work on decoder classes

decoders/decoder.h

@@ -4,16 +4,33 @@
 #include <stdint.h>
 
 #include "global/rational.h"
+#include "project/footage.h"
+#include "frame.h"
 
-class Decoder
+/**
+ * @brief The Decoder class
+ *
+ * A decoder's is the main class for bringing external media into Olive. Its responsibilities are to serve as
+ * abstraction from codecs/decoders and provide complete frames. These frames can be video or audio data and are
+ * provided as Frame objects in shared pointers to alleviate the responsibility of memory handling.
+ *
+ * A decoder does NOT perform any pixel format conversion
+ */
+class Decoder : public QObject
 {
+  Q_OBJECT
 public:
-  Decoder();
+  Decoder(QObject* parent = nullptr);
+
+  Decoder(FootageStream* fs, QObject *parent = nullptr);
+
   virtual ~Decoder();
 
+  FootageStream* stream();
+  void set_stream(FootageStream* fs);
+
   virtual bool Open() = 0;
-  virtual void Request(const rational& timecode) = 0;
-  virtual void Retrieve(uint8_t** buffer, int* linesize) = 0;
+  virtual FramePtr Retrieve(const rational& timecode, const rational& length = 0) = 0;
   virtual void Close() = 0;
 
   // For video decoding
@@ -23,6 +40,10 @@ public:
 protected:
   bool open_;
 
+private:
+  FootageStream* stream_;
 };
 
+using DecoderPtr = std::shared_ptr<Decoder>;
+
 #endif // DECODER_H