Add AVPixFmtDescriptor to retrieve flags for AVPixelFormat (#154)

* 1. Adds hardware_frames_constraints to retrieve valid HWPixelFormats and SWPixelFormats for specific hardware frame configurations.

2. Implements a HardwareFramesConstraints method in hardware_device_context to obtain these constraints for a given hardware frames context.

* Add AVPixFmtDescriptor to retrieve flags for AVPixelFormat

feat(PixelFormat): Expose `AVPixFmtDescriptor` via `Descriptor()` method

This commit introduces support for `AVPixFmtDescriptor`, which provides
detailed information about an `AVPixelFormat`, including its flags.

A new `Descriptor()` method has been added to the `PixelFormat` type
(or class) to retrieve its corresponding `AVPixFmtDescriptor`. This allows
for easier access to extended properties of pixel formats.

flags.go

@@ -305,6 +305,26 @@ func (fs PacketFlags) Del(f PacketFlag) PacketFlags {
 
 func (fs PacketFlags) Has(f PacketFlag) bool { return astikit.BitFlags(fs).Has(uint64(f)) }
 
+type PixelFormatDescriptorFlags astikit.BitFlags
+
+func NewPixelFormatDescriptorFlags(fs ...PixelFormatDescriptorFlag) PixelFormatDescriptorFlags {
+	o := PixelFormatDescriptorFlags(0)
+	for _, f := range fs {
+		o = o.Add(f)
+	}
+	return o
+}
+
+func (fs PixelFormatDescriptorFlags) Add(f PixelFormatDescriptorFlag) PixelFormatDescriptorFlags {
+	return PixelFormatDescriptorFlags(astikit.BitFlags(fs).Add(uint64(f)))
+}
+
+func (fs PixelFormatDescriptorFlags) Del(f PixelFormatDescriptorFlag) PixelFormatDescriptorFlags {
+	return PixelFormatDescriptorFlags(astikit.BitFlags(fs).Del(uint64(f)))
+}
+
+func (fs PixelFormatDescriptorFlags) Has(f PixelFormatDescriptorFlag) bool { return astikit.BitFlags(fs).Has(uint64(f)) }
+
 type SeekFlags astikit.BitFlags
 
 func NewSeekFlags(fs ...SeekFlag) SeekFlags {

flags_test.go

@@ -141,6 +141,15 @@ func TestPacketFlags(t *testing.T) {
 	require.False(t, fs.Has(PacketFlag(2)))
 }
 
+func TestPixelFormatDescriptorFlags(t *testing.T) {
+	fs := NewPixelFormatDescriptorFlags(PixelFormatDescriptorFlag(1))
+	require.True(t, fs.Has(PixelFormatDescriptorFlag(1)))
+	fs = fs.Add(PixelFormatDescriptorFlag(2))
+	require.True(t, fs.Has(PixelFormatDescriptorFlag(2)))
+	fs = fs.Del(PixelFormatDescriptorFlag(2))
+	require.False(t, fs.Has(PixelFormatDescriptorFlag(2)))
+}
+
 func TestSeekFlags(t *testing.T) {
 	fs := NewSeekFlags(SeekFlag(1))
 	require.True(t, fs.Has(SeekFlag(1)))

internal/cmd/flags/main.go

@@ -29,6 +29,7 @@ var list = []listItem{
 	{Name: "IOFormat"},
 	{Name: "OptionSearch"},
 	{Name: "Packet"},
+	{Name: "PixelFormatDescriptor"},
 	{Name: "Seek"},
 	{Name: "SoftwareScaleContext"},
 	{Name: "StreamEvent"},

pixel_format.go

@@ -211,6 +211,10 @@ func (f PixelFormat) String() string {
 	return f.Name()
 }
 
+func (f PixelFormat) Descriptor() *PixelFormatDescriptor {
+	return newPixelFormatDescriptorFromC(C.av_pix_fmt_desc_get((C.enum_AVPixelFormat)(f)))
+}
+
 // https://ffmpeg.org/doxygen/7.0/pixdesc_8c.html#a925ef18d69c24c3be8c53d5a7dc0660e
 func FindPixelFormatByName(name string) PixelFormat {
 	cn := C.CString(name)

