C++ MediaStream::GraphTimeToStreamTimeWithBlocking方法代码示例

void
AudioCaptureStream::ProcessInput(GraphTime aFrom, GraphTime aTo,
                                 uint32_t aFlags)
{
  uint32_t inputCount = mInputs.Length();
  StreamBuffer::Track* track = EnsureTrack(mTrackId);
  // Notify the DOM everything is in order.
  if (!mTrackCreated) {
    for (uint32_t i = 0; i < mListeners.Length(); i++) {
      MediaStreamListener* l = mListeners[i];
      AudioSegment tmp;
      l->NotifyQueuedTrackChanges(
        Graph(), mTrackId, 0, MediaStreamListener::TRACK_EVENT_CREATED, tmp);
      l->NotifyFinishedTrackCreation(Graph());
    }
    mTrackCreated = true;
  }

  // If the captured stream is connected back to a object on the page (be it an
  // HTMLMediaElement with a stream as source, or an AudioContext), a cycle
  // situation occur. This can work if it's an AudioContext with at least one
  // DelayNode, but the MSG will mute the whole cycle otherwise.
  if (mFinished || InMutedCycle() || inputCount == 0) {
    track->Get<AudioSegment>()->AppendNullData(aTo - aFrom);
  } else {
    // We mix down all the tracks of all inputs, to a stereo track. Everything
    // is {up,down}-mixed to stereo.
    mMixer.StartMixing();
    AudioSegment output;
    for (uint32_t i = 0; i < inputCount; i++) {
      MediaStream* s = mInputs[i]->GetSource();
      StreamBuffer::TrackIter tracks(s->GetStreamBuffer(), MediaSegment::AUDIO);
      while (!tracks.IsEnded()) {
        AudioSegment* inputSegment = tracks->Get<AudioSegment>();
        StreamTime inputStart = s->GraphTimeToStreamTimeWithBlocking(aFrom);
        StreamTime inputEnd = s->GraphTimeToStreamTimeWithBlocking(aTo);
        AudioSegment toMix;
        toMix.AppendSlice(*inputSegment, inputStart, inputEnd);
        // Care for streams blocked in the [aTo, aFrom] range.
        if (inputEnd - inputStart < aTo - aFrom) {
          toMix.AppendNullData((aTo - aFrom) - (inputEnd - inputStart));
        }
        toMix.Mix(mMixer, MONO, Graph()->GraphRate());
        tracks.Next();
      }
    }
    // This calls MixerCallback below
    mMixer.FinishMixing();
  }

  // Regardless of the status of the input tracks, we go foward.
  mBuffer.AdvanceKnownTracksTime(GraphTimeToStreamTimeWithBlocking((aTo)));
}

  void TrackUnionStream::CopyTrackData(StreamTracks::Track* aInputTrack,
                     uint32_t aMapIndex, GraphTime aFrom, GraphTime aTo,
                     bool* aOutputTrackFinished)
  {
    TrackMapEntry* map = &mTrackMap[aMapIndex];
    StreamTracks::Track* outputTrack = mTracks.FindTrack(map->mOutputTrackID);
    MOZ_ASSERT(outputTrack && !outputTrack->IsEnded(), "Can't copy to ended track");

    MediaSegment* segment = map->mSegment;
    MediaStream* source = map->mInputPort->GetSource();

    GraphTime next;
    *aOutputTrackFinished = false;
    for (GraphTime t = aFrom; t < aTo; t = next) {
      MediaInputPort::InputInterval interval = map->mInputPort->GetNextInputInterval(t);
      interval.mEnd = std::min(interval.mEnd, aTo);
      StreamTime inputEnd = source->GraphTimeToStreamTimeWithBlocking(interval.mEnd);
      StreamTime inputTrackEndPoint = STREAM_TIME_MAX;

      if (aInputTrack->IsEnded() &&
          aInputTrack->GetEnd() <= inputEnd) {
        inputTrackEndPoint = aInputTrack->GetEnd();
        *aOutputTrackFinished = true;
      }

      if (interval.mStart >= interval.mEnd) {
        break;
      }
      StreamTime ticks = interval.mEnd - interval.mStart;
      next = interval.mEnd;

