gecko-dev/dom/media/mediasink/AudioSinkWrapper.cpp

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "AudioSinkWrapper.h"
#include "AudioSink.h"
#include "VideoUtils.h"
#include "mozilla/Result.h"
#include "nsPrintfCString.h"

namespace mozilla {

using media::TimeUnit;

AudioSinkWrapper::~AudioSinkWrapper() = default;

void AudioSinkWrapper::Shutdown() {
  AssertOwnerThread();
  MOZ_ASSERT(!mIsStarted, "Must be called after playback stopped.");
  mCreator = nullptr;
}

RefPtr<MediaSink::EndedPromise> AudioSinkWrapper::OnEnded(TrackType aType) {
  AssertOwnerThread();
  MOZ_ASSERT(mIsStarted, "Must be called after playback starts.");
  if (aType == TrackInfo::kAudioTrack) {
    return mEndedPromise;
  }
  return nullptr;
}

TimeUnit AudioSinkWrapper::GetEndTime(TrackType aType) const {
  AssertOwnerThread();
  MOZ_ASSERT(mIsStarted, "Must be called after playback starts.");
  if (aType == TrackInfo::kAudioTrack && mAudioSink) {
    return mAudioSink->GetEndTime();
  }
  return TimeUnit::Zero();
}

TimeUnit AudioSinkWrapper::GetVideoPosition(TimeStamp aNow) const {
  AssertOwnerThread();
  MOZ_ASSERT(!mPlayStartTime.IsNull());
  // Time elapsed since we started playing.
  double delta = (aNow - mPlayStartTime).ToSeconds();
  // Take playback rate into account.
  return mPlayDuration + TimeUnit::FromSeconds(delta * mParams.mPlaybackRate);
}

TimeUnit AudioSinkWrapper::GetPosition(TimeStamp* aTimeStamp) const {
  AssertOwnerThread();
  MOZ_ASSERT(mIsStarted, "Must be called after playback starts.");

  TimeUnit pos;
  TimeStamp t = TimeStamp::Now();

  if (!mAudioEnded) {
    MOZ_ASSERT(mAudioSink);
    // Rely on the audio sink to report playback position when it is not ended.
    pos = mAudioSink->GetPosition();
  } else if (!mPlayStartTime.IsNull()) {
    // Calculate playback position using system clock if we are still playing.
    pos = GetVideoPosition(t);
  } else {
    // Return how long we've played if we are not playing.
    pos = mPlayDuration;
  }

  if (aTimeStamp) {
    *aTimeStamp = t;
  }

  return pos;
}

bool AudioSinkWrapper::HasUnplayedFrames(TrackType aType) const {
  AssertOwnerThread();
  return mAudioSink ? mAudioSink->HasUnplayedFrames() : false;
}

void AudioSinkWrapper::SetVolume(double aVolume) {
  AssertOwnerThread();
  mParams.mVolume = aVolume;
  if (mAudioSink) {
    mAudioSink->SetVolume(aVolume);
  }
}

void AudioSinkWrapper::SetStreamName(const nsAString& aStreamName) {
  AssertOwnerThread();
  if (mAudioSink) {
    mAudioSink->SetStreamName(aStreamName);
  }
}

void AudioSinkWrapper::SetPlaybackRate(double aPlaybackRate) {
  AssertOwnerThread();
  if (!mAudioEnded) {
    // Pass the playback rate to the audio sink. The underlying AudioStream
    // will handle playback rate changes and report correct audio position.
    mAudioSink->SetPlaybackRate(aPlaybackRate);
  } else if (!mPlayStartTime.IsNull()) {
    // Adjust playback duration and start time when we are still playing.
    TimeStamp now = TimeStamp::Now();
    mPlayDuration = GetVideoPosition(now);
    mPlayStartTime = now;
  }
  // mParams.mPlaybackRate affects GetVideoPosition(). It should be updated
  // after the calls to GetVideoPosition();
  mParams.mPlaybackRate = aPlaybackRate;

  // Do nothing when not playing. Changes in playback rate will be taken into
  // account by GetVideoPosition().
}

void AudioSinkWrapper::SetPreservesPitch(bool aPreservesPitch) {
  AssertOwnerThread();
  mParams.mPreservesPitch = aPreservesPitch;
  if (mAudioSink) {
    mAudioSink->SetPreservesPitch(aPreservesPitch);
  }
}

void AudioSinkWrapper::SetPlaying(bool aPlaying) {
  AssertOwnerThread();

