight(dstH))
 	require.Equal(t, dstH, swsc1.DestinationHeight())
@@ -91,14 +93,14 @@ func TestSoftwareScaleContext(t *testing.T) {
 	require.Equal(t, w, srcW)
 	require.Equal(t, h, srcH)
 
-	f4, err := globalHelper.inputLastFrame("image-rgba.png", astiav.MediaTypeVideo)
+	f4, err := globalHelper.inputLastFrame("image-rgba.png", MediaTypeVideo)
 	require.NoError(t, err)
 
-	f5 := astiav.AllocFrame()
+	f5 := AllocFrame()
 	require.NotNil(t, f5)
 	defer f5.Free()
 
-	swsc2, err := astiav.CreateSoftwareScaleContext(f4.Width(), f4.Height(), f4.PixelFormat(), 512, 512, f4.PixelFormat(), astiav.NewSoftwareScaleContextFlags(astiav.SoftwareScaleContextFlagBilinear))
+	swsc2, err := CreateSoftwareScaleContext(f4.Width(), f4.Height(), f4.PixelFormat(), 512, 512, f4.PixelFormat(), NewSoftwareScaleContextFlags(SoftwareScaleContextFlagBilinear))
 	require.NoError(t, err)
 	require.NoError(t, swsc2.ScaleFrame(f4, f5))
 
diff --git a/stream_test.go b/stream_test.go
index 78d5750..12db4d3 100644
--- a/stream_test.go
+++ b/stream_test.go
@@ -1,9 +1,8 @@
-package astiav_test
+package astiav
 
 import (
 	"testing"
 
-	"github.com/asticode/go-astiav"
 	"github.com/stretchr/testify/require"
 )
 
@@ -16,25 +15,25 @@ func TestStream(t *testing.T) {
 	s2 := ss[1]
 
 	require.Equal(t, 0, s1.Index())
-	require.Equal(t, astiav.NewRational(24, 1), s1.AvgFrameRate())
+	require.Equal(t, NewRational(24, 1), s1.AvgFrameRate())
 	require.Equal(t, int64(61440), s1.Duration())
-	require.True(t, s1.EventFlags().Has(astiav.StreamEventFlag(2)))
+	require.True(t, s1.EventFlags().Has(StreamEventFlag(2)))
 	require.Equal(t, 1, s1.ID())
-	require.Equal(t, "und", s1.Metadata().Get("language", nil, astiav.NewDictionaryFlags()).Value())
+	require.Equal(t, "und", s1.Metadata().Get("language", nil, NewDictionaryFlags()).Value())
 	require.Equal(t, int64(120), s1.NbFrames())
-	require.Equal(t, astiav.NewRational(24, 1), s1.RFrameRate())
-	require.Equal(t, astiav.NewRational(1, 1), s1.SampleAspectRatio())
-	require.Equal(t, []byte{}, s1.SideData(astiav.PacketSideDataTypeNb))
+	require.Equal(t, NewRational(24, 1), s1.RFrameRate())
+	require.Equal(t, NewRational(1, 1), s1.SampleAspectRatio())
+	require.Equal(t, []byte{}, s1.SideData(PacketSideDataTypeNb))
 	require.Equal(t, int64(0), s1.StartTime())
-	require.Equal(t, astiav.NewRational(1, 12288), s1.TimeBase())
+	require.Equal(t, NewRational(1, 12288), s1.TimeBase())
 
 	require.Equal(t, 1, s2.Index())
 	require.Equal(t, int64(240640), s2.Duration())
 	require.Equal(t, 2, s2.ID())
 	require.Equal(t, int64(235), s2.NbFrames())
 	require.Equal(t, int64(0), s2.StartTime())
-	require.Equal(t, astiav.NewRational(1, 48000), s2.TimeBase())
+	require.Equal(t, NewRational(1, 48000), s2.TimeBase())
 
-	s1.SetTimeBase(astiav.NewRational(1, 1))
-	require.Equal(t, astiav.NewRational(1, 1), s1.TimeBase())
+	s1.SetTimeBase(NewRational(1, 1))
+	require.Equal(t, NewRational(1, 1), s1.TimeBase())
 }
diff --git a/time_test.go b/time_test.go
index f31b4e9..912c3f4 100644
--- a/time_test.go
+++ b/time_test.go
@@ -1,12 +1,11 @@
-package astiav_test
+package astiav
 
 import (
 	"testing"
 
-	"github.com/asticode/go-astiav"
 	"github.com/stretchr/testify/require"
 )
 
 func TestTime(t *testing.T) {
-	require.NotEqual(t, 0, astiav.RelativeTime())
+	require.NotEqual(t, 0, RelativeTime())
 }