      StreamTime outputStart = outputTrack->GetEnd();

      if (interval.mInputIsBlocked) {
        // Maybe the input track ended?
        segment->AppendNullData(ticks);
        STREAM_LOG(LogLevel::Verbose, ("TrackUnionStream %p appending %lld ticks of null data to track %d",
                   this, (long long)ticks, outputTrack->GetID()));
      } else if (InMutedCycle()) {
        segment->AppendNullData(ticks);
      } else {
        if (source->IsSuspended()) {
          segment->AppendNullData(aTo - aFrom);
        } else {
          MOZ_ASSERT(outputTrack->GetEnd() == GraphTimeToStreamTimeWithBlocking(interval.mStart),
                     "Samples missing");
          StreamTime inputStart = source->GraphTimeToStreamTimeWithBlocking(interval.mStart);
          segment->AppendSlice(*aInputTrack->GetSegment(),
                               std::min(inputTrackEndPoint, inputStart),
                               std::min(inputTrackEndPoint, inputEnd));
        }
      }
      ApplyTrackDisabling(outputTrack->GetID(), segment);
      for (uint32_t j = 0; j < mListeners.Length(); ++j) {
        MediaStreamListener* l = mListeners[j];
        // Separate Audio and Video.
        if (segment->GetType() == MediaSegment::AUDIO) {
          l->NotifyQueuedAudioData(Graph(), outputTrack->GetID(),
                                   outputStart,
                                   *static_cast<AudioSegment*>(segment),
                                   map->mInputPort->GetSource(),
                                   map->mInputTrackID);
        }
      }
      for (TrackBound<MediaStreamTrackListener>& b : mTrackListeners) {
        if (b.mTrackID != outputTrack->GetID()) {
          continue;
        }
        b.mListener->NotifyQueuedChanges(Graph(), outputStart, *segment);
      }
      outputTrack->GetSegment()->AppendFrom(segment);
    }
  }

void TrackUnionStream::CopyTrackData(StreamTracks::Track* aInputTrack,
                                     uint32_t aMapIndex, GraphTime aFrom,
                                     GraphTime aTo,
                                     bool* aOutputTrackFinished) {
  TrackMapEntry* map = &mTrackMap[aMapIndex];
  TRACE_AUDIO_CALLBACK_COMMENT(
      "Input stream %p track %i -> TrackUnionStream %p track %i",
      map->mInputPort->GetSource(), map->mInputTrackID, this,
      map->mOutputTrackID);
  StreamTracks::Track* outputTrack = mTracks.FindTrack(map->mOutputTrackID);
  MOZ_ASSERT(outputTrack && !outputTrack->IsEnded(),
             "Can't copy to ended track");

  MediaSegment* segment = map->mSegment;
  MediaStream* source = map->mInputPort->GetSource();

  GraphTime next;
  *aOutputTrackFinished = false;
  for (GraphTime t = aFrom; t < aTo; t = next) {
    MediaInputPort::InputInterval interval =
        map->mInputPort->GetNextInputInterval(t);
    interval.mEnd = std::min(interval.mEnd, aTo);
    StreamTime inputEnd =
        source->GraphTimeToStreamTimeWithBlocking(interval.mEnd);

    if (aInputTrack->IsEnded() && aInputTrack->GetEnd() <= inputEnd) {
      *aOutputTrackFinished = true;
      break;
    }

    if (interval.mStart >= interval.mEnd) {
      break;
    }
    StreamTime ticks = interval.mEnd - interval.mStart;
    next = interval.mEnd;

    StreamTime outputStart = outputTrack->GetEnd();

    if (interval.mInputIsBlocked) {
      segment->AppendNullData(ticks);
      STREAM_LOG(
          LogLevel::Verbose,
          ("TrackUnionStream %p appending %lld ticks of null data to track %d",
           this, (long long)ticks, outputTrack->GetID()));
    } else if (InMutedCycle()) {
      segment->AppendNullData(ticks);
    } else {
      if (source->IsSuspended()) {
        segment->AppendNullData(aTo - aFrom);
      } else {
        MOZ_ASSERT(outputTrack->GetEnd() ==
                       GraphTimeToStreamTimeWithBlocking(interval.mStart),
                   "Samples missing");
        StreamTime inputStart =
            source->GraphTimeToStreamTimeWithBlocking(interval.mStart);
        segment->AppendSlice(*aInputTrack->GetSegment(), inputStart, inputEnd);
      }
    }
    ApplyTrackDisabling(outputTrack->GetID(), segment);
    for (TrackBound<MediaStreamTrackListener>& b : mTrackListeners) {
      if (b.mTrackID != outputTrack->GetID()) {
        continue;
      }
      b.mListener->NotifyQueuedChanges(Graph(), outputStart, *segment);
    }
    outputTrack->GetSegment()->AppendFrom(segment);
  }
}