diff --git a/src/Codec/Transcode.cpp b/src/Codec/Transcode.cpp
index 049a1fde..f753803c 100644
--- a/src/Codec/Transcode.cpp
+++ b/src/Codec/Transcode.cpp
@@ -18,17 +18,16 @@
 #include <float.h>
 #include "Transcode.h"
 #include "Common/config.h"
-#include "Extension/Opus.h"
-#include "Extension/G711.h"
-#include "Extension/H264.h"
-#include "Extension/H265.h"
+#include "Extension/Factory.h"
 
+#define ADTS_HEADER_LEN 7
 #define MAX_DELAY_SECOND 3
 
 using namespace std;
 using namespace toolkit;
 
 namespace mediakit {
+extern int dumpAacConfig(const string &config, size_t length, uint8_t *out, size_t out_size);
 
 static string ffmpeg_err(int errnum) {
     char errbuf[AV_ERROR_MAX_STRING_SIZE];
@@ -1045,64 +1044,23 @@ void FFmpegEncoder::onEncode(AVPacket *packet) {
     // process frame
     if (!_cb)
         return;
-    switch (_codecId) {
-        case CodecH264: {
-            auto frame = FrameImp::create<H264Frame>();
-            frame->_dts = packet->dts;
-            frame->_pts = packet->pts;
-            frame->_buffer.assign((const char *)packet->data, packet->size);
-            frame->_prefix_size = prefixSize((const char *)packet->data, packet->size);
-            _cb(frame);
-            break;
+    if (_codecId == CodecAAC) {
+        auto frame = FrameImp::create<>();
+        frame->_codec_id = _codecId;
+        frame->_dts = packet->dts;
+        frame->_pts = packet->pts;
+        frame->_buffer.reserve(ADTS_HEADER_LEN + packet->size);
+        if (_context && _context->extradata && _context->extradata_size) {
+            uint8_t adts[ADTS_HEADER_LEN];
+            auto cfg = std::string((const char *)_context->extradata, _context->extradata_size);
+            dumpAacConfig(cfg, packet->size, adts, ADTS_HEADER_LEN);
+            frame->_prefix_size = ADTS_HEADER_LEN;
+            frame->_buffer.append((char*)adts, ADTS_HEADER_LEN);
         }
-        case CodecH265: {
-            auto frame = FrameImp::create<H265Frame>();
-            frame->_dts = packet->dts;
-            frame->_pts = packet->pts;
-            frame->_buffer.assign((const char *)packet->data, packet->size);
-            frame->_prefix_size = prefixSize((const char *)packet->data, packet->size);
-            _cb(frame);
-            break;
-        }
-        case CodecAAC: {
-            auto frame = FrameImp::create<>();
-            frame->_codec_id = _codecId;
-            frame->_dts = packet->dts;
-            frame->_pts = packet->pts;
-            frame->_buffer.reserve(ADTS_HEADER_LEN + packet->size);
-            if (_context && _context->extradata && _context->extradata_size) {
-                uint8_t adts[ADTS_HEADER_LEN];
-                auto cfg = std::string((const char *)_context->extradata, _context->extradata_size);
-                dumpAacConfig(cfg, packet->size, adts, ADTS_HEADER_LEN);
-                frame->_prefix_size = ADTS_HEADER_LEN;
-                frame->_buffer.append((char*)adts, ADTS_HEADER_LEN);
-            }
-            frame->_buffer.append((const char *)packet->data, packet->size);
-            _cb(frame);
-            break;
-        }
-        case CodecOpus:
-        case CodecG711A:
-        case CodecG711U: {
-            auto frame = FrameImp::create<>();
-            frame->_codec_id = _codecId;
-            frame->_dts = packet->dts;
-            frame->_pts = packet->pts;
-            frame->_buffer.assign((const char *)packet->data, packet->size);
-            _cb(frame);
-            break;
-        }
-        case CodecVP8:
-        case CodecVP9: {
-            auto frame = FrameImp::create<>();
-            frame->_codec_id = _codecId;
-            frame->_dts = packet->dts;
-            frame->_pts = packet->pts;
-            frame->_buffer.assign((const char *)packet->data, packet->size);
-            _cb(frame);
-            break;
-        }
-        default: break;
+        frame->_buffer.append((const char *)packet->data, packet->size);
+        _cb(frame);
+    } else {
+        _cb(Factory::getFrameFromPtr(_codecId, (const char*)packet->data, packet->size, packet->dts, packet->pts));
     }
 }
 
