Add media::VideoEncodeAccelerator with WebRTC integration

content/renderer/media/rtc_video_encoder.h

+// Copyright 2013 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_RENDERER_MEDIA_RTC_VIDEO_ENCODER_H_
+#define CONTENT_RENDERER_MEDIA_RTC_VIDEO_ENCODER_H_
+
+#include <vector>
+
+#include "base/memory/ref_counted.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/memory/weak_ptr.h"
+#include "base/threading/thread_checker.h"
+#include "content/common/content_export.h"
+#include "media/base/video_decoder_config.h"
+#include "third_party/webrtc/modules/video_coding/codecs/interface/video_codec_interface.h"
+#include "ui/gfx/size.h"
+
+namespace base {
+
+class MessageLoopProxy;
+
+}  // namespace base
+
+namespace content {
+
+class RendererGpuVideoAcceleratorFactories;
+
+// This class uses a media::VideoEncodeAccelerator to implement a
+// webrtc::VideoEncoder class for WebRTC.  Internally, VEA methods are
+// trampolined to a private RTCVideoEncoder::Impl instance.  The class runs on

[Ami GONE FROM CHROMIUM, 2013/08/05 18:44:38]

"The class" is ambiguous in this sentence.

[Ami GONE FROM CHROMIUM, 2013/08/05 18:44:38]

Now that I understand that you're using Impl as a way to isolate RTCVE & Impl to
their respective threads, I love this design.
WDYT of s/Impl/ImplOnMediaThread/ to make other people come to love this design
more easily?

[sheu, 2013/08/06 06:16:36]

Done.

[sheu, 2013/08/06 06:16:36]

TBH that sounds a little excessive?  I haven't seen that convention elsewhere.

+// the |impl_message_loop_proxy_|, which is queried from the |gpu_factories_|
+// and is presently the media thread.  VEA::Client callbacks are posted back to
+// the thread that the RTCVideoEncoder constructor is called on.

[Ami GONE FROM CHROMIUM, 2013/08/05 18:44:38]

Comment could be clearer about the fact that RTCVE is created, called, and
destroyed exclusively on the libjingle worker thread.

[sheu, 2013/08/06 06:16:36]

Done.

+class CONTENT_EXPORT RTCVideoEncoder
+    : NON_EXPORTED_BASE(public webrtc::VideoEncoder) {
+ public:
+  RTCVideoEncoder(
+      media::VideoCodecProfile profile,
+      const scoped_refptr<RendererGpuVideoAcceleratorFactories>& gpu_factories);
+  virtual ~RTCVideoEncoder();
+
+  // webrtc::VideoEncoder implementation.  Tasks are posted to |impl_| using the
+  // appropriate VEA methods.
+  virtual int32_t InitEncode(const webrtc::VideoCodec* codec_settings,
+                             int32_t number_of_cores,
+                             uint32_t max_payload_size) OVERRIDE;
+  virtual int32_t Encode(
+      const webrtc::I420VideoFrame& input_image,
+      const webrtc::CodecSpecificInfo* codec_specific_info,
+      const std::vector<webrtc::VideoFrameType>* frame_types) OVERRIDE;
+  virtual int32_t RegisterEncodeCompleteCallback(
+      webrtc::EncodedImageCallback* callback) OVERRIDE;
+  virtual int32_t Release() OVERRIDE;
+  virtual int32_t SetChannelParameters(uint32_t packet_loss, int rtt) OVERRIDE;
+  virtual int32_t SetRates(uint32_t new_bit_rate, uint32_t frame_rate) OVERRIDE;
+
+ private:
+  class Impl;
+  friend class RTCVideoEncoder::Impl;
+
+  // Return an encoded output buffer to WebRTC.
+  void ReturnEncodedImage(const scoped_refptr<Impl>& impl,
+                          scoped_ptr<webrtc::EncodedImage> image,
+                          int32 bitstream_buffer_id);
+  void NotifyError(const scoped_refptr<Impl>& impl, int32_t error);

[Ami GONE FROM CHROMIUM, 2013/08/05 18:44:38]

newline

[sheu, 2013/08/06 06:16:36]

Done.

+
+  base::ThreadChecker thread_checker_;
+
+  // The video codec profile we were created with.
+  media::VideoCodecProfile video_codec_profile_;
+
+  // Factory for creating VEAs, shared memory buffers, etc.
+  scoped_refptr<RendererGpuVideoAcceleratorFactories> gpu_factories_;
+
+  // Message loop that |impl_| runs on; queried from |gpu_factories_|.

[Ami GONE FROM CHROMIUM, 2013/08/05 18:44:38]

given this is always equal to gpu_factories_->GetMessageLoop() why bother having
a local copy here?

[sheu, 2013/08/06 06:16:36]

To save some typing and ref/unrefs?

I guess I can remove it.

+  const scoped_refptr<base::MessageLoopProxy> impl_message_loop_proxy_;
+
+  // Weak pointer and factory for posting back VEA::Client notifications to
+  // RTCVideoEncoder.
+  base::WeakPtrFactory<RTCVideoEncoder> weak_this_factory_;
+  base::WeakPtr<RTCVideoEncoder> weak_this_;
+
+  // webrtc::VideoEncoder encode complete callback.
+  webrtc::EncodedImageCallback* encoded_image_callback_;
+
+  // The RTCVideoEncoder::Impl that does all the work.
+  scoped_refptr<Impl> impl_;
+
+  // We cannot immediately return error conditions to the WebRTC user of this
+  // class, as there is no error callback in the webrtc::VideoEncoder interface.
+  // Instead, we cache an error status here and return it the next time an
+  // interface entry point is called.
+  int32_t impl_status_;
+
+  DISALLOW_COPY_AND_ASSIGN(RTCVideoEncoder);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_RENDERER_MEDIA_RTC_VIDEO_ENCODER_H_