H264 HW encode using VideoToolbox

content/common/gpu/media/vt_video_encode_accelerator_mac.h

-// Copyright 2013 The Chromium Authors. All rights reserved.
+// Copyright 2016 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_ANDROID_VIDEO_ENCODE_ACCELERATOR_H_
-#define CONTENT_COMMON_GPU_MEDIA_ANDROID_VIDEO_ENCODE_ACCELERATOR_H_
+#ifndef CONTENT_COMMON_GPU_MEDIA_VT_VIDEO_ENCODE_ACCELERATOR_MAC_H_
+#define CONTENT_COMMON_GPU_MEDIA_VT_VIDEO_ENCODE_ACCELERATOR_MAC_H_
 
-#include <stddef.h>
-#include <stdint.h>
-
-#include <list>
-#include <queue>
-#include <vector>
-
-#include "base/macros.h"
-#include "base/memory/weak_ptr.h"
-#include "base/threading/thread_checker.h"
-#include "base/timer/timer.h"
-#include "base/tuple.h"
+#include "base/mac/scoped_cftyperef.h"
 #include "content/common/content_export.h"
-#include "media/base/android/sdk_media_codec_bridge.h"
+#include "media/base/mac/videotoolbox_glue.h"
+#include "media/base/mac/videotoolbox_helpers.h"
 #include "media/video/video_encode_accelerator.h"
 
-namespace media {
-class BitstreamBuffer;
-}  // namespace media
-
 namespace content {
 
-// Android-specific implementation of media::VideoEncodeAccelerator, enabling
-// hardware-acceleration of video encoding, based on Android's MediaCodec class
-// (http://developer.android.com/reference/android/media/MediaCodec.html).  This
-// class expects to live and be called on a single thread (the GPU process'
-// ChildThread).
-class CONTENT_EXPORT AndroidVideoEncodeAccelerator
+// VideoToolbox.framework implementation of the VideoEncodeAccelerator
+// interface for MacOSX. VideoToolbox makes no guarantees that it is thread
+// safe, so this object is pinned to the thread on which it is constructed.
+class CONTENT_EXPORT VTVideoEncodeAccelerator
     : public media::VideoEncodeAccelerator {
  public:
-  AndroidVideoEncodeAccelerator();
-  ~AndroidVideoEncodeAccelerator() override;
+  VTVideoEncodeAccelerator();
+  ~VTVideoEncodeAccelerator() override;
 
   // media::VideoEncodeAccelerator implementation.
   media::VideoEncodeAccelerator::SupportedProfiles GetSupportedProfiles()
       override;
   bool Initialize(media::VideoPixelFormat format,
                   const gfx::Size& input_visible_size,
                   media::VideoCodecProfile output_profile,
                   uint32_t initial_bitrate,
                   Client* client) override;
   void Encode(const scoped_refptr<media::VideoFrame>& frame,
               bool force_keyframe) override;
   void UseOutputBitstreamBuffer(const media::BitstreamBuffer& buffer) override;
   void RequestEncodingParametersChange(uint32_t bitrate,
                                        uint32_t framerate) override;
   void Destroy() override;
 
  private:
-  enum {
-    // Arbitrary choice.
-    INITIAL_FRAMERATE = 30,
-    // Until there are non-realtime users, no need for unrequested I-frames.
-    IFRAME_INTERVAL = INT32_MAX,
-  };
+  using CMSampleBufferRef = CoreMediaGlue::CMSampleBufferRef;
+  using VTCompressionSessionRef = VideoToolboxGlue::VTCompressionSessionRef;
+  using VTEncodeInfoFlags = VideoToolboxGlue::VTEncodeInfoFlags;
 
-  // Impedance-mismatch fixers: MediaCodec is a poll-based API but VEA is a
-  // push-based API; these methods turn the crank to make the two work together.
-  void DoIOTask();
-  void QueueInput();
-  void DequeueOutput();
+  // Holds the associated data of a video frame being processed.
+  struct InProgressFrameEncode;
 
-  // Returns true if we don't need more or bigger output buffers.
-  bool DoOutputBuffersSuffice();
+  // Holds output buffers coming from the client ready to be filled.
+  struct BitstreamBufferRef;
 
