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Diffstat (limited to 'dom/media/webaudio/AudioDestinationNode.cpp')
| -rw-r--r-- | dom/media/webaudio/AudioDestinationNode.cpp | 675 |
1 files changed, 675 insertions, 0 deletions
diff --git a/dom/media/webaudio/AudioDestinationNode.cpp b/dom/media/webaudio/AudioDestinationNode.cpp new file mode 100644 index 0000000000..a40e3b5eea --- /dev/null +++ b/dom/media/webaudio/AudioDestinationNode.cpp @@ -0,0 +1,675 @@ +/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ +/* vim:set ts=2 sw=2 sts=2 et cindent: */ +/* 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 "AudioDestinationNode.h" + +#include "AlignmentUtils.h" +#include "AudibilityMonitor.h" +#include "AudioChannelService.h" +#include "AudioContext.h" +#include "AudioNodeEngine.h" +#include "AudioNodeTrack.h" +#include "CubebUtils.h" +#include "MediaTrackGraph.h" +#include "mozilla/StaticPrefs_dom.h" +#include "mozilla/dom/AudioDestinationNodeBinding.h" +#include "mozilla/dom/BaseAudioContextBinding.h" +#include "mozilla/dom/OfflineAudioCompletionEvent.h" +#include "mozilla/dom/Promise.h" +#include "mozilla/dom/ScriptSettings.h" +#include "mozilla/dom/WakeLock.h" +#include "mozilla/dom/power/PowerManagerService.h" +#include "mozilla/Telemetry.h" +#include "mozilla/TelemetryHistogramEnums.h" +#include "nsContentUtils.h" +#include "nsIInterfaceRequestorUtils.h" +#include "nsIScriptObjectPrincipal.h" +#include "nsServiceManagerUtils.h" +#include "Tracing.h" + +extern mozilla::LazyLogModule gAudioChannelLog; + +#define AUDIO_CHANNEL_LOG(msg, ...) \ + MOZ_LOG(gAudioChannelLog, LogLevel::Debug, (msg, ##__VA_ARGS__)) + +namespace mozilla::dom { + +namespace { +class OnCompleteTask final : public Runnable { + public: + OnCompleteTask(AudioContext* aAudioContext, AudioBuffer* aRenderedBuffer) + : Runnable("dom::OfflineDestinationNodeEngine::OnCompleteTask"), + mAudioContext(aAudioContext), + mRenderedBuffer(aRenderedBuffer) {} + + NS_IMETHOD Run() override { + OfflineAudioCompletionEventInit param; + param.mRenderedBuffer = mRenderedBuffer; + + RefPtr<OfflineAudioCompletionEvent> event = + OfflineAudioCompletionEvent::Constructor(mAudioContext, u"complete"_ns, + param); + mAudioContext->DispatchTrustedEvent(event); + + return NS_OK; + } + + private: + RefPtr<AudioContext> mAudioContext; + RefPtr<AudioBuffer> mRenderedBuffer; +}; +} // anonymous namespace + +class OfflineDestinationNodeEngine final : public AudioNodeEngine { + public: + explicit OfflineDestinationNodeEngine(AudioDestinationNode* aNode) + : AudioNodeEngine(aNode), + mWriteIndex(0), + mNumberOfChannels(aNode->ChannelCount()), + mLength(aNode->Length()), + mSampleRate(aNode->Context()->SampleRate()), + mBufferAllocated(false) {} + + void ProcessBlock(AudioNodeTrack* aTrack, GraphTime aFrom, + const AudioBlock& aInput, AudioBlock* aOutput, + bool* aFinished) override { + TRACE("OfflineDestinationNodeEngine::ProcessBlock"); + // Do this just for the sake of political correctness; this output + // will not go anywhere. + *aOutput = aInput; + + // The output buffer is allocated lazily, on the rendering thread, when + // non-null input is received. + if (!mBufferAllocated && !aInput.IsNull()) { + // These allocations might fail if content provides a huge number of + // channels or size, but it's OK since we'll deal with the failure + // gracefully. + mBuffer = ThreadSharedFloatArrayBufferList::Create(mNumberOfChannels, + mLength, fallible); + if (mBuffer && mWriteIndex) { + // Zero