Fix AnnexB parsing in some cases

pkg/bubble/client.go

@@ -231,7 +231,7 @@ func (c *Client) Handle() error {
 				Header: rtp.Header{
 					Timestamp: core.Now90000(),
 				},
-				Payload: annexb.EncodeToAVCC(b[6:], false),
+				Payload: annexb.EncodeToAVCC(b[6:]),
 			}
 			c.videoTrack.WriteRTP(pkt)
 		} else {

pkg/dvrip/producer.go

@@ -53,7 +53,7 @@ func (c *Producer) Start() error {
 
 			packet := &rtp.Packet{
 				Header:  rtp.Header{Timestamp: c.videoTS},
-				Payload: annexb.EncodeToAVCC(payload, false),
+				Payload: annexb.EncodeToAVCC(payload),
 			}
 
 			//log.Printf("[AVC] %v, len: %d, ts: %10d", h265.Types(payload), len(payload), packet.Timestamp)
@@ -146,7 +146,7 @@ func (c *Producer) probe() error {
 			c.videoTS = binary.LittleEndian.Uint32(ts)
 			c.videoDT = 90000 / uint32(fps)
 
-			payload := annexb.EncodeToAVCC(b[16:], false)
+			payload := annexb.EncodeToAVCC(b[16:])
 			c.addVideoTrack(b[4], payload)
 
 		case 0xFA: // audio

pkg/h264/annexb/annexb.go

@@ -11,64 +11,60 @@ const startAUD = StartCode + "\x09\xF0"
 const startAUDstart = startAUD + StartCode
 
 // EncodeToAVCC
-// will change original slice data!
-// safeAppend should be used if original slice has useful data after end (part of other slice)
 //
 // FFmpeg MPEG-TS: 00000001 AUD 00000001 SPS 00000001 PPS 000001 IFrame
 // FFmpeg H264:    00000001 SPS 00000001 PPS 000001 IFrame 00000001 PFrame
-func EncodeToAVCC(b []byte, safeAppend bool) []byte {
-	const minSize = len(StartCode) + 1
-
-	// 1. Check frist "start code"
-	if len(b) < len(startAUDstart) || string(b[:len(StartCode)]) != StartCode {
-		return nil
-	}
-
-	// 2. Skip Access unit delimiter (AUD) from FFmpeg
-	if string(b[:len(startAUDstart)]) == startAUDstart {
-		b = b[6:]
-	}
-
+// Reolink:        000001 AUD 000001 VPS 00000001 SPS 00000001 PPS 00000001 IDR 00000001 IDR
+func EncodeToAVCC(annexb []byte) (avc []byte) {
 	var start int
 
-	for i, n := minSize, len(b)-minSize; i < n; {
-		// 3. Check "start code" (first 2 bytes)
-		if b[i] != 0 || b[i+1] != 0 {
-			i++
+	avc = make([]byte, 0, len(annexb)+4) // init memory with little overhead
+
+	for i := 0; ; i++ {
+		var offset int
+
+		if i+3 < len(annexb) {
+			// search next separator
+			if annexb[i] == 0 && annexb[i+1] == 0 {
+				if annexb[i+2] == 1 {
+					offset = 3 // 00 00 01
+				} else if annexb[i+2] == 0 && annexb[i+3] == 1 {
+					offset = 4 // 00 00 00 01
+				} else {
 					continue
 				}
-
-		// 4. Check "start code" (3 bytes size or 4 bytes size)
-		if b[i+2] == 1 {
-			if safeAppend {
-				// protect original slice from "damage"
-				b = bytes.Clone(b)
-				safeAppend = false
-			}
-
-			// convert start code from 3 bytes to 4 bytes
-			b = append(b, 0)
-			copy(b[i+1:], b[i:])
-			n++
-		} else if b[i+2] != 0 || b[i+3] != 1 {
-			i++
+			} else {
 				continue
 			}
-
-		// 5. Set size for previous AU
-		size := uint32(i - start - len(StartCode))
-		binary.BigEndian.PutUint32(b[start:], size)
-
-		start = i
-
-		i += minSize
+		} else {
+			i = len(annexb) // move i to data end
 		}
 
-	// 6. Set size for last AU
-	size := uint32(len(b) - start - len(StartCode))
-	binary.BigEndian.PutUint32(b[start:], size)
+		if start != 0 {
+			size := uint32(i - start)
+			avc = binary.BigEndian.AppendUint32(avc, size)
+			avc = append(avc, annexb[start:i]...)
+		}
 
-	return b
+		// sometimes FFmpeg put separator at the end
+		if i += offset; i == len(annexb) {
+			break
+		}
+
+		if isAUD(annexb[i]) {
+			start = 0 // skip this NALU
+		} else {
+			start = i // save this position
+		}
+	}
+
+	return
+}
+
+func isAUD(b byte) bool {
+	const h264 = 9
+	const h265 = 35 << 1
+	return b&0b0001_1111 == h264 || b&0b0111_1110 == h265
 }
 
 func DecodeAVCC(b []byte, safeClone bool) []byte {

pkg/kasa/producer.go

@@ -113,7 +113,7 @@ func (c *Producer) Start() error {
 					Header: rtp.Header{
 						Timestamp: uint32(ts * 90000),
 					},
-					Payload: annexb.EncodeToAVCC(body, false),
+					Payload: annexb.EncodeToAVCC(body),
 				}
 				video.WriteRTP(pkt)
 			}
@@ -168,7 +168,7 @@ func (c *Producer) probe() error {
 			}
 			waitVideo = false
 
-			body = annexb.EncodeToAVCC(body, false)
+			body = annexb.EncodeToAVCC(body)
 			codec := h264.AVCCToCodec(body)
 			media = &core.Media{
 				Kind:      core.KindVideo,

pkg/magic/bitstream/producer.go

@@ -25,7 +25,7 @@ func Open(r io.Reader) (*Producer, error) {
 		return nil, err
 	}
 
-	buf = annexb.EncodeToAVCC(buf, false) // won't break original buffer
+	buf = annexb.EncodeToAVCC(buf) // won't break original buffer
 
 	var codec *core.Codec
 	var format string
@@ -82,7 +82,7 @@ func (c *Producer) Start() error {
 			if len(c.Receivers) > 0 {
 				pkt := &rtp.Packet{
 					Header:  rtp.Header{Timestamp: core.Now90000()},
-					Payload: annexb.EncodeToAVCC(buf[:i], true),
+					Payload: annexb.EncodeToAVCC(buf[:i]),
 				}
 				c.Receivers[0].WriteRTP(pkt)
 

pkg/mpegts/demuxer.go

@@ -364,7 +364,7 @@ func (p *PES) GetPacket() (pkt *rtp.Packet) {
 			Header: rtp.Header{
 				PayloadType: p.StreamType,
 			},
-			Payload: annexb.EncodeToAVCC(p.Payload, false),
+			Payload: annexb.EncodeToAVCC(p.Payload),
 		}
 
 		if p.DTS != 0 {