diff --git a/tests/test_audio_transcode.cpp b/tests/test_audio_transcode.cpp
index 3b7fe87d..5cd1b478 100644
--- a/tests/test_audio_transcode.cpp
+++ b/tests/test_audio_transcode.cpp
@@ -1,34 +1,35 @@
 #include "Codec/Transcode.h"
 #include "Record/MP4Demuxer.h"
 #include "Record/MP4Muxer.h"
-#include "Extension/AAC.h"
-#include "Extension/Opus.h"
-#include "Extension/G711.h"
 #include "Util/logger.h"
+
 using namespace mediakit;
 struct TransCtx {
     using Ptr = std::shared_ptr<TransCtx>;
     TransCtx(const char *prefix, CodecId codec) {
         char path[256];
-        Track::Ptr track;
+        int samplerate;
+        int channel = 1;
+        int bits = 16;
         switch (codec) {
         case CodecAAC:
-            track.reset(new AACTrack(44100, 1));
+            samplerate = 44100;
             sprintf(path, "%s_aac.mp4", prefix);
             break;
         case CodecOpus:
-            track.reset(new OpusTrack());
+            samplerate = 48000;
             sprintf(path, "%s_opus.mp4", prefix);
             break;
         case CodecG711A:
         case CodecG711U:
-            track.reset(new G711Track(codec, 8000, 1, 16));
+            samplerate = 8000;
             sprintf(path, "%s_711%c.mp4", prefix, codec == CodecG711A ? 'A' : 'U');
             break;
         default:
             return;
             break;
         }
+        Track::Ptr track = std::make_shared<AudioTrackImp>(codec, samplerate, channel, bits);
         file.reset(new MP4Muxer());
         file->openMP4(path);
         file->addTrack(track);
diff --git a/webrtc/RtcMediaSource.cpp b/webrtc/RtcMediaSource.cpp
index d25c8d0b..d547350a 100644
--- a/webrtc/RtcMediaSource.cpp
+++ b/webrtc/RtcMediaSource.cpp
@@ -68,17 +68,11 @@ bool RtcMediaSourceMuxer::inputFrame(const Frame::Ptr &frame)
         switch (frame->getCodecId())
         {
         case CodecAAC:
-          if (frame->prefixSize()) {
-            std::string cfg = makeAacConfig((uint8_t *)(frame->data()), frame->prefixSize());
-            track = std::make_shared<AACTrack>(cfg);
-          }
-          else {
-            track = std::make_shared<AACTrack>(44100, 2);
-          }
+          track = Factory::getTrackByCodecId(CodecAAC, 44100, 2, 16);
           break;
         case CodecG711A:
         case CodecG711U:
-          track.reset(new G711Track(frame->getCodecId()));
+          track = Factory::getTrackByCodecId(frame->getCodecId());
           break;
         default:
           break;
@@ -116,7 +110,7 @@ bool RtcMediaSourceMuxer::addTrack(const Track::Ptr & track)
 {
   Track::Ptr newTrack = track;
   if (_option.audio_transcode && needTransToOpus(track->getCodecId())) {
-    newTrack = std::make_shared<OpusTrack>();
+    newTrack = Factory::getTrackByCodecId(CodecOpus);
     GET_CONFIG(int, bitrate, General::kOpusBitrate);
     newTrack->setBitRate(bitrate);
     _audio_dec.reset(new FFmpegDecoder(track));
@@ -149,7 +143,7 @@ bool RtcMediaSourceImp::addTrack(const Track::Ptr &track)
   if (_muxer) {
     Track::Ptr newTrack = track;
     if (_option.audio_transcode && needTransToAac(track->getCodecId())) {
-      newTrack.reset(new AACTrack(44100, 2));
+      newTrack = Factory::getTrackByCodecId(CodecAAC, 44100, std::dynamic_pointer_cast<AudioTrack>(track)->getAudioChannel(), 16);
       GET_CONFIG(int, bitrate, General::kAacBitrate);
       newTrack->setBitRate(bitrate);
       _audio_dec.reset(new FFmpegDecoder(track));