leading for any null chunks that were skipped. + for (uint32_t i = 0; i < mNumberOfChannels; ++i) { + float* channelData = mBuffer->GetDataForWrite(i); + PodZero(channelData, mWriteIndex); + } + } + + mBufferAllocated = true; + } + + // Skip copying if there is no buffer. + uint32_t outputChannelCount = mBuffer ? mNumberOfChannels : 0; + + // Record our input buffer + MOZ_ASSERT(mWriteIndex < mLength, "How did this happen?"); + const uint32_t duration = + std::min(WEBAUDIO_BLOCK_SIZE, mLength - mWriteIndex); + const uint32_t inputChannelCount = aInput.ChannelCount(); + for (uint32_t i = 0; i < outputChannelCount; ++i) { + float* outputData = mBuffer->GetDataForWrite(i) + mWriteIndex; + if (aInput.IsNull() || i >= inputChannelCount) { + PodZero(outputData, duration); + } else { + const float* inputBuffer = + static_cast<const float*>(aInput.mChannelData[i]); + if (duration == WEBAUDIO_BLOCK_SIZE && IS_ALIGNED16(inputBuffer)) { + // Use the optimized version of the copy with scale operation + AudioBlockCopyChannelWithScale(inputBuffer, aInput.mVolume, + outputData); + } else { + if (aInput.mVolume == 1.0f) { + PodCopy(outputData, inputBuffer, duration); + } else { + for (uint32_t j = 0; j < duration; ++j) { + outputData[j] = aInput.mVolume * inputBuffer[j]; + } + } + } + } + } + mWriteIndex += duration; + + if (mWriteIndex >= mLength) { + NS_ASSERTION(mWriteIndex == mLength, "Overshot length"); + // Go to finished state. When the graph's current time eventually reaches + // the end of the track, then the main thread will be notified and we'll + // shut down the AudioContext. + *aFinished = true; + } + } + + bool IsActive() const override { + // Keep processing to track track time, which is used for all timelines + // associated with the same AudioContext. + return true; + } + + already_AddRefed<AudioBuffer> CreateAudioBuffer(AudioContext* aContext) { + MOZ_ASSERT(NS_IsMainThread()); + // Create the input buffer + ErrorResult rv; + RefPtr<AudioBuffer> renderedBuffer = + AudioBuffer::Create(aContext->GetOwner(), mNumberOfChannels, mLength, + mSampleRate, mBuffer.forget(), rv); + if (rv.Failed()) { + rv.SuppressException(); + return nullptr; + } + + return renderedBuffer.forget(); + } + + size_t SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const override { + size_t amount = AudioNodeEngine::SizeOfExcludingThis(aMallocSizeOf); + if (mBuffer) { + amount += mBuffer->SizeOfIncludingThis(aMallocSizeOf); + } + return amount; + } + + size_t SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) const override { + return aMallocSizeOf(this) + SizeOfExcludingThis(aMallocSizeOf); + } + + private: + // The input to the destination node is recorded in mBuffer. + // When this buffer fills up with mLength frames, the buffered input is sent + // to the main thread in order to dispatch OfflineAudioCompletionEvent. + RefPtr<ThreadSharedFloatArrayBufferList> mBuffer; + // An index representing the next offset in mBuffer to be written to. + uint32_t mWriteIndex; + uint32_t mNumberOfChannels; + // How many frames the OfflineAudioContext intends to produce. + uint32_t mLength; + float mSampleRate; + bool mBufferAllocated; +}; + +class DestinationNodeEngine final : public AudioNodeEngine { + public: + explicit DestinationNodeEngine(AudioDestinationNode* aNode) + : AudioNodeEngine(aNode), + mSampleRate(CubebUtils::PreferredSampleRate( + aNode->Context()->ShouldResistFingerprinting())), + mVolume(1.0f), + mAudibilityMonitor( + mSampleRate, + StaticPrefs::dom_media_silence_duration_for_audibility()), + mSuspended(false), + mIsAudible(false) { + MOZ_ASSERT(aNode); + } + + void