优化frame性能及整理代码

src/Extension/G711.h

@@ -21,53 +21,12 @@ namespace mediakit{
  */
 class G711Track : public AudioTrackImp{
 public:
-    typedef std::shared_ptr<G711Track> Ptr;
+    using Ptr = std::shared_ptr<G711Track>;
     G711Track(CodecId codecId,int sample_rate, int channels, int sample_bit) : AudioTrackImp(codecId,sample_rate,channels,sample_bit){}
 
 private:
-    //克隆该Track
-    Track::Ptr clone() override {
-        return std::make_shared<std::remove_reference<decltype(*this)>::type >(*this);
-    }
-    //生成sdp
-    Sdp::Ptr getSdp() override ;
-};
-
-/**
- * G711类型SDP
- */
-class G711Sdp : public Sdp {
-public:
-    /**
-     * G711采样率固定为8000
-     * @param codecId G711A G711U
-     * @param sample_rate 音频采样率
-     * @param payload_type rtp payload
-     * @param bitrate 比特率
-     */
-    G711Sdp(CodecId codecId,
-            int sample_rate,
-            int channels,
-            int bitrate = 128,
-            int payload_type = 98) : Sdp(sample_rate,payload_type), _codecId(codecId){
-        _printer << "m=audio 0 RTP/AVP " << payload_type << "\r\n";
-        if (bitrate) {
-            _printer << "b=AS:" << bitrate << "\r\n";
-        }
-        _printer << "a=rtpmap:" << payload_type << (codecId == CodecG711A ? " PCMA/" : " PCMU/") << sample_rate  << "/" << channels << "\r\n";
-        _printer << "a=control:trackID=" << (int)TrackAudio << "\r\n";
-    }
-
-    string getSdp() const override {
-        return _printer;
-    }
-
-    CodecId getCodecId() const override {
-        return _codecId;
-    }
-private:
-    _StrPrinter _printer;
-    CodecId _codecId;
+    Sdp::Ptr getSdp() override;
+    Track::Ptr clone() override;
 };
 
 }//namespace mediakit