ffmpegframepool: implemented functional frame pool

Includes splitting off core functionality to a base MemoryPool class that can
be re-used later if necessary.

app/codec/ffmpeg/ffmpegdecoder.h

@@ -35,8 +35,8 @@ extern "C" {
 #include "audio/sampleformat.h"
 #include "avframeptr.h"
 #include "codec/decoder.h"
-#include "codec/framepool.h"
 #include "codec/waveoutput.h"
+#include "ffmpegframepool.h"
 #include "project/item/footage/videostream.h"
 
 OLIVE_NAMESPACE_ENTER
@@ -56,7 +56,7 @@ public:
   bool CacheWillContainTime(const int64_t& t) const;
   bool CacheCouldContainTime(const int64_t& t) const;
   bool CacheIsEmpty() const;
-  FramePool::ElementPtr GetFrameFromCache(const int64_t& t) const;
+  FFmpegFramePool::ElementPtr GetFrameFromCache(const int64_t& t) const;
 
   void RemoveFramesBefore(const qint64& t);
 
@@ -65,7 +65,7 @@ public:
 
   void ClearFrameCache();
 
-  FramePool::ElementPtr RetrieveFrame(const int64_t &target_ts, bool cache_is_locked);
+  FFmpegFramePool::ElementPtr RetrieveFrame(const int64_t &target_ts, bool cache_is_locked);
 
   /**
    * @brief Uses the FFmpeg API to retrieve a packet (stored in pkt_) and decode it (stored in frame_)
@@ -96,8 +96,8 @@ private:
 
   QWaitCondition cache_wait_cond_;
   QMutex cache_lock_;
-  QList<FramePool::ElementPtr> cached_frames_;
-  FramePool frame_pool_;
+  QList<FFmpegFramePool::ElementPtr> cached_frames_;
+  FFmpegFramePool frame_pool_;
 
   int64_t cache_target_time_;
 
@@ -160,13 +160,13 @@ private:
 
   void UnconditionalAudioIndex(const QAtomicInt* cancelled);
 
-  void CacheFrameToDisk(AVFrame* f);
-
   void ClearResources();
 
-  void SetupScaler(const int& divider);
+  void InitScaler(int divider);
   void FreeScaler();
 
+  SwsContext* scale_ctx_;
+  int scale_divider_;
   AVPixelFormat src_pix_fmt_;
   AVPixelFormat ideal_pix_fmt_;
   PixelFormat::Format native_pix_fmt_;
@@ -175,9 +175,6 @@ private:
   rational aspect_ratio_;
   int64_t start_time_;
 
-  SwsContext* scale_ctx_;
-  int scale_divider_;
-
   QTimer clear_timer_;
 
   FFmpegDecoderInstance* our_instance_;