ProcessBlock(AudioNodeTrack* aTrack, GraphTime aFrom, + const AudioBlock& aInput, AudioBlock* aOutput, + bool* aFinished) override { + TRACE("DestinationNodeEngine::ProcessBlock"); + *aOutput = aInput; + aOutput->mVolume *= mVolume; + + if (mSuspended) { + return; + } + + mAudibilityMonitor.Process(aInput); + bool isAudible = + mAudibilityMonitor.RecentlyAudible() && aOutput->mVolume > 0.0; + if (isAudible != mIsAudible) { + mIsAudible = isAudible; + RefPtr<AudioNodeTrack> track = aTrack; + auto r = [track, isAudible]() -> void { + MOZ_ASSERT(NS_IsMainThread()); + RefPtr<AudioNode> node = track->Engine()->NodeMainThread(); + if (node) { + RefPtr<AudioDestinationNode> destinationNode = + static_cast<AudioDestinationNode*>(node.get()); + destinationNode->NotifyDataAudibleStateChanged(isAudible); + } + }; + + aTrack->Graph()->DispatchToMainThreadStableState(NS_NewRunnableFunction( + "dom::WebAudioAudibleStateChangedRunnable", r)); + } + } + + bool IsActive() const override { + // Keep processing to track track time, which is used for all timelines + // associated with the same AudioContext. If there are no other engines + // for the AudioContext, then this could return false to suspend the + // track, but the track is blocked anyway through + // AudioDestinationNode::SetIsOnlyNodeForContext(). + return true; + } + + void SetDoubleParameter(uint32_t aIndex, double aParam) override { + if (aIndex == VOLUME) { + mVolume = static_cast<float>(aParam); + } + } + + void SetInt32Parameter(uint32_t aIndex, int32_t aParam) override { + if (aIndex == SUSPENDED) { + mSuspended = !!aParam; + if (mSuspended) { + mIsAudible = false; + } + } + } + + enum Parameters { + VOLUME, + SUSPENDED, + }; + + size_t SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) const override { + return aMallocSizeOf(this) + SizeOfExcludingThis(aMallocSizeOf); + } + + private: + int mSampleRate; + float mVolume; + AudibilityMonitor mAudibilityMonitor; + bool mSuspended; + bool mIsAudible; +}; + +NS_IMPL_CYCLE_COLLECTION_INHERITED(AudioDestinationNode, AudioNode, + mAudioChannelAgent, mOfflineRenderingPromise) + +NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(AudioDestinationNode) + NS_INTERFACE_MAP_ENTRY(nsIAudioChannelAgentCallback) +NS_INTERFACE_MAP_END_INHERITING(AudioNode) + +NS_IMPL_ADDREF_INHERITED(AudioDestinationNode, AudioNode) +NS_IMPL_RELEASE_INHERITED(AudioDestinationNode, AudioNode) + +const AudioNodeTrack::Flags kTrackFlags = + AudioNodeTrack::NEED_MAIN_THREAD_CURRENT_TIME | + AudioNodeTrack::NEED_MAIN_THREAD_ENDED | AudioNodeTrack::EXTERNAL_OUTPUT; + +AudioDestinationNode::AudioDestinationNode(AudioContext* aContext, + bool aIsOffline, + uint32_t aNumberOfChannels, + uint32_t aLength) + : AudioNode(aContext, aNumberOfChannels, ChannelCountMode::Explicit, + ChannelInterpretation::Speakers), + mFramesToProduce(aLength), + mIsOffline(aIsOffline), + mCreatedTime(TimeStamp::Now()) { + if (aIsOffline) { + // The track is created on demand to avoid creating a graph thread that + // may not be used. + return; + } + + // GetParentObject can return nullptr here. This will end up creating another + // MediaTrackGraph + MediaTrackGraph* graph = MediaTrackGraph::GetInstance( + MediaTrackGraph::AUDIO_THREAD_DRIVER, aContext->GetParentObject(), + aContext->SampleRate(), MediaTrackGraph::DEFAULT_OUTPUT_DEVICE); + AudioNodeEngine* engine = new