Implement actually decoding frames in VTVideoDecodeAccelerator.

content/common/gpu/media/vt_video_decode_accelerator.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_COMMON_GPU_MEDIA_VT_VIDEO_DECODE_ACCELERATOR_H_
 #define CONTENT_COMMON_GPU_MEDIA_VT_VIDEO_DECODE_ACCELERATOR_H_
 
+#include <map>
+#include <queue>
+
 #include "base/basictypes.h"
 #include "base/mac/scoped_cftyperef.h"
 #include "base/memory/ref_counted.h"
+#include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
 #include "base/message_loop/message_loop.h"
+#include "base/synchronization/lock.h"
 #include "base/threading/thread.h"
 #include "content/common/gpu/media/vt.h"
 #include "media/filters/h264_parser.h"
 #include "media/video/video_decode_accelerator.h"
 #include "ui/gfx/geometry/size.h"
 #include "ui/gl/gl_context_cgl.h"
 
 namespace base {
 class SingleThreadTaskRunner;
 }  // namespace base
@@ skipping 23 matching lines @@
   virtual bool CanDecodeOnIOThread() OVERRIDE;
 
   // Called by VideoToolbox when a frame is decoded.
   void Output(
       int32_t bitstream_id,
       OSStatus status,
       VTDecodeInfoFlags info_flags,
       CVImageBufferRef image_buffer);
 
  private:
+  struct DecodedFrame {
+    DecodedFrame(uint32_t bitstream_id, CVImageBufferRef image_buffer)
+        : bitstream_id(bitstream_id), image_buffer(image_buffer) {
+    }
+
+    int32_t bitstream_id;
+    CVImageBufferRef image_buffer;
+  };
+
   // Configure a VideoToolbox decompression session from parameter set NALUs.
   void ConfigureDecoder(
       const std::vector<const uint8_t*>& nalu_data_ptrs,
       const std::vector<size_t>& nalu_data_sizes);
 
   // Decode a frame of bitstream.
   void DecodeTask(const media::BitstreamBuffer);
 
+  // Send decoded frames if possible.
+  void SendPictures();
+
+  //
+  // GPU thread state.
+  //
   CGLContextObj cgl_context_;
-  media::VideoDecodeAccelerator::Client* client_;
-  base::Thread decoder_thread_;
+  // Texture IDs of assigned pictures.
+  std::map<int32_t, int32_t> texture_ids_;

[scherkus (not reviewing), 2014/07/16 18:18:51]

Chromium uses int32 w/o the _t

[sandersd (OOO until July 31), 2014/07/17 00:22:22]

My understanding is those types are deprecated.

https://code.google.com/p/chromium/codesearch#chromium/src/base/basictypes.h&...

[scherkus (not reviewing), 2014/07/17 02:08:25]

huh! go figure!

https://code.google.com/p/chromium/issues/detail?id=138542

+  // Pictures ready to be used.
+  std::queue<int32_t> picture_ids_;
+  // CVImageBuffers retained while they back textures.
+  std::map<int32_t, base::ScopedCFTypeRef<CVImageBufferRef>> retained_images_;
 
-  // Decoder configuration (used only on decoder thread).
+  //
+  // Decoder thread state.
+  //
   VTDecompressionOutputCallbackRecord callback_;
   base::ScopedCFTypeRef<CMFormatDescriptionRef> format_;
   base::ScopedCFTypeRef<VTDecompressionSessionRef> session_;
   media::H264Parser parser_;
   gfx::Size coded_size_;
 
-  // Member variables should appear before the WeakPtrFactory, to ensure
-  // that any WeakPtrs to Controller are invalidated before its members
-  // variable's destructors are executed, rendering them invalid.
+  //
+  // Lock-protected shared state.
+  //
+  base::Lock lock_;
+  int32_t frames_pending_decode_;

[scherkus (not reviewing), 2014/07/16 18:18:51]

for a count that shouldn't be negative, something like size_t would be more
appropriate

http://dev.chromium.org/developers/coding-style#TOC-Types

[sandersd (OOO until July 31), 2014/07/17 00:22:22]

Done.

+  std::queue<DecodedFrame> decoded_frames_;
+
+  //
+  // Unprotected shared state (set up and torn down on GPU thread).
+  //
+  scoped_refptr<base::SingleThreadTaskRunner> gpu_task_runner_;
+  scoped_ptr<base::WeakPtrFactory<media::VideoDecodeAccelerator::Client>>
+      weak_client_factory_;
+
+  // Declared after decoder thread state so that the thread will be stopped
+  // before its state is deleted.
+  base::Thread decoder_thread_;
+
+  // Declared last so that tasks are not posted after deletion starts.
   base::WeakPtrFactory<VTVideoDecodeAccelerator> weak_this_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(VTVideoDecodeAccelerator);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_COMMON_GPU_MEDIA_VT_VIDEO_DECODE_ACCELERATOR_H_