began base encoder type for abstracting around exporting

Essentially the same principle as Decoders but somewhat different functionality.

app/encoder/encoder.h

@@ -0,0 +1,49 @@
+#ifndef ENCODER_H
+#define ENCODER_H
+
+#include <memory>
+#include <QString>
+
+#include "common/constructors.h"
+#include "render/audioparams.h"
+#include "render/videoparams.h"
+
+class Encoder;
+using EncoderPtr = std::shared_ptr<Encoder>;
+
+class EncodingParams {
+public:
+  EncodingParams();
+
+  void SetFilename(const QString& filename);
+  void EnableVideo(const VideoParams& video_params, const QString& vcodec);
+  void EnableAudio(const AudioParams& audio_params, const QString& acodec);
+
+private:
+  QString filename_;
+
+  QString video_codec_;
+  bool video_enabled_;
+  VideoParams video_params_;
+
+  QString audio_codec_;
+  bool audio_enabled_;
+  AudioParams audio_params_;
+};
+
+class Encoder
+{
+public:
+  Encoder(const EncodingParams& params);
+
+  DISABLE_COPY_MOVE(Encoder)
+
+  virtual bool Open() = 0;
+
+  virtual void Close() = 0;
+
+private:
+  EncodingParams params_;
+};
+
+#endif // ENCODER_H