diff --git a/track/aac.go b/track/aac.go
index 1536cb6..b20b50e 100644
--- a/track/aac.go
+++ b/track/aac.go
@@ -1,11 +1,9 @@
 package track
 
 import (
-	"fmt"
 	"io"
 	"net"
 
-	"github.com/bluenviron/mediacommon/pkg/bits"
 	"go.uber.org/zap"
 	"m7s.live/engine/v4/codec"
 	. "m7s.live/engine/v4/common"
@@ -18,9 +16,9 @@ func NewAAC(puber IPuber, stuff ...any) (aac *AAC) {
 	aac = &AAC{
 		Mode: 2,
 	}
-	aac.SizeLength = 13
-	aac.IndexLength = 3
-	aac.IndexDeltaLength = 3
+	aac.AACDecoder.SizeLength = 13
+	aac.AACDecoder.IndexLength = 3
+	aac.AACDecoder.IndexDeltaLength = 3
 	aac.CodecID = codec.CodecID_AAC
 	aac.Channels = 2
 	aac.SampleSize = 16
@@ -34,7 +32,6 @@ func NewAAC(puber IPuber, stuff ...any) (aac *AAC) {
 
 type AAC struct {
 	Audio
-
 	Mode      int       // 1为lbr，2为hbr
 	fragments *util.BLL // 用于处理不完整的AU,缺少的字节数
 }
@@ -72,97 +69,16 @@ func (aac *AAC) WriteADTS(ts uint32, b util.IBytes) {
 func (aac *AAC) WriteRTPFrame(rtpItem *LIRTP) {
 	aac.Value.RTP.Push(rtpItem)
 	frame := &rtpItem.Value
-	if len(frame.Payload) < 2 {
-		// aac.fragments = aac.fragments[:0]
+	au, err := aac.AACDecoder.Decode(frame.Packet)
+	if err != nil {
+		aac.Error("decode error", zap.Error(err))
 		return
 	}
-	if aac.SampleRate != 90000 {
-		aac.generateTimestamp(uint32(uint64(frame.Timestamp) * 90000 / uint64(aac.SampleRate)))
-	}
-	auHeaderLen := util.ReadBE[int](frame.Payload[:2]) //通常为16，即一个AU Header的长度
-	if auHeaderLen == 0 {
-		aac.Value.AUList.Push(aac.BytesPool.GetShell(frame.Payload[:2]))
-		aac.Flush()
-	} else {
-		payload := frame.Payload[2:]
-		// AU-headers
-		dataLens, err := aac.readAUHeaders(payload, auHeaderLen)
-		if err != nil {
-			// discard pending fragmented packets
-			return
-		}
-
-		pos := (auHeaderLen >> 3)
-		if (auHeaderLen % 8) != 0 {
-			pos++
-		}
-		payload = payload[pos:]
-
-		if aac.fragments == nil {
-			if frame.Header.Marker {
-				// AUs
-				for _, dataLen := range dataLens {
-					if len(payload) < int(dataLen) {
-						aac.fragments = &util.BLL{}
-						aac.fragments.Push(aac.BytesPool.GetShell(payload))
-						// aac.fragments = aac.fragments[:0]
-						// aac.Error("payload is too short 1", zap.Int("dataLen", int(dataLen)), zap.Int("len", len(payload)))
-						return
-					}
-					aac.AppendAuBytes(payload[:dataLen])
-					payload = payload[dataLen:]
-				}
-			} else {
-				if len(dataLens) != 1 {
-					// aac.fragments = aac.fragments[:0]
-					aac.Error("a fragmented packet can only contain one AU")
-					return
-				}
-				aac.fragments = &util.BLL{}
-				// if len(payload) < int(dataLens[0]) {
-				// 	aac.fragments = aac.fragments[:0]
-				// 	aac.Error("payload is too short 2", zap.Int("dataLen", int(dataLens[0])), zap.Int("len", len(payload)))
-				// 	return
-				// }
-				aac.fragments.Push(aac.BytesPool.GetShell(payload))
-				// aac.fragments = append(aac.fragments, payload[:dataLens[0]])
-				return
-			}
-		} else {
-			// we are decoding a fragmented AU
-			if len(dataLens) != 1 {
-				aac.fragments.Recycle()
-				aac.fragments = nil
-				// aac.fragments = aac.fragments[:0]
-				aac.Error("a fragmented packet can only contain one AU")
-				return
-			}
-
-			// if len(payload) < int(dataLens[0]) {
-			// 	aac.fragments = aac.fragments[:0]
-			// 	aac.Error("payload is too short 3", zap.Int("dataLen", int(dataLens[0])), zap.Int("len", len(payload)))
-			// 	return
-			// }
-
-			// if fragmentedSize := util.SizeOfBuffers(aac.fragments) + int(dataLens[0]); fragmentedSize > 5*1024 {
-			// 	aac.fragments = aac.fragments[:0] // discard pending fragmented packets
-			// 	aac.Error(fmt.Sprintf("AU size (%d) is too big (maximum is %d)", fragmentedSize, 5*1024))
-			// 	return
-			// }
-
-			// aac.fragments = append(aac.fragments, payload[:dataLens[0]])
-			aac.fragments.Push(aac.BytesPool.GetShell(payload))
-			if !frame.Header.Marker {
-				return
-			}
-			if uint64(aac.fragments.ByteLength) != dataLens[0] {
-				aac.Error("fragmented AU size is not correct", zap.Uint64("dataLen", dataLens[0]), zap.Int("len", aac.fragments.ByteLength))
-			}
-			aac.Value.AUList.PushValue(aac.fragments)
-			// aac.AppendAuBytes(aac.fragments...)
-
-			aac.fragments = nil
+	if len(au) > 0 {
+		if aac.SampleRate != 90000 {
+			aac.generateTimestamp(uint32(uint64(frame.Timestamp) * 90000 / uint64(aac.SampleRate)))
 		}
+		aac.AppendAuBytes(au...)
 		aac.Flush()
 	}
 }
@@ -205,62 +121,3 @@ func (aac *AAC) CompleteRTP(value *AVFrame) {
 	}
 	aac.PacketizeRTP(packets...)
 }
-
-func (aac *AAC) readAUHeaders(buf []byte, headersLen int) ([]uint64, error) {
-	firstRead := false
-
-	count := 0
-	for i := 0; i < headersLen; {
-		if i == 0 {
-			i += aac.SizeLength
-			i += aac.IndexLength
-		} else {
-			i += aac.SizeLength
-			i += aac.IndexDeltaLength
-		}
-		count++
-	}
-
-	dataLens := make([]uint64, count)
-
-	pos := 0
-	i := 0
-
-	for headersLen > 0 {
-		dataLen, err := bits.ReadBits(buf, &pos, aac.SizeLength)
-		if err != nil {
-			return nil, err
-		}
-		headersLen -= aac.SizeLength
-
-		if !firstRead {
-			firstRead = true
-			if aac.IndexLength > 0 {
-				auIndex, err := bits.ReadBits(buf, &pos, aac.IndexLength)
-				if err != nil {
-					return nil, err
-				}
-				headersLen -= aac.IndexLength
-
-				if auIndex != 0 {
-					return nil, fmt.Errorf("AU-index different than zero is not supported")
-				}
-			}
-		} else if aac.IndexDeltaLength > 0 {
-			auIndexDelta, err := bits.ReadBits(buf, &pos, aac.IndexDeltaLength)
-			if err != nil {
-				return nil, err
-			}
-			headersLen -= aac.IndexDeltaLength
-
-			if auIndexDelta != 0 {
-				return nil, fmt.Errorf("AU-index-delta different than zero is not supported")
-			}
-		}
-
-		dataLens[i] = dataLen
-		i++
-	}
-
-	return dataLens, nil
-}
diff --git a/track/audio.go b/track/audio.go
index 68545ab..b2010b5 100644
--- a/track/audio.go
+++ b/track/audio.go
@@ -1,6 +1,7 @@
 package track
 
