optimize code

add doc

decoder.go

@@ -59,16 +59,13 @@ func freeDecoder(decoder *decoder) {
 	}
 }
 
-func (decoder *decoder) Decode(packet *C.AVPacket) (pkt *Packet, err error) {
-	pkt = &Packet{}
+func (decoder *decoder) decode(packet *C.AVPacket) (pkt *Packet, err error) {
+	pkt = &Packet{
+		streamIndex: int(packet.stream_index),
+		codecType:   decoder.codecType,
+	}
 
-	pkt.streamIndex = int(packet.stream_index)
-	pkt.codecType = decoder.codecType
-
-	switch decoder.codecType {
-	case int(C.AVMEDIA_TYPE_AUDIO):
-	case int(C.AVMEDIA_TYPE_VIDEO):
-	default:
+	if !pkt.IsAudio() && !pkt.IsVideo() {
 		// do nothing
 		return
 	}
@@ -91,15 +88,15 @@ func (decoder *decoder) Decode(packet *C.AVPacket) (pkt *Packet, err error) {
 	pkt.duration = int64(frame.pkt_duration)
 	pkt.position = int64(frame.pkt_pos)
 
-	switch decoder.codecType {
-	case C.AVMEDIA_TYPE_VIDEO:
+	var encPacket C.AVPacket
+	defer C.av_packet_unref(&encPacket)
+
+	switch {
+	case pkt.IsVideo():
 		pkt.width = int(frame.width)
 		pkt.height = int(frame.height)
 		pkt.keyFrame = int(frame.key_frame) == 1
 
-		var encPacket C.AVPacket
-		defer C.av_packet_unref(&encPacket)
-
 		switch frame.format {
 		case C.AV_PIX_FMT_NONE, C.AV_PIX_FMT_YUVJ420P:
 			if cerr = C.rtsp_avcodec_encode_jpeg(decoder.codecCtx, frame, &encPacket); cerr != C.int(0) {
@@ -114,9 +111,7 @@ func (decoder *decoder) Decode(packet *C.AVPacket) (pkt *Packet, err error) {
 			}
 		}
 
-		pkt.data = decodeAVPacket(&encPacket)
-
-	case C.AVMEDIA_TYPE_AUDIO:
+	case pkt.IsAudio():
 		pkt.bitRate = int(decoder.codecCtx.bit_rate)
 		pkt.sampleRate = int(frame.sample_rate)
 		pkt.channels = int(frame.channels)
@@ -133,32 +128,23 @@ func (decoder *decoder) Decode(packet *C.AVPacket) (pkt *Packet, err error) {
 				}
 			}
 
-			var encPacket C.AVPacket
-			defer C.av_packet_unref(&encPacket)
-
 			if cerr = C.rtsp_avcodec_encode_resample_wav(decoder.codecCtx, decoder.swrContext, frame, &encPacket); cerr < C.int(0) {
 				err = fmt.Errorf("ffmpeg: rtsp_avcodec_encode_resample_wav failed: %s", CErr2Str(cerr))
 				return
 			}
-			pkt.data = decodeAVPacket(&encPacket)
 
 		case C.AV_SAMPLE_FMT_S16:
-			var encPacket C.AVPacket
-			defer C.av_packet_unref(&encPacket)
-
 			if cerr = C.rtsp_avcodec_encode_wav(decoder.codecCtx, frame, &encPacket); cerr != C.int(0) {
 				err = fmt.Errorf("ffmpeg: rtsp_avcodec_encode_wav failed: %s", CErr2Str(cerr))
 				return
 			}
-			pkt.data = decodeAVPacket(&encPacket)
 
 		default:
 			err = fmt.Errorf("ffmpeg: audio format %d not supported", frame.format)
 			return
 		}
-
-	default:
 	}
 
+	pkt.data = decodeAVPacket(&encPacket)
 	return
 }

pkt.go

@@ -3,6 +3,7 @@ package rtsp
 // #include "ffmpeg.h"
 import "C"
 
