fix: when rtmp sequence header change,mp4 record two diffent sequence header into the same mp4 file.

Author: pggiroro

plugin/mp4/pkg/record.go

@@ -296,18 +296,18 @@ func (r *Recorder) Run() (err error) {
 
 		if vt == nil {
 			vt = sub.VideoReader.Track
-			switch vt.ICodecCtx.GetBase().(type) {
+			switch video.ICodecCtx.GetBase().(type) {
 			case *codec.H264Ctx:
 				track := r.muxer.AddTrack(box.MP4_CODEC_H264)
 				videoTrack = track
-				track.ICodecCtx = vt.ICodecCtx
+				track.ICodecCtx = video.ICodecCtx
 			case *codec.H265Ctx:
 				track := r.muxer.AddTrack(box.MP4_CODEC_H265)
 				videoTrack = track
-				track.ICodecCtx = vt.ICodecCtx
+				track.ICodecCtx = video.ICodecCtx
 			}
 		}
-		ctx := vt.ICodecCtx.(pkg.IVideoCodecCtx)
+		ctx := video.ICodecCtx.(pkg.IVideoCodecCtx)
 		if videoTrackCtx, ok := videoTrack.ICodecCtx.(pkg.IVideoCodecCtx); ok && videoTrackCtx != ctx {
 			width, height := uint32(ctx.Width()), uint32(ctx.Height())
 			oldWidth, oldHeight := uint32(videoTrackCtx.Width()), uint32(videoTrackCtx.Height())
@@ -322,6 +322,17 @@ func (r *Recorder) Run() (err error) {
 			at, vt = nil, nil
 			if vr := sub.VideoReader; vr != nil {
 				vr.ResetAbsTime()
+				vt = vr.Track
+				switch video.ICodecCtx.GetBase().(type) {
+				case *codec.H264Ctx:
+					track := r.muxer.AddTrack(box.MP4_CODEC_H264)
+					videoTrack = track
+					track.ICodecCtx = video.ICodecCtx
+				case *codec.H265Ctx:
+					track := r.muxer.AddTrack(box.MP4_CODEC_H265)
+					videoTrack = track
+					track.ICodecCtx = video.ICodecCtx
+				}
 			}
 			if ar := sub.AudioReader; ar != nil {
 				ar.ResetAbsTime()

plugin/mp4/pkg/track.go

@@ -73,9 +73,14 @@ func (track *Track) makeElstBox() *EditListBox {
 	// 	elst.entrys.entrys[0].mediaRateFraction = 0
 	// }
 
-	//简单起见，mediaTime先固定为0,即不延迟播放
+	//使用第一个sample的时间戳作为MediaTime，确保时间轴对齐
+	firstTimestamp := track.Samplelist[0].Timestamp
+	firstCTS := track.Samplelist[0].CTS
+	mediaTime := int64(firstTimestamp) + int64(firstCTS)
+	
 	entrys[entryCount-1].SegmentDuration = uint64(track.Duration)
-	entrys[entryCount-1].MediaTime = 0
+	// MediaTime应该是第一个sample的PTS (DTS + CTS)
+	entrys[entryCount-1].MediaTime = mediaTime
 	entrys[entryCount-1].MediaRateInteger = 0x0001
 	entrys[entryCount-1].MediaRateFraction = 0