Revert "忽略某些流声明存在却没实质数据的track"

This reverts commit b4207240.

src/Extension/Track.h

@@ -147,12 +147,7 @@ public:
      * 是否已经初始化
      */
     bool ready() override {
-        return _ready;
-    }
-
-    bool inputFrame(const Frame::Ptr &frame) override {
-        _ready = true;
-        return AudioTrack::inputFrame(frame);
+        return true;
     }
 
     /**
@@ -176,7 +171,6 @@ public:
         return _channels;
     }
 private:
-    bool _ready = false;
     CodecId _codecid;
     int _sample_rate;
     int _channels;