Save-to-webm: use timestamp from samplebuilder

This avoids desyncing by accumulating drift.
pion · Sep 30, 2022 · 4f95b29 · 4f95b29
1 parent 62ca572
commit 4f95b29
Showing 1 changed file with 16 additions and 9 deletions.
diff --git a/save-to-webm/main.go b/save-to-webm/main.go
@@ -32,9 +32,10 @@ func main() {
 }
 
 type webmSaver struct {
-	audioWriter, videoWriter       webm.BlockWriteCloser
-	audioBuilder, videoBuilder     *samplebuilder.SampleBuilder
-	audioTimestamp, videoTimestamp time.Duration
+	audioWriter, videoWriter                 webm.BlockWriteCloser
+	audioBuilder, videoBuilder               *samplebuilder.SampleBuilder
+	hasStartAudioOffset, hasStartVideoOffset bool
+	startAudioOffset, startVideoOffset       uint32
 }
 
 func newWebmSaver() *webmSaver {
@@ -61,13 +62,16 @@ func (s *webmSaver) PushOpus(rtpPacket *rtp.Packet) {
 	s.audioBuilder.Push(rtpPacket)
 
 	for {
-		sample := s.audioBuilder.Pop()
+		sample, audioTimestamp := s.audioBuilder.PopWithTimestamp()
 		if sample == nil {
 			return
 		}
 		if s.audioWriter != nil {
-			s.audioTimestamp += sample.Duration
-			if _, err := s.audioWriter.Write(true, int64(s.audioTimestamp/time.Millisecond), sample.Data); err != nil {
+			if !s.hasStartAudioOffset {
+				s.startAudioOffset = audioTimestamp
+				s.hasStartAudioOffset = true
+			}
+			if _, err := s.audioWriter.Write(true, int64((audioTimestamp-s.startAudioOffset)/48), sample.Data); err != nil {
 				panic(err)
 			}
 		}
@@ -77,7 +81,7 @@ func (s *webmSaver) PushVP8(rtpPacket *rtp.Packet) {
 	s.videoBuilder.Push(rtpPacket)
 
 	for {
-		sample := s.videoBuilder.Pop()
+		sample, videoTimestamp := s.videoBuilder.PopWithTimestamp()
 		if sample == nil {
 			return
 		}
@@ -95,8 +99,11 @@ func (s *webmSaver) PushVP8(rtpPacket *rtp.Packet) {
 			}
 		}
 		if s.videoWriter != nil {
-			s.videoTimestamp += sample.Duration
-			if _, err := s.videoWriter.Write(videoKeyframe, int64(s.videoTimestamp/time.Millisecond), sample.Data); err != nil {
+			if !s.hasStartVideoOffset {
+				s.startVideoOffset = videoTimestamp
+				s.hasStartVideoOffset = true
+			}
+			if _, err := s.videoWriter.Write(videoKeyframe, int64((videoTimestamp-s.startVideoOffset)/90), sample.Data); err != nil {
 				panic(err)
 			}
 		}