player增加speed，pause扩展，seek支持秒级定位，MP4按时间戳生成文件

src/Common/MediaSource.h

@@ -67,6 +67,10 @@ public:
 
     // 通知拖动进度条
     virtual bool seekTo(MediaSource &sender, uint32_t stamp) { return false; }
+    // 通知暂停
+    virtual bool pause(MediaSource& sender) { return false; }
+    // 通知倍数
+    virtual bool speed(MediaSource& sender, float speed) { return false; }
     // 通知其停止产生流
     virtual bool close(MediaSource &sender, bool force) { return false; }
     // 获取观看总人数
@@ -106,6 +110,8 @@ public:
     std::shared_ptr<SockInfo> getOriginSock(MediaSource &sender) const override;
 
     bool seekTo(MediaSource &sender, uint32_t stamp) override;
+    bool pause(MediaSource& sender) override;
+    bool speed(MediaSource& sender, float speed) override;
     bool close(MediaSource &sender, bool force) override;
     int totalReaderCount(MediaSource &sender) override;
     void onReaderChanged(MediaSource &sender, int size) override;
@@ -249,6 +255,11 @@ public:
 
     // 拖动进度条
     bool seekTo(uint32_t stamp);
+    //暂停
+    bool pause();
+
+    //倍数播放
+    bool speed(float speed);
     // 关闭该流
     bool close(bool force);
     // 该流观看人数变化