DestinationNodeEngine(this); + + mTrack = AudioNodeTrack::Create(aContext, engine, kTrackFlags, graph); + mTrack->AddMainThreadListener(this); + // null key is fine: only one output per mTrack + mTrack->AddAudioOutput(nullptr); +} + +void AudioDestinationNode::Init() { + // The reason we don't do that in ctor is because we have to keep AudioContext + // holding a strong reference to the destination node first. If we don't do + // that, initializing the agent would cause an unexpected destroy of the + // destination node when destroying the local weak reference inside + // `InitWithWeakCallback()`. + if (!mIsOffline) { + CreateAndStartAudioChannelAgent(); + } +} + +void AudioDestinationNode::Close() { + DestroyAudioChannelAgentIfExists(); + ReleaseAudioWakeLockIfExists(); +} + +void AudioDestinationNode::CreateAndStartAudioChannelAgent() { + MOZ_ASSERT(!mIsOffline); + MOZ_ASSERT(!mAudioChannelAgent); + + AudioChannelAgent* agent = new AudioChannelAgent(); + nsresult rv = agent->InitWithWeakCallback(GetOwner(), this); + if (NS_WARN_IF(NS_FAILED(rv))) { + AUDIO_CHANNEL_LOG("Failed to init audio channel agent"); + return; + } + + AudibleState state = + IsAudible() ? AudibleState::eAudible : AudibleState::eNotAudible; + rv = agent->NotifyStartedPlaying(state); + if (NS_WARN_IF(NS_FAILED(rv))) { + AUDIO_CHANNEL_LOG("Failed to start audio channel agent"); + return; + } + + mAudioChannelAgent = agent; + mAudioChannelAgent->PullInitialUpdate(); +} + +AudioDestinationNode::~AudioDestinationNode() { + MOZ_ASSERT(!mAudioChannelAgent); + MOZ_ASSERT(!mWakeLock); + MOZ_ASSERT(!mCaptureTrackPort); +} + +size_t AudioDestinationNode::SizeOfExcludingThis( + MallocSizeOf aMallocSizeOf) const { + size_t amount = AudioNode::SizeOfExcludingThis(aMallocSizeOf); + // Might be useful in the future: + // - mAudioChannelAgent + return amount; +} + +size_t AudioDestinationNode::SizeOfIncludingThis( + MallocSizeOf aMallocSizeOf) const { + return aMallocSizeOf(this) + SizeOfExcludingThis(aMallocSizeOf); +} + +AudioNodeTrack* AudioDestinationNode::Track() { + if (mTrack) { + return mTrack; + } + + AudioContext* context = Context(); + if (!context) { // This node has been unlinked. + return nullptr; + } + + MOZ_ASSERT(mIsOffline, "Realtime tracks are created in constructor"); + + // GetParentObject can return nullptr here when the document has been + // unlinked. + MediaTrackGraph* graph = MediaTrackGraph::CreateNonRealtimeInstance( + context->SampleRate(), context->GetParentObject()); + AudioNodeEngine* engine = new OfflineDestinationNodeEngine(this); + + mTrack = AudioNodeTrack::Create(context, engine, kTrackFlags, graph); + mTrack->AddMainThreadListener(this); + + return mTrack; +} + +void AudioDestinationNode::DestroyAudioChannelAgentIfExists() { + if (mAudioChannelAgent) { + mAudioChannelAgent->NotifyStoppedPlaying(); + mAudioChannelAgent = nullptr; + if (IsCapturingAudio()) { + StopAudioCapturingTrack(); + } + } +} + +void AudioDestinationNode::DestroyMediaTrack() { + Close(); + if (!mTrack) { + return; + } + + Context()->ShutdownWorklet(); + + mTrack->RemoveMainThreadListener(this); + AudioNode::DestroyMediaTrack(); +} + +void AudioDestinationNode::NotifyMainThreadTrackEnded() { + MOZ_ASSERT(NS_IsMainThread()); + MOZ_ASSERT(mTrack->IsEnded()); + + if (mIsOffline && GetAbstractMainThread()) { + GetAbstractMainThread()->Dispatch(NewRunnableMethod( + "dom::AudioDestinationNode::FireOfflineCompletionEvent", this, + &AudioDestinationNode::FireOfflineCompletionEvent)); + } +} + +void