H264 HW encode using VideoToolbox

content/common/gpu/media/vt_video_encode_accelerator.h

+// 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_VT_VIDEO_ENCODE_ACCELERATOR_H_
+#define CONTENT_COMMON_GPU_MEDIA_VT_VIDEO_ENCODE_ACCELERATOR_H_
+
+#include "base/mac/scoped_cftyperef.h"
+#include "content/common/content_export.h"
+#include "media/base/mac/videotoolbox_glue.h"
+#include "media/video/video_encode_accelerator.h"
+
+namespace content {
+
+// VideoToolbox.framework implementation of the VideoEncodeAccelerator
+// interface for MacOSX.
+class CONTENT_EXPORT VTVideoEncodeAccelerator
+    : public media::VideoEncodeAccelerator {
+ public:
+  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;
+
+  // Holds output buffers coming from the client ready to be filled.
+  struct BitstreamBufferRef;
+
+ private:
+  typedef CoreMediaGlue::CMSampleBufferRef CMSampleBufferRef;

[mcasas, 2016/02/03 20:01:31]

using CMSampleBufferRef = CoreMediaGlue::CMSampleBufferRef;
here and in the next 2 lines.

[emircan, 2016/02/04 05:18:52]

Done.

+  typedef VideoToolboxGlue::VTCompressionSessionRef VTCompressionSessionRef;
+  typedef VideoToolboxGlue::VTEncodeInfoFlags VTEncodeInfoFlags;
+
+  // Compression session callback function to handle compressed frames.
+  static void CompressionCallback(void* encoder_opaque,
+                                  void* request_opaque,
+                                  OSStatus status,
+                                  VTEncodeInfoFlags info,
+                                  CMSampleBufferRef sbuf);
+
+  // 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.
+  void 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* const videotoolbox_glue_;
+  base::ScopedCFTypeRef<VTCompressionSessionRef> compression_session_;
+
+  // Initial parameters given by media::VideoEncodeAccelerator::Initialize()
+  uint32_t bitrate_;
+  gfx::Size input_visible_size_;
+
+  // Bitstream buffers ready to be used to return encoded output, as a LIFO
+  // since we don't care about ordering.
+  std::deque<scoped_ptr<BitstreamBufferRef>> encoder_output_queue_;
+
+  // Our original calling task runner for the child thread.
+  const scoped_refptr<base::SingleThreadTaskRunner> child_task_runner_;

[mcasas, 2016/02/03 20:01:31]

nit: s/child_task_runner_/callback_task_runner_/ ?

[emircan, 2016/02/04 05:18:52]

callback might be confusing since there are callbacks to VTSession. I will go
with client_task_runner_?

+
+  // To expose client callbacks from VideoEncodeAccelerator.
+  // NOTE: all calls to these objects *MUST* be executed on
+  // child_task_runner_.

[mcasas, 2016/02/03 20:01:31]

|child_task_runner_|

[emircan, 2016/02/04 05:18:52]

Done.

+  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_;
+
+  DISALLOW_COPY_AND_ASSIGN(VTVideoEncodeAccelerator);
+};
+
+} // namespace content
+
+#endif  // CONTENT_COMMON_GPU_MEDIA_VT_VIDEO_ENCODE_ACCELERATOR_H_