fix: refactor Ogg alignment and header injection to ensure perfect bitstream continuity

Author: Datanoise

relay/relay.go

@@ -334,6 +334,12 @@ func (s *Stream) Subscribe(id string, burstSize int) (int64, chan struct{}) {
 		validStart := s.Buffer.Head - s.Buffer.Size
 		if validStart < 0 { validStart = 0 }
 
+		// If we have an OggHead persistent storage, we want to start reading 
+		// from the Buffer AFTER the initial headers to avoid duplicates.
+		if s.OggHeaderOffset > start {
+			start = s.OggHeaderOffset
+		}
+
 		if start < validStart { start = validStart }
 
 		bestAlign := s.LastPageOffset
@@ -347,7 +353,7 @@ func (s *Stream) Subscribe(id string, burstSize int) (int64, chan struct{}) {
 		}
 		if found {
 			start = bestAlign
-		} else if bestAlign >= validStart {
+		} else if bestAlign >= validStart && bestAlign > 0 {
 			start = bestAlign
 		} else {
 			start = s.Buffer.Head // Fallback to now if nothing valid found

relay/transcode.go

@@ -227,16 +227,17 @@ func (tm *TranscoderManager) encodeOpus(ctx context.Context, inst *TranscoderIns
 	serial := uint32(time.Now().UnixNano())
 	pw := ogg.NewPacketWriter(writer, serial)
 
-	// ID Header
+	// 1. ID Header
 	head := ogg.OpusHead{
 		Version:         1,
 		Channels:        uint8(channels),
 		InputSampleRate: uint32(sampleRate),
 	}
 	headPacket, _ := ogg.BuildOpusHeadPacket(head)
 	pw.WritePacket(headPacket, 0, true, false)
+	pw.Flush()
 
-	// Tags Header
+	// 2. Tags Header
 	tags := ogg.OpusTags{Vendor: "tinyice-opus"}
 	tagsPacket, _ := ogg.BuildOpusTagsPacket(tags)
 	pw.WritePacket(tagsPacket, 0, false, false)

server/server.go

@@ -913,20 +913,13 @@ func (s *Server) serveStreamData(w http.ResponseWriter, r *http.Request, stream
 	defer stream.Unsubscribe(id)
 
 	if stream.OggHead != nil {
-		// If we are starting from the very beginning of the stream (or burst includes start)
-		// we don't send OggHead because it's already in the buffer at OggHeaderOffset.
-		// BUT for simplicity and robustness, we ALWAYS send OggHead first and then 
-		// ensure our offset is correctly aligned AFTER the headers in the buffer.
+		// Always send stored headers for Ogg/Opus
 		if _, err := w.Write(stream.OggHead); err != nil {
 			return false
 		}
-		
-		// If our starting offset is before where the actual audio data starts, 
-		// skip the header part of the buffer to avoid sending them twice.
-		if offset < stream.OggHeaderOffset {
-			offset = stream.OggHeaderOffset
-		}
-		logrus.Debugf("Ogg Listener %s: Sending stored headers, then starting burst at %d (HeaderEnd: %d)", id, offset, stream.OggHeaderOffset)
+		// The 'offset' returned by Subscribe is already intelligently aligned 
+		// AFTER the headers in the buffer if OggHeaderOffset was set.
+		logrus.Debugf("Ogg Listener %s: Sending stored headers (%d bytes), then starting burst at %d", id, len(stream.OggHead), offset)
 	}
 
 	buf := make([]byte, 16384)