  // Resume/pause matters only when playback started.
  if (!mIsStarted) {
    return;
  }

  if (mAudioSink) {
    mAudioSink->SetPlaying(aPlaying);
  }

  if (aPlaying) {
    MOZ_ASSERT(mPlayStartTime.IsNull());
    mPlayStartTime = TimeStamp::Now();
  } else {
    // Remember how long we've played.
    mPlayDuration = GetPosition();
    // mPlayStartTime must be updated later since GetPosition()
    // depends on the value of mPlayStartTime.
    mPlayStartTime = TimeStamp();
  }
}

double AudioSinkWrapper::PlaybackRate() const {
  AssertOwnerThread();
  return mParams.mPlaybackRate;
}

nsresult AudioSinkWrapper::Start(const TimeUnit& aStartTime,
                                 const MediaInfo& aInfo) {
  AssertOwnerThread();
  MOZ_ASSERT(!mIsStarted, "playback already started.");

  mIsStarted = true;
  mPlayDuration = aStartTime;
  mPlayStartTime = TimeStamp::Now();
  mAudioEnded = IsAudioSourceEnded(aInfo);

  if (mAudioEnded) {
    // Resolve promise if we start playback at the end position of the audio.
    mEndedPromise =
        aInfo.HasAudio()
            ? MediaSink::EndedPromise::CreateAndResolve(true, __func__)
            : nullptr;
    return NS_OK;
  }

  mAudioSink.reset(mCreator->Create(aStartTime));
  Result<already_AddRefed<MediaSink::EndedPromise>, nsresult> rv =
      mAudioSink->Start(mParams);
  if (rv.isErr()) {
    mEndedPromise =
        MediaSink::EndedPromise::CreateAndReject(rv.unwrapErr(), __func__);
  } else {
    mEndedPromise = rv.unwrap();
  }

  mEndedPromise
      ->Then(mOwnerThread.get(), __func__, this,
             &AudioSinkWrapper::OnAudioEnded, &AudioSinkWrapper::OnAudioEnded)
      ->Track(mAudioSinkEndedPromise);
  return rv.isErr() ? rv.unwrapErr() : NS_OK;
}

bool AudioSinkWrapper::IsAudioSourceEnded(const MediaInfo& aInfo) const {
  // no audio or empty audio queue which won't get data anymore is equivalent to
  // audio ended
  return !aInfo.HasAudio() ||
         (mAudioQueue.IsFinished() && mAudioQueue.GetSize() == 0u);
}

void AudioSinkWrapper::Stop() {
  AssertOwnerThread();
  MOZ_ASSERT(mIsStarted, "playback not started.");

  mIsStarted = false;
  mAudioEnded = true;

  if (mAudioSink) {
    mAudioSinkEndedPromise.DisconnectIfExists();
    mAudioSink->Shutdown();
    mAudioSink = nullptr;
    mEndedPromise = nullptr;
  }
}

bool AudioSinkWrapper::IsStarted() const {
  AssertOwnerThread();
  return mIsStarted;
}

bool AudioSinkWrapper::IsPlaying() const {
  AssertOwnerThread();
  return IsStarted() && !mPlayStartTime.IsNull();
}

void AudioSinkWrapper::OnAudioEnded() {
  AssertOwnerThread();
  mAudioSinkEndedPromise.Complete();
  mPlayDuration = GetPosition();
  if (!mPlayStartTime.IsNull()) {
    mPlayStartTime = TimeStamp::Now();
  }
  mAudioEnded = true;
}

void AudioSinkWrapper::GetDebugInfo(dom::MediaSinkDebugInfo& aInfo) {
  AssertOwnerThread();
  aInfo.mAudioSinkWrapper.mIsPlaying = IsPlaying();
  aInfo.mAudioSinkWrapper.mIsStarted = IsStarted();
  aInfo.mAudioSinkWrapper.mAudioEnded = mAudioEnded;
  if (mAudioSink) {
    mAudioSink->GetDebugInfo(aInfo);
  }
}

}  // namespace mozilla