pc/video_track.cc

/*
 *  Copyright 2011 The WebRTC project authors. All Rights Reserved.
 *
 *  Use of this source code is governed by a BSD-style license
 *  that can be found in the LICENSE file in the root of the source
 *  tree. An additional intellectual property rights grant can be found
 *  in the file PATENTS.  All contributing project authors may
 *  be found in the AUTHORS file in the root of the source tree.
 */

#include "pc/video_track.h"

#include <string>
#include <utility>
#include <vector>

#include "api/notifier.h"
#include "api/sequence_checker.h"
#include "rtc_base/checks.h"
#include "rtc_base/location.h"
#include "rtc_base/ref_counted_object.h"

namespace webrtc {

VideoTrack::VideoTrack(const std::string& label,
                       VideoTrackSourceInterface* video_source,
                       rtc::Thread* worker_thread)
    : MediaStreamTrack<VideoTrackInterface>(label),
      worker_thread_(worker_thread),
      video_source_(video_source),
      content_hint_(ContentHint::kNone) {
  RTC_DCHECK_RUN_ON(&signaling_thread_);
  // Detach the thread checker for VideoSourceBaseGuarded since we'll make calls
  // to VideoSourceBaseGuarded on the worker thread, but we're currently on the
  // signaling thread.
  source_sequence_.Detach();
  video_source_->RegisterObserver(this);
}

VideoTrack::~VideoTrack() {
  RTC_DCHECK_RUN_ON(&signaling_thread_);
  video_source_->UnregisterObserver(this);
}

std::string VideoTrack::kind() const {
  return kVideoKind;
}

// AddOrUpdateSink and RemoveSink should be called on the worker
// thread.
void VideoTrack::AddOrUpdateSink(rtc::VideoSinkInterface<VideoFrame>* sink,
                                 const rtc::VideoSinkWants& wants) {
  RTC_DCHECK_RUN_ON(worker_thread_);
  VideoSourceBaseGuarded::AddOrUpdateSink(sink, wants);
  rtc::VideoSinkWants modified_wants = wants;
  modified_wants.black_frames = !enabled();
  video_source_->AddOrUpdateSink(sink, modified_wants);
}

void VideoTrack::RemoveSink(rtc::VideoSinkInterface<VideoFrame>* sink) {
  RTC_DCHECK_RUN_ON(worker_thread_);
  VideoSourceBaseGuarded::RemoveSink(sink);
  video_source_->RemoveSink(sink);
}

VideoTrackSourceInterface* VideoTrack::GetSource() const {
  // Callable from any thread.
  return video_source_.get();
}

VideoTrackInterface::ContentHint VideoTrack::content_hint() const {
  RTC_DCHECK_RUN_ON(worker_thread_);
  return content_hint_;
}

void VideoTrack::set_content_hint(ContentHint hint) {
  RTC_DCHECK_RUN_ON(worker_thread_);
  if (content_hint_ == hint)
    return;
  content_hint_ = hint;
  Notifier<VideoTrackInterface>::FireOnChanged();
}

bool VideoTrack::set_enabled(bool enable) {
  RTC_DCHECK_RUN_ON(worker_thread_);
  for (auto& sink_pair : sink_pairs()) {
    rtc::VideoSinkWants modified_wants = sink_pair.wants;
    modified_wants.black_frames = !enable;
    video_source_->AddOrUpdateSink(sink_pair.sink, modified_wants);
  }
  return MediaStreamTrack<VideoTrackInterface>::set_enabled(enable);
}

bool VideoTrack::enabled() const {
  RTC_DCHECK_RUN_ON(worker_thread_);
  return MediaStreamTrack<VideoTrackInterface>::enabled();
}

MediaStreamTrackInterface::TrackState VideoTrack::state() const {
  RTC_DCHECK_RUN_ON(worker_thread_);
  return MediaStreamTrack<VideoTrackInterface>::state();
}

void VideoTrack::OnChanged() {
  RTC_DCHECK_RUN_ON(&signaling_thread_);
  worker_thread_->Invoke<void>(
      RTC_FROM_HERE, [this, state = video_source_->state()]() {
        // TODO(tommi): Calling set_state() this way isn't ideal since we're
        // currently blocking the signaling thread and set_state() may
        // internally fire notifications via `FireOnChanged()` which may further
        // amplify the blocking effect on the signaling thread.
        rtc::Thread::ScopedDisallowBlockingCalls no_blocking_calls;
        set_state(state == MediaSourceInterface::kEnded ? kEnded : kLive);
      });
}

rtc::scoped_refptr<VideoTrack> VideoTrack::Create(
    const std::string& id,
    VideoTrackSourceInterface* source,
    rtc::Thread* worker_thread) {
  return rtc::make_ref_counted<VideoTrack>(id, source, worker_thread);
}

}  // namespace webrtc