-  // Start & stop |io_timer_| if the time seems right.
-  void MaybeStartIOTimer();
-  void MaybeStopIOTimer();
+  // Compression session callback function to handle compressed frames.
+  static void CompressionCallback(void* encoder_opaque,
+                                  void* request_opaque,
+                                  OSStatus status,
+                                  VTEncodeInfoFlags info,
+                                  CMSampleBufferRef sbuf);
+  void CompressionCallbackTask(CMSampleBufferRef sbuf);
 
-  // Used to DCHECK that we are called on the correct thread.
+  // Reset the encoder's compression session by destroying the existing one
+  // using DestroyCompressionSession() and creating a new one. The new session
+  // is configured using ConfigureCompressionSession().
+  bool ResetCompressionSession();
+
+  // Configure the current compression session using current encoder settings.
+  bool ConfigureCompressionSession();
+
+  // Destroy the current compression session if any. Blocks until all pending
+  // frames have been flushed out (similar to EmitFrames without doing any
+  // encoding work).
+  void DestroyCompressionSession();
+
+  // VideoToolboxGlue provides access to VideoToolbox at runtime.
+  const VideoToolboxGlue* videotoolbox_glue_;
+  base::ScopedCFTypeRef<VTCompressionSessionRef> compression_session_;
+
+  int32_t bitrate_;
+  gfx::Size input_visible_size_;
+
+  // Set parameters for VTCompressionSession.
+  scoped_ptr<media::video_toolbox::SessionPropertySetter>

[miu, 2016/02/09 23:29:22]

Please remove (see comment in .cc file).

+      session_property_setter_;
+
+  // Bitstream buffers ready to be used to return encoded output as a FIFO.
+  std::deque<scoped_ptr<BitstreamBufferRef>> encoder_output_queue_;
+
+  // CMSampleBufferRef needs to be copied into a BitstreamBufferRef as a FIFO.
+  std::deque<CMSampleBufferRef> encoder_output_sample_buffer_queue_;
+
+  // Our original calling task runner for the child thread.
+  const scoped_refptr<base::SingleThreadTaskRunner> client_task_runner_;
+
+  // To expose client callbacks from VideoEncodeAccelerator.
+  // NOTE: all calls to this object *MUST* be executed on
+  // |client_task_runner_|.
+  scoped_ptr<base::WeakPtrFactory<Client> > client_ptr_factory_;
+  base::WeakPtr<Client> client_;
+
+  // Thread checker to enforce that this object is used on a specific thread.
   base::ThreadChecker thread_checker_;
 
-  // VideoDecodeAccelerator::Client callbacks go here.  Invalidated once any
-  // error triggers.
-  scoped_ptr<base::WeakPtrFactory<Client> > client_ptr_factory_;
-
-  scoped_ptr<media::VideoCodecBridge> media_codec_;
-
-  // Bitstream buffers waiting to be populated & returned to the client.
-  std::vector<media::BitstreamBuffer> available_bitstream_buffers_;
-
-  // Frames waiting to be passed to the codec, queued until an input buffer is
-  // available.  Each element is a tuple of <Frame, key_frame, enqueue_time>.
-  typedef std::queue<
-      base::Tuple<scoped_refptr<media::VideoFrame>, bool, base::Time>>
-      PendingFrames;
-  PendingFrames pending_frames_;
-
-  // Repeating timer responsible for draining pending IO to the codec.
-  base::RepeatingTimer io_timer_;
-
-  // The difference between number of buffers queued & dequeued at the codec.
-  int32_t num_buffers_at_codec_;
-
-  // A monotonically-growing value, used as a fake timestamp just to keep things
-  // appearing to move forward.
-  base::TimeDelta fake_input_timestamp_;
-
-  // Number of requested output buffers and their capacity.
-  int num_output_buffers_;          // -1 until RequireBitstreamBuffers.
-  size_t output_buffers_capacity_;  // 0 until RequireBitstreamBuffers.
-
-  uint32_t last_set_bitrate_;  // In bps.
-
-  DISALLOW_COPY_AND_ASSIGN(AndroidVideoEncodeAccelerator);
+  DISALLOW_COPY_AND_ASSIGN(VTVideoEncodeAccelerator);
 };
 
-}  // namespace content
+} // namespace content
 
-#endif  // CONTENT_COMMON_GPU_MEDIA_ANDROID_VIDEO_ENCODE_ACCELERATOR_H_
+#endif  // CONTENT_COMMON_GPU_MEDIA_VT_VIDEO_ENCODE_ACCELERATOR_MAC_H_