+// Image image meta
 type Image struct {
 	// only image
 	width    int
@@ -20,6 +21,7 @@ func (image *Image) Width() int {
 	return image.width
 }
 
+// Audio audio meta
 type Audio struct {
 	// only audio
 	sampleRate int
@@ -42,6 +44,7 @@ func (audio *Audio) Channels() int {
 	return audio.channels
 }
 
+// Packet decoded media packet
 type Packet struct {
 	streamIndex int
 	codecType   int
@@ -59,12 +62,17 @@ func (packet *Packet) Data() []byte {
 	return packet.data
 }
 
-// IsAudio packet
+// IsAudio is audio packet type
 func (packet *Packet) IsAudio() bool {
 	return packet.codecType == C.AVMEDIA_TYPE_AUDIO
 }
 
-// IsVideo packet
+// IsVideo is video packet type
 func (packet *Packet) IsVideo() bool {
 	return packet.codecType == C.AVMEDIA_TYPE_VIDEO
 }
+
+// Type packet type
+func (packet *Packet) Type() int {
+	return packet.codecType
+}

stream.go

@@ -13,14 +13,19 @@ import (
 	"unsafe"
 )
 
+// Type rtsp transport protocol
 type Type int
 
 const (
+	// Auto auto change
 	Auto Type = iota
+	// Tcp use tcp transport protocol
 	Tcp
+	// Udp use udp transport  protocol
 	Udp
 )
 
+// Stream media stream
 type Stream struct {
 	formatCtx  *C.AVFormatContext
 	dictionary *C.AVDictionary
@@ -30,7 +35,7 @@ type Stream struct {
 	uri      string
 }
 
-// New stream
+// New media stream
 func New(uri string) (stream *Stream) {
 	stream = &Stream{uri: uri}
 	stream.decoders = make(map[int]*decoder)
@@ -55,15 +60,17 @@ func free(stream *Stream) {
 	}
 }
 
+// ErrTimeout ETIMEDOUT
 type ErrTimeout struct {
 	err error
 }
 
+// Error error interface
 func (e ErrTimeout) Error() string {
 	return e.err.Error()
 }
 
-// Setup transport (tcp or udp)
+// Setup transport protocol (tcp, udp or auto)
 func (stream *Stream) Setup(t Type) (err error) {
 	transport := C.CString("rtsp_transport")
 	defer C.free(unsafe.Pointer(transport))
@@ -134,6 +141,7 @@ func (stream *Stream) Setup(t Type) (err error) {
 	return
 }
 
+// ReadPacket read frame from stream and decode it to Packet
 func (stream *Stream) ReadPacket() (pkt *Packet, err error) {
 	packet := C.av_packet_alloc()
 	defer C.av_packet_free(&packet)
@@ -153,7 +161,7 @@ func (stream *Stream) ReadPacket() (pkt *Packet, err error) {
 	defer stream.mu.RUnlock()
 
 	if decoder, ok := stream.decoders[int(packet.stream_index)]; ok {
-		return decoder.Decode(packet)
+		return decoder.decode(packet)
 	}
 
 	err = fmt.Errorf("ffmpeg: decoder not found %d", int(packet.stream_index))

types_darwin.go

@@ -10,6 +10,7 @@ import (
 	"unsafe"
 )
 
+// CErr2Str convert C error code to Go string
 func CErr2Str(code C.int) string {
 	buf := make([]byte, 64)
 

types_linux.go

@@ -10,6 +10,7 @@ import (
 	"unsafe"
 )
 
+// CErr2Str convert C error code to Go string
 func CErr2Str(code C.int) string {
 	buf := make([]byte, 64)
 

types_windows.go

@@ -10,6 +10,7 @@ import (
 	"unsafe"
 )
 
+// CErr2Str convert C error code to Go string
 func CErr2Str(code C.int) string {
 	buf := make([]byte, 64)