hls muxer: update primary playlist in case SPS/PPS changed

internal/hls/muxer_primary_playlist.go

@@ -1,7 +1,6 @@
 package hls
 
 import (
-	"bytes"
 	"encoding/hex"
 	"io"
 	"strconv"
@@ -13,19 +12,20 @@ import (
 type muxerPrimaryPlaylist struct {
 	videoTrack *gortsplib.TrackH264
 	audioTrack *gortsplib.TrackAAC
-
-	cnt []byte
 }
 
 func newMuxerPrimaryPlaylist(
 	videoTrack *gortsplib.TrackH264,
 	audioTrack *gortsplib.TrackAAC,
 ) *muxerPrimaryPlaylist {
-	p := &muxerPrimaryPlaylist{
+	return &muxerPrimaryPlaylist{
 		videoTrack: videoTrack,
 		audioTrack: audioTrack,
 	}
+}
 
+func (p *muxerPrimaryPlaylist) reader() io.Reader {
+	return &asyncReader{generator: func() []byte {
 		var codecs []string
 
 		if p.videoTrack != nil {
@@ -40,15 +40,10 @@ func newMuxerPrimaryPlaylist(
 			codecs = append(codecs, "mp4a.40."+strconv.FormatInt(int64(p.audioTrack.Type()), 10))
 		}
 
-	p.cnt = []byte("#EXTM3U\n" +
+		return []byte("#EXTM3U\n" +
 			"#EXT-X-VERSION:3\n" +
 			"\n" +
 			"#EXT-X-STREAM-INF:BANDWIDTH=200000,CODECS=\"" + strings.Join(codecs, ",") + "\"\n" +
 			"stream.m3u8\n")
-
-	return p
-}
-
-func (p *muxerPrimaryPlaylist) reader() io.Reader {
-	return bytes.NewReader(p.cnt)
+	}}
 }