Implement WebRTC in Chrome for TV

content/renderer/media/rtc_video_decoder_bridge_tv.cc

+// Copyright (c) 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.
+
+#include "content/renderer/media/rtc_video_decoder_bridge_tv.h"
+
+#include <queue>
+
+#include "base/bind.h"
+#include "base/callback_helpers.h"
+#include "base/location.h"
+#include "base/logging.h"
+#include "base/memory/ref_counted.h"
+#include "base/memory/singleton.h"
+#include "base/message_loop_proxy.h"
+#include "base/time.h"
+#include "content/renderer/media/rtc_video_decoder_factory_tv.h"
+#include "media/base/bind_to_loop.h"
+#include "media/base/decoder_buffer.h"
+#include "third_party/libjingle/source/talk/base/ratetracker.h"
+
+namespace content {
+
+RTCVideoDecoderBridgeTv::RTCVideoDecoderBridgeTv(
+    RTCVideoDecoderFactoryTv* factory)
+    : factory_(factory),
+      is_initialized_(false),
+      first_frame_(true),
+      decode_complete_callback_(NULL) {}
+
+RTCVideoDecoderBridgeTv::~RTCVideoDecoderBridgeTv() {}
+
+int32_t RTCVideoDecoderBridgeTv::InitDecode(
+    const webrtc::VideoCodec* codec_settings,
+    int32_t number_of_cores) {
+  // We don't support non-VP8 codec, feedback mode, nor double-initialization
+  if (codec_settings->codecType != webrtc::kVideoCodecVP8 ||
+      codec_settings->codecSpecific.VP8.feedbackModeOn || is_initialized_)
+    return WEBRTC_VIDEO_CODEC_ERROR;
+  size_ = gfx::Size(codec_settings->width, codec_settings->height);
+
+  is_initialized_ = true;
+  first_frame_ = true;
+  factory_->InitializeStream(size_);
+
+  return WEBRTC_VIDEO_CODEC_OK;
+}
+
+int32_t RTCVideoDecoderBridgeTv::Decode(
+    const webrtc::EncodedImage& input_image,
+    bool missing_frames,
+    const webrtc::RTPFragmentationHeader* fragmentation,
+    const webrtc::CodecSpecificInfo* codec_specific_info,
+    int64_t render_time_ms) {
+  // Unlike the SW decoder in libvpx, hw decoder can not handle broken frames.
+  // Here, we return an error in order to request a key frame.
+  if (missing_frames || !input_image._completeFrame)
+    return WEBRTC_VIDEO_CODEC_ERROR;
+
+  if (!is_initialized_ || decode_complete_callback_ == NULL)
+    return WEBRTC_VIDEO_CODEC_UNINITIALIZED;
+
+  if (first_frame_) {
+    // If the first frame is not a key frame, return an error to request a key
+    // frame.
+    if (input_image._frameType != webrtc::kKeyFrame)
+      return WEBRTC_VIDEO_CODEC_ERROR;
+
+    // Google TV expects timestamp from 0, so we store the initial timestamp as
+    // an offset and subtract the value from every timestamps to meet the
+    // expectation.
+    timestamp_offset_millis_ = render_time_ms;
+  }
+  first_frame_ = false;
+  gfx::Size new_size;
+  if (input_image._frameType == webrtc::kKeyFrame &&
+      input_image._encodedWidth != 0 && input_image._encodedHeight != 0) {
+    // Only a key frame has a meaningful size.
+    new_size.SetSize(input_image._encodedWidth, input_image._encodedHeight);
+    if (size_ == new_size)
+      new_size = gfx::Size();
+    else
+      size_ = new_size;
+  }
+  // |input_image_| may be destroyed after this call, so we make a copy of the
+  // buffer so that we can queue the buffer asynchronously.
+  scoped_refptr<media::DecoderBuffer> buffer =
+      media::DecoderBuffer::CopyFrom(input_image._buffer, input_image._length);
+  if (render_time_ms != -1) {

[acolwell GONE FROM CHROMIUM, 2013/05/20 21:23:22]

What is supposed to happen when render_time_ms == -1? Why is it ok to queue a
buffer w/o a proper timestamp set?

[wonsik, 2013/05/21 10:09:29]

Timestamp serves as a cue only, so I think it's fine.

+    buffer->SetTimestamp(base::TimeDelta::FromMilliseconds(
+        render_time_ms - timestamp_offset_millis_));
+  }
+
+  factory_->QueueBuffer(
+      buffer,
+      base::Bind(&RTCVideoDecoderBridgeTv::RunDecodeCompleteCallback,
+                 decode_complete_callback_,
+                 input_image._timeStamp),
+      new_size);
+
+  return WEBRTC_VIDEO_CODEC_OK;
+}
+
+int32_t RTCVideoDecoderBridgeTv::RegisterDecodeCompleteCallback(
+    webrtc::DecodedImageCallback* callback) {
+  decode_complete_callback_ = callback;
+  return WEBRTC_VIDEO_CODEC_OK;
+}
+
+int32_t RTCVideoDecoderBridgeTv::Release() {
+  is_initialized_ = false;
+  return WEBRTC_VIDEO_CODEC_OK;
+}
+
+int32_t RTCVideoDecoderBridgeTv::Reset() {
+  first_frame_ = true;
+  return WEBRTC_VIDEO_CODEC_OK;
+}
+
+// static
+void RTCVideoDecoderBridgeTv::RunDecodeCompleteCallback(
+    webrtc::DecodedImageCallback* callback,
+    int64_t timestamp) {
+  // We call the decode complete callback function to notify libjingle that
+  // decoding is finished. In addition, this also reports back to libjingle that
+  // the particular video frame with |timestamp| is correctly rendered to
+  // libjingle, so that it can generate proper stats.
+  webrtc::I420VideoFrame dummy_video_frame;
+  // Smallest possible non-zero I420 image is 2x2 square, with stride_y being 2
+  // and stride_u & stride_v being 1. In other words, this dummy frame contains
+  // 2x2 y values and 1x1 u & v values each.
+  dummy_video_frame.CreateEmptyFrame(2, 2, 2, 1, 1);
+  dummy_video_frame.set_timestamp(timestamp);
+  callback->Decoded(dummy_video_frame);
+}
+
+}  // namespace content