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// Copyright 2022 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef THIRD_PARTY_BLINK_RENDERER_MODULES_WEBAUDIO_MEDIA_ELEMENT_AUDIO_SOURCE_HANDLER_H_
#define THIRD_PARTY_BLINK_RENDERER_MODULES_WEBAUDIO_MEDIA_ELEMENT_AUDIO_SOURCE_HANDLER_H_
#include <memory>
#include "base/memory/scoped_refptr.h"
#include "base/notreached.h"
#include "base/task/single_thread_task_runner.h"
#include "base/thread_annotations.h"
#include "third_party/blink/renderer/bindings/core/v8/active_script_wrappable.h"
#include "third_party/blink/renderer/modules/webaudio/audio_node.h"
#include "third_party/blink/renderer/platform/audio/audio_source_provider_client.h"
#include "third_party/blink/renderer/platform/audio/media_multi_channel_resampler.h"
#include "third_party/blink/renderer/platform/heap/cross_thread_persistent.h"
namespace blink {
class AudioContext;
class HTMLMediaElement;
class MediaElementAudioSourceOptions;
class MediaElementAudioSourceHandler final : public AudioHandler {
public:
static scoped_refptr<MediaElementAudioSourceHandler> Create(
AudioNode&,
HTMLMediaElement&);
~MediaElementAudioSourceHandler() override;
CrossThreadPersistent<HTMLMediaElement> MediaElement() const;
// AudioHandler
void Dispose() override;
void Process(uint32_t frames_to_process) override;
// AudioNode
double TailTime() const override { return 0; }
double LatencyTime() const override { return 0; }
// Helpers for AudioSourceProviderClient implementation of
// MediaElementAudioSourceNode.
void SetFormat(uint32_t number_of_channels, float sample_rate);
void lock() EXCLUSIVE_LOCK_FUNCTION(GetProcessLock());
void unlock() UNLOCK_FUNCTION(GetProcessLock());
// For thread safety analysis only. Does not actually return mu.
base::Lock* GetProcessLock() LOCK_RETURNED(process_lock_) { NOTREACHED(); }
bool RequiresTailProcessing() const final { return false; }
private:
MediaElementAudioSourceHandler(AudioNode&, HTMLMediaElement&);
// As an audio source, we will never propagate silence.
bool PropagatesSilence() const override { return false; }
// Returns true if the origin of the media element is tainted so that the
// audio should be muted when playing through WebAudio.
bool WouldTaintOrigin();
// Print warning if CORS restrictions cause MediaElementAudioSource to output
// zeroes.
void PrintCorsMessage(const String& message);
// Provide input to the resampler (if used).
void ProvideResamplerInput(int resampler_frame_delay, AudioBus* dest);
// The HTMLMediaElement is held alive by MediaElementAudioSourceNode which is
// an AudioNode. AudioNode uses pre-finalizers to dispose the handler, so
// holding a weak reference is ok here and will not interfer with garbage
// collection.
//
// It is accessed by both audio and main thread. TODO: we really should
// try to minimize or avoid the audio thread touching this element.
CrossThreadWeakPersistent<HTMLMediaElement> media_element_;
base::Lock process_lock_;
unsigned source_number_of_channels_ = 0;
double source_sample_rate_ = 0;
std::unique_ptr<MediaMultiChannelResampler> multi_channel_resampler_;
scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
// True if the origin would be tainted by the media element. In this case,
// this node outputs silence. This can happen if the media element source is
// a cross-origin source which we're not allowed to access due to CORS
// restrictions.
bool is_origin_tainted_ = false;
};
} // namespace blink
#endif // THIRD_PARTY_BLINK_RENDERER_MODULES_WEBAUDIO_MEDIA_ELEMENT_AUDIO_SOURCE_HANDLER_H_
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