 import (
+	"github.com/bluenviron/gortsplib/v4/pkg/format/rtpmpeg4audio"
 	"go.uber.org/zap"
 	"m7s.live/engine/v4/codec"
 	. "m7s.live/engine/v4/common"
@@ -9,14 +10,12 @@ import (
 
 type Audio struct {
 	Media
-	CodecID          codec.AudioCodecID
-	Channels         byte
-	SampleSize       byte
-	SizeLength       int // 通常为13
-	IndexLength      int
-	IndexDeltaLength int
-	AVCCHead         []byte // 音频包在AVCC格式中，AAC会有两个字节，其他的只有一个字节
+	CodecID    codec.AudioCodecID
+	Channels   byte
+	SampleSize byte
+	AVCCHead   []byte // 音频包在AVCC格式中，AAC会有两个字节，其他的只有一个字节
 	codec.AudioSpecificConfig
+	AACDecoder rtpmpeg4audio.Decoder
 }
 
 func (a *Audio) Attach() {
diff --git a/util/ring-writer.go b/util/ring-writer.go
index fae4806..b65e551 100644
--- a/util/ring-writer.go
+++ b/util/ring-writer.go
@@ -81,7 +81,6 @@ func (rb *RingWriter[T, F]) Reduce(size int) {
 	p := rb.Unlink(size)
 	pSize := size
 	rb.Size -= size
-	defer rb.recycle(p)
 	for i := 0; i < size; i++ {
 		if p.Value.StartWrite() {
 			p.Value.Reset()
@@ -90,6 +89,7 @@ func (rb *RingWriter[T, F]) Reduce(size int) {
 		} else {
 			p.Value.Reset()
 			if pSize == 1 {
+				// last one，无法删除最后一个节点，直接返回即可
 				return
 			}
 			p = p.Prev()
@@ -98,6 +98,7 @@ func (rb *RingWriter[T, F]) Reduce(size int) {
 		}
 		p = p.Next()
 	}
+	rb.recycle(p)
 }
 
 func (rb *RingWriter[T, F]) Dispose() {