Implement a reorder queue 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 <stdint.h>
 
 #include <map>
 #include <queue>
 
 #include "base/mac/scoped_cftyperef.h"
 #include "base/memory/linked_ptr.h"
 #include "base/memory/weak_ptr.h"
 #include "base/message_loop/message_loop.h"
 #include "base/threading/thread.h"
 #include "base/threading/thread_checker.h"
+#include "content/common/gpu/media/h264_dpb.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 36 matching lines @@
     TASK_FRAME,
     TASK_FLUSH,
     TASK_RESET,
     TASK_DESTROY,
   };
 
   struct Frame {
     Frame(int32_t bitstream_id);
     ~Frame();
 
+    // ID of the bitstream buffer this Frame will be decoded from.
     int32_t bitstream_id;
-    base::ScopedCFTypeRef<CVImageBufferRef> image;
+
+    // Relative presentation order of this frame (see AVC spec).
+    // TODO(sandersd): Reorder window size.
+    int32_t pic_order_cnt;
+
+    // Size of the decoded frame.
     // TODO(sandersd): visible_rect.
     gfx::Size coded_size;
+
+    // VideoToolbox decoded image, if decoding was successful.
+    base::ScopedCFTypeRef<CVImageBufferRef> image;
   };
 
   struct Task {
     Task(TaskType type);
     ~Task();
 
     TaskType type;
     linked_ptr<Frame> frame;
   };
 
   //
   // Methods for interacting with VideoToolbox. Run on |decoder_thread_|.
   //
+
   // Set up VideoToolbox using the current SPS and PPS. Returns true or calls
   // NotifyError() before returning false.
   bool ConfigureDecoder();
 
   // Wait for VideoToolbox to output all pending frames. Returns true or calls
   // NotifyError() before returning false.
   bool FinishDelayedFrames();
 
   // |frame| is owned by |pending_frames_|.
   void DecodeTask(const media::BitstreamBuffer&, Frame* frame);
   void DecodeDone(Frame* frame);
 
   //
   // Methods for interacting with |client_|. Run on |gpu_task_runner_|.
   //
   void NotifyError(Error error);
 
   // |type| is the type of task that the flush will complete, one of TASK_FLUSH,
   // TASK_RESET, or TASK_DESTROY.
   void QueueFlush(TaskType type);
   void FlushTask(TaskType type);
   void FlushDone(TaskType type);
 
-  // Attempt to make progress on |pending_tasks_|.
-  void ProcessTasks();
+  // Try to make progress on tasks in the |task_queue_| or sending frames in the
+  // |reorder_queue_|.
+  void ProcessWorkQueues();
 
-  // These methods returns true if the task was completed, false if it couldn't
-  // be completed yet.
-  bool ProcessTask(const Task& task);
+  // These methods returns true if a task was completed, false otherwise.
+  bool ProcessTaskQueue();
+  bool ProcessReorderQueue();
   bool ProcessFrame(const Frame& frame);
   bool SendFrame(const Frame& frame);
 
   //
   // GPU thread state.
   //
   CGLContextObj cgl_context_;
   base::Callback<bool(void)> make_context_current_;
   media::VideoDecodeAccelerator::Client* client_;
   State state_;
 
   // Queue of pending flush tasks. This is used to drop frames when a reset
   // is pending.
   std::queue<TaskType> pending_flush_tasks_;
 
   // Queue of tasks to complete in the GPU thread.
-  std::queue<Task> pending_tasks_;
+  std::queue<Task> task_queue_;
+
+  // Utility class to define the order of frames in the reorder queue.
+  struct FrameOrder {
+    bool operator()(
+        const linked_ptr<Frame>& lhs,
+        const linked_ptr<Frame>& rhs) const;
+  };
+
+  // Queue of decoded frames in presentation order.
+  std::priority_queue<linked_ptr<Frame>,
+                      std::vector<linked_ptr<Frame>>,
+                      FrameOrder> reorder_queue_;
 
   // Size of assigned picture buffers.
   gfx::Size picture_size_;
 
   // Queue of frames that have not yet been decoded; maintains ownership of the
   // Frame objects while they flow through VideoToolbox.
   std::queue<linked_ptr<Frame>> pending_frames_;
 
   // Set of assigned bitstream IDs, so that Destroy() can release them all.
   std::set<int32_t> assigned_bitstream_ids_;
@@ skipping 14 matching lines @@
 
   //
   // Decoder thread state.
   //
   VTDecompressionOutputCallbackRecord callback_;
   base::ScopedCFTypeRef<CMFormatDescriptionRef> format_;
   base::ScopedCFTypeRef<VTDecompressionSessionRef> session_;
   media::H264Parser parser_;
   gfx::Size coded_size_;
 
+  int last_sps_id_;
   std::vector<uint8_t> last_sps_;
   std::vector<uint8_t> last_spsext_;
+  int last_pps_id_;
   std::vector<uint8_t> last_pps_;
 
   //
   // Shared state (set up and torn down on GPU thread).
   //
   scoped_refptr<base::SingleThreadTaskRunner> gpu_task_runner_;
   base::ThreadChecker gpu_thread_checker_;
   base::WeakPtr<VTVideoDecodeAccelerator> weak_this_;
   base::Thread decoder_thread_;
 
   // Declared last to ensure that all weak pointers are invalidated before
   // other destructors run.
   base::WeakPtrFactory<VTVideoDecodeAccelerator> weak_this_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(VTVideoDecodeAccelerator);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_COMMON_GPU_MEDIA_VT_VIDEO_DECODE_ACCELERATOR_H_