diff --git a/demuxer.go b/demuxer.go
index f6e8a29..3d278d4 100644
--- a/demuxer.go
+++ b/demuxer.go
@@ -30,7 +30,11 @@ type Demuxer struct {
 	streams []*Stream
 }
 
-func (self *Demuxer) Streams() (streams []av.CodecData) {
+func (self *Demuxer) Streams() (streams []av.CodecData, err error) {
+	if len(self.streams) == 0 {
+		err = fmt.Errorf("ts: no streams")
+		return
+	}
 	for _, stream := range self.streams {
 		streams = append(streams, stream)
 	}
@@ -116,7 +120,12 @@ func (self *Demuxer) readTSPacket() (err error) {
 						}
 					}
 					self.pktque = &pktqueue.Queue{}
-					self.pktque.Alloc(self.Streams())
+
+					var streams []av.CodecData
+					if streams, err = self.Streams(); err != nil {
+						return
+					}
+					self.pktque.Alloc(streams)
 					self.pktque.Poll = self.poll
 				}
 			}
diff --git a/muxer.go b/muxer.go
index ec6ee8b..7e95420 100644
--- a/muxer.go
+++ b/muxer.go
@@ -134,7 +134,7 @@ func (self *Muxer) WritePacket(streamIndex int, pkt av.Packet) (err error) {
 	stream := self.streams[streamIndex]
 
 	if stream.Type() == av.AAC {
-		codec := stream.CodecData.(av.AACCodecData)
+		codec := stream.CodecData.(aacparser.CodecData)
 		data := pkt.Data
 		if !aacparser.IsADTSFrame(data) {
 			data = append(codec.MakeADTSHeader(1024, len(data)), data...)
@@ -157,7 +157,7 @@ func (self *Muxer) WritePacket(streamIndex int, pkt av.Packet) (err error) {
 		stream.time += pkt.Duration
 
 	} else if stream.Type() == av.H264 {
-		codec := stream.CodecData.(av.H264CodecData)
+		codec := stream.CodecData.(h264parser.CodecData)
 		buf := &bytes.Buffer{}
 		pes := PESHeader{
 			StreamId: StreamIdH264,