pixel_format_descriptor.go

@@ -0,0 +1,26 @@
+package astiav
+
+//#include <libavutil/pixdesc.h>
+import "C"
+
+// https://ffmpeg.org/doxygen/7.0/structAVPixFmtDescriptor.html
+type PixelFormatDescriptor struct {
+	c *C.AVPixFmtDescriptor
+}
+
+func newPixelFormatDescriptorFromC(c *C.AVPixFmtDescriptor) *PixelFormatDescriptor {
+	if c == nil {
+		return nil
+	}
+	return &PixelFormatDescriptor{c: c}
+}
+
+// https://ffmpeg.org/doxygen/7.0/structAVPixFmtDescriptor.html#a10736c3f1288eb87b23ede3ffdefb435
+func (pfd *PixelFormatDescriptor) Name() string {
+	return C.GoString(pfd.c.name)
+}
+
+// https://ffmpeg.org/doxygen/7.0/structAVPixFmtDescriptor.html#a5047d1e6b045f637345dbc305bf4357d
+func (pfd *PixelFormatDescriptor) Flags() PixelFormatDescriptorFlags {
+	return PixelFormatDescriptorFlags(pfd.c.flags)
+}

pixel_format_descriptor_flag.go

@@ -0,0 +1,20 @@
+package astiav
+
+//#include <libavutil/pixdesc.h>
+import "C"
+
+// https://ffmpeg.org/doxygen/7.0/pixdesc_8h.html#ac7c7d0be16fb9b6f05b3e0d463cd037b
+type PixelFormatDescriptorFlag int64
+
+const (
+	PixelFormatDescriptorFlagBe        = PixelFormatDescriptorFlag(C.AV_PIX_FMT_FLAG_BE)
+	PixelFormatDescriptorFlagPal       = PixelFormatDescriptorFlag(C.AV_PIX_FMT_FLAG_PAL)
+	PixelFormatDescriptorFlagBitStream = PixelFormatDescriptorFlag(C.AV_PIX_FMT_FLAG_BITSTREAM)
+	PixelFormatDescriptorFlagHwAccel   = PixelFormatDescriptorFlag(C.AV_PIX_FMT_FLAG_HWACCEL)
+	PixelFormatDescriptorFlagPlanar    = PixelFormatDescriptorFlag(C.AV_PIX_FMT_FLAG_PLANAR)
+	PixelFormatDescriptorFlagRgb       = PixelFormatDescriptorFlag(C.AV_PIX_FMT_FLAG_RGB)
+	PixelFormatDescriptorFlagAlpha     = PixelFormatDescriptorFlag(C.AV_PIX_FMT_FLAG_ALPHA)
+	PixelFormatDescriptorFlagBayer     = PixelFormatDescriptorFlag(C.AV_PIX_FMT_FLAG_BAYER)
+	PixelFormatDescriptorFlagFloat     = PixelFormatDescriptorFlag(C.AV_PIX_FMT_FLAG_FLOAT)
+	PixelFormatDescriptorFlagXyz       = PixelFormatDescriptorFlag(C.AV_PIX_FMT_FLAG_XYZ)
+)

pixel_format_descriptor_test.go

@@ -0,0 +1,15 @@
+package astiav
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestPixelFormatDescriptor(t *testing.T) {
+	p := PixelFormatCuda
+	d := p.Descriptor()
+	require.NotNil(t, d)
+	require.Equal(t, d.Name(), p.String())
+	require.True(t, d.Flags().Has(PixelFormatDescriptorFlagHwAccel))
+}

pixel_format_test.go

@@ -10,4 +10,7 @@ func TestPixelFormat(t *testing.T) {
 	p := FindPixelFormatByName("yuv420p")
 	require.Equal(t, PixelFormatYuv420P, p)
 	require.Equal(t, "yuv420p", p.String())
+	d := p.Descriptor()
+	require.NotNil(t, d)
+	require.Equal(t, d.Name(), p.String())
 }