AudioDestinationNode::FireOfflineCompletionEvent() { + AudioContext* context = Context(); + context->OfflineClose(); + + OfflineDestinationNodeEngine* engine = + static_cast<OfflineDestinationNodeEngine*>(Track()->Engine()); + RefPtr<AudioBuffer> renderedBuffer = engine->CreateAudioBuffer(context); + if (!renderedBuffer) { + return; + } + ResolvePromise(renderedBuffer); + + context->Dispatch(do_AddRef(new OnCompleteTask(context, renderedBuffer))); + + context->OnStateChanged(nullptr, AudioContextState::Closed); + + mOfflineRenderingRef.Drop(this); +} + +void AudioDestinationNode::ResolvePromise(AudioBuffer* aRenderedBuffer) { + MOZ_ASSERT(NS_IsMainThread()); + MOZ_ASSERT(mIsOffline); + mOfflineRenderingPromise->MaybeResolve(aRenderedBuffer); +} + +uint32_t AudioDestinationNode::MaxChannelCount() const { + return Context()->MaxChannelCount(); +} + +void AudioDestinationNode::SetChannelCount(uint32_t aChannelCount, + ErrorResult& aRv) { + if (aChannelCount > MaxChannelCount()) { + aRv.ThrowIndexSizeError( + nsPrintfCString("%u is larger than maxChannelCount", aChannelCount)); + return; + } + + if (aChannelCount == ChannelCount()) { + return; + } + + AudioNode::SetChannelCount(aChannelCount, aRv); +} + +void AudioDestinationNode::Mute() { + MOZ_ASSERT(Context() && !Context()->IsOffline()); + SendDoubleParameterToTrack(DestinationNodeEngine::VOLUME, 0.0f); +} + +void AudioDestinationNode::Unmute() { + MOZ_ASSERT(Context() && !Context()->IsOffline()); + SendDoubleParameterToTrack(DestinationNodeEngine::VOLUME, 1.0f); +} + +void AudioDestinationNode::Suspend() { + SendInt32ParameterToTrack(DestinationNodeEngine::SUSPENDED, 1); +} + +void AudioDestinationNode::Resume() { + SendInt32ParameterToTrack(DestinationNodeEngine::SUSPENDED, 0); +} + +void AudioDestinationNode::NotifyAudioContextStateChanged() { + UpdateFinalAudibleStateIfNeeded(AudibleChangedReasons::ePauseStateChanged); +} + +void AudioDestinationNode::OfflineShutdown() { + MOZ_ASSERT(Context() && Context()->IsOffline(), + "Should only be called on a valid OfflineAudioContext"); + + mOfflineRenderingRef.Drop(this); +} + +JSObject* AudioDestinationNode::WrapObject(JSContext* aCx, + JS::Handle<JSObject*> aGivenProto) { + return AudioDestinationNode_Binding::Wrap(aCx, this, aGivenProto); +} + +void AudioDestinationNode::StartRendering(Promise* aPromise) { + mOfflineRenderingPromise = aPromise; + mOfflineRenderingRef.Take(this); + Track()->Graph()->StartNonRealtimeProcessing(mFramesToProduce); +} + +NS_IMETHODIMP +AudioDestinationNode::WindowVolumeChanged(float aVolume, bool aMuted) { + MOZ_ASSERT(mAudioChannelAgent); + if (!mTrack) { + return NS_OK; + } + + AUDIO_CHANNEL_LOG( + "AudioDestinationNode %p WindowVolumeChanged, " + "aVolume = %f, aMuted = %s\n", + this, aVolume, aMuted ? "true" : "false"); + + mAudioChannelVolume = aMuted ? 0.0f : aVolume; + mTrack->SetAudioOutputVolume(nullptr, mAudioChannelVolume); + UpdateFinalAudibleStateIfNeeded(AudibleChangedReasons::eVolumeChanged); + return NS_OK; +} + +NS_IMETHODIMP +AudioDestinationNode::WindowSuspendChanged(nsSuspendedTypes aSuspend) { + MOZ_ASSERT(mAudioChannelAgent); + if (!mTrack) { + return NS_OK; + } + + const bool shouldDisable = aSuspend == nsISuspendedTypes::SUSPENDED_BLOCK; + if (mAudioChannelDisabled == shouldDisable) { + return NS_OK; + } + mAudioChannelDisabled = shouldDisable; + + AUDIO_CHANNEL_LOG( + "AudioDestinationNode %p WindowSuspendChanged, shouldDisable = %d\n", + this, mAudioChannelDisabled); + + DisabledTrackMode disabledMode = mAudioChannelDisabled + ? DisabledTrackMode::SILENCE_BLACK + : DisabledTrackMode::ENABLED; + mTrack->SetDisabledTrackMode(disabledMode); + UpdateFinalAudibleStateIfNeeded(AudibleChangedReasons::ePauseStateChanged); + return NS_OK; +} + +NS_IMETHODIMP +AudioDestinationNode::WindowAudioCaptureChanged(bool aCapture) { + MOZ_ASSERT(mAudioChannelAgent); + if (!mTrack) { + return NS_OK; + } + + nsCOMPtr<nsPIDOMWindowInner> ownerWindow = GetOwner(); + if (!ownerWindow) { + return NS_OK; + } + + if (aCapture == IsCapturingAudio()) { + return NS_OK; + } + + if (aCapture) { + StartAudioCapturingTrack(); + } else { + StopAudioCapturingTrack(); + } + + return NS_OK; +} + +bool AudioDestinationNode::IsCapturingAudio() const { + return mCaptureTrackPort != nullptr; +} + +void AudioDestinationNode::StartAudioCapturingTrack() { + MOZ_ASSERT(!IsCapturingAudio()); + nsCOMPtr<nsPIDOMWindowInner> window = Context()->GetParentObject(); + uint64_t id = window->WindowID(); + mCaptureTrackPort = mTrack->Graph()->ConnectToCaptureTrack(id, mTrack); +} + +void AudioDestinationNode::StopAudioCapturingTrack() { + MOZ_ASSERT(IsCapturingAudio()); + mCaptureTrackPort->Destroy(); + mCaptureTrackPort = nullptr; +} + +void AudioDestinationNode::CreateAudioWakeLockIfNeeded() { + if (!mWakeLock && IsAudible()) { + RefPtr<power::PowerManagerService> pmService = + power::PowerManagerService::GetInstance(); + NS_ENSURE_TRUE_VOID(pmService); + + ErrorResult rv; + mWakeLock = pmService->NewWakeLock(u"audio-playing"_ns, GetOwner(), rv); + } +} + +void AudioDestinationNode::ReleaseAudioWakeLockIfExists() { + if (mWakeLock) { + IgnoredErrorResult rv; + mWakeLock->Unlock(rv); + mWakeLock = nullptr; + } +} + +void AudioDestinationNode::NotifyDataAudibleStateChanged(bool aAudible) { + MOZ_ASSERT(!mIsOffline); + + AUDIO_CHANNEL_LOG( + "AudioDestinationNode %p NotifyDataAudibleStateChanged, audible=%d", this, + aAudible); + + if (mDurationBeforeFirstTimeAudible.IsZero()) { + MOZ_ASSERT(aAudible); + mDurationBeforeFirstTimeAudible = TimeStamp::Now() - mCreatedTime; + Telemetry::Accumulate(Telemetry::WEB_AUDIO_BECOMES_AUDIBLE_TIME, + mDurationBeforeFirstTimeAudible.ToSeconds()); + } + + mIsDataAudible = aAudible; + UpdateFinalAudibleStateIfNeeded(AudibleChangedReasons::eDataAudibleChanged); +} + +void AudioDestinationNode::UpdateFinalAudibleStateIfNeeded( + AudibleChangedReasons aReason) { + // The audio context has been closed and we've destroyed the agent. + if (!mAudioChannelAgent) { + return; + } + const bool newAudibleState = IsAudible(); + if (mFinalAudibleState == newAudibleState) { + return; + } + AUDIO_CHANNEL_LOG("AudioDestinationNode %p Final audible state=%d", this, + newAudibleState); + mFinalAudibleState = newAudibleState; + AudibleState state = + mFinalAudibleState ? AudibleState::eAudible : AudibleState::eNotAudible; + mAudioChannelAgent->NotifyStartedAudible(state, aReason); + if (mFinalAudibleState) { + CreateAudioWakeLockIfNeeded(); + } else { + ReleaseAudioWakeLockIfExists(); + } +} + +bool AudioDestinationNode::IsAudible() const { + // The desitionation node will be regarded as audible if all following + // conditions are true. + // (1) data audible state : both audio input and output are audible + // (2) window audible state : the tab isn't muted by tab sound indicator + // (3) audio context state : audio context should be running + return Context()->State() == AudioContextState::Running && mIsDataAudible && + mAudioChannelVolume != 0.0; +} + +} // namespace mozilla::dom |