work on decoder classes

decoders/ffmpegdecoder.h

@@ -8,17 +8,22 @@ class FFmpegDecoder : public Decoder
 public:
   FFmpegDecoder();
 
-  virtual bool Open();
-  virtual void Request(const rational& timecode);
-  virtual void Retrieve(uint8_t** buffer, int* linesize);
-  virtual void Close();
+  virtual bool Open() override;
+  virtual void Close() override;
+
+protected:
+  void FFmpegErr(int error_code);
+  void Error(const QString& s);
 
-private:
   AVFormatContext* fmt_ctx_;
   AVCodecContext* codec_ctx_;
-  AVStream* stream_;
+  AVStream* avstream_;
   AVPacket* pkt_;
   AVFrame* frame_;
+  AVDictionary* opts_;
+
+  QVector<int64_t> frame_index_;
+
 };
 
 #endif // FFMPEGDECODER_H