Implements MediaStreamVideoSource.

content/renderer/media/webrtc/webrtc_video_source.cc

+// Copyright 2013 The Chromium Authors. All rights reserved.

[Jói, 2014/01/09 11:18:13]

2014

+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "content/renderer/media/webrtc/webrtc_video_source.h"
+
+#include "content/renderer/media/media_stream_video_track.h"
+#include "third_party/libjingle/source/talk/app/webrtc/remotevideocapturer.h"
+#include "third_party/libjingle/source/talk/app/webrtc/videotrackrenderers.h"
+#include "third_party/libjingle/source/talk/media/base/videoframe.h"
+
+namespace {
+
+class FrameInputWrapper : public cricket::VideoRenderer {
+ public:
+  explicit FrameInputWrapper(cricket::VideoCapturer* capturer)
+      : capturer_(capturer) {
+    ASSERT(capturer_ != NULL);
+  }
+
+  virtual ~FrameInputWrapper() {}
+
+  // VideoRenderer implementation.
+  virtual bool SetSize(int width, int height, int reserved) OVERRIDE {
+    return true;
+  }
+
+  virtual bool RenderFrame(const cricket::VideoFrame* frame) OVERRIDE {
+    if (!capturer_->IsRunning()) {
+      return true;
+    }
+
+    // This signal will be made on media engine render thread. The clients
+    // of this signal should have no assumptions on what thread this signal
+    // come from.
+    capturer_->SignalVideoFrame(capturer_, frame);
+    return true;
+  }
+
+ private:
+  cricket::VideoCapturer* capturer_;
+  int width_;
+  int height_;
+
+  DISALLOW_COPY_AND_ASSIGN(FrameInputWrapper);
+};
+
+}  // anonymous namespace
+
+namespace content {
+
+talk_base::scoped_refptr<WebRtcVideoSource> WebRtcVideoSource::Create() {
+  talk_base::scoped_refptr<WebRtcVideoSource> source(
+      new talk_base::RefCountedObject<WebRtcVideoSource>());
+  return source;
+}
+
+WebRtcVideoSource::WebRtcVideoSource()
+    : video_capturer_(new webrtc::RemoteVideoCapturer()),
+      // TODO(ronghuawu): Rename RemoteVideoCapturer to be more general purpose.
+      // RemoteVideoCapturer is basically a fake video capturer that wraps a
+      // video frame provider as a cricket::VideoCapturer.
+      frame_input_(new FrameInputWrapper(video_capturer_.get())) {
+  video_capturer_->SignalVideoFrame.connect(
+      this,
+      &WebRtcVideoSource::OnVideoFrame);
+}
+
+WebRtcVideoSource::~WebRtcVideoSource() {
+  // Since the signal we're connecting to is multi-threaded,
+  // disconnect_all() will block until all calls are serviced, meaning any
+  // outstanding calls to OnVideoFrame will be done when this is done, and no
+  // more calls will be serviced by this.
+  // We do this explicitly instead of just letting the has_slots<> destructor
+  // take care of it because we need to do this *before* sinks_ is
+  // cleared by the destructor; otherwise we could mess with it while
+  // OnVideoFrame is running.
+  // We *don't* take sinks_crit_ here since it could deadlock with the lock
+  // taken by the video frame signal.
+  disconnect_all();
+}
+
+cricket::VideoCapturer* WebRtcVideoSource::GetVideoCapturer() {
+  return video_capturer_.get();
+}
+
+void WebRtcVideoSource::AddSink(cricket::VideoRenderer* output) {
+  if (!output) {
+      return;
+  }
+
+  talk_base::CritScope cs(&sinks_crit_);
+  sinks_.push_back(VideoSinkInfo(output));
+}
+
+void WebRtcVideoSource::RemoveSink(cricket::VideoRenderer* output) {
+  if (!output) {
+    return;
+  }
+
+  talk_base::CritScope cs(&sinks_crit_);
+  for (VideoSinks::iterator iter = sinks_.begin();
+       iter != sinks_.end(); ++iter) {
+    if (output == iter->sink) {
+      sinks_.erase(iter);
+      break;
+    }
+  }
+}
+
+const cricket::VideoOptions* WebRtcVideoSource::options() const {
+  return &options_;
+}
+
+webrtc::MediaSourceInterface::SourceState WebRtcVideoSource::state() const {
+  // TODO(ronghuawu): Implement state.
+  return state_;
+}
+
+cricket::VideoRenderer* WebRtcVideoSource::FrameInput() {
+  return frame_input_.get();
+}
+
+void WebRtcVideoSource::OnVideoFrame(cricket::VideoCapturer* capturer,
+                                     const cricket::VideoFrame* video_frame) {
+  talk_base::CritScope cs(&sinks_crit_);
+  if (sinks_.empty()) {
+    return;
+  }
+  MaybeSetSize(video_frame);
+  for (VideoSinks::iterator iter = sinks_.begin();
+       iter != sinks_.end(); ++iter) {
+    cricket::VideoRenderer* sink = iter->sink;
+    sink->RenderFrame(video_frame);
+  }
+}
+
+void WebRtcVideoSource::MaybeSetSize(const cricket::VideoFrame* frame) {
+  for (VideoSinks::iterator iter = sinks_.begin();
+       iter != sinks_.end(); ++iter) {
+    const bool new_resolution = iter->width != frame->GetWidth() ||
+        iter->height != frame->GetHeight();
+    if (new_resolution) {
+      if (iter->sink->SetSize(static_cast<int>(frame->GetWidth()),
+                              static_cast<int>(frame->GetHeight()), 0)) {
+        iter->width = frame->GetWidth();
+        iter->height = frame->GetHeight();
+      }
+    }
+  }
+}
+
+}  // namespace content