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// Copyright 2023 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef COMPONENTS_CAPTURE_MODE_AUDIO_CAPTURER_H_
#define COMPONENTS_CAPTURE_MODE_AUDIO_CAPTURER_H_
#include <memory>
#include <string_view>
#include "base/memory/weak_ptr.h"
#include "base/sequence_checker.h"
#include "base/time/time.h"
#include "components/capture_mode/capture_mode_export.h"
#include "media/base/audio_bus.h"
#include "media/base/audio_bus_pool.h"
#include "media/base/audio_capturer_source.h"
#include "media/base/audio_parameters.h"
#include "media/mojo/mojom/audio_stream_factory.mojom-forward.h"
#include "mojo/public/cpp/bindings/pending_remote.h"
namespace capture_mode {
// Defines the type of the callback that will be triggered repeatedly by the
// audio input device to deliver a stream of buffers containing the captured
// audio data. Each call will provide an `audio_bus` and the
// `audio_capture_time` when the first frame of that bus was captured.
// This callback will be invoked on a worker thread created by the audio input
// device (`media::AudioDeviceThread`). The provided `audio_bus` owns its own
// memory.
using OnAudioCapturedCallback =
base::RepeatingCallback<void(std::unique_ptr<media::AudioBus> audio_bus,
base::TimeTicks audio_capture_time)>;
// Defines an audio capturer that can capture an audio input device whose ID is
// `device_id`. The provided `audio_stream_factory` will be used so that the
// underlying `AudioInputDevice` can communicate with audio service via IPC. The
// provided `audio_params` will be used to initialize the underlying audio
// capturer. `callback` will be invoked according to the rules specified above.
class CAPTURE_MODE_EXPORT AudioCapturer
: public media::AudioCapturerSource::CaptureCallback {
public:
AudioCapturer(std::string_view device_id,
mojo::PendingRemote<media::mojom::AudioStreamFactory>
audio_stream_factory,
const media::AudioParameters& audio_params,
OnAudioCapturedCallback callback);
AudioCapturer(const AudioCapturer&) = delete;
AudioCapturer& operator=(const AudioCapturer&) = delete;
~AudioCapturer() override;
// Starts and stops the audio capture.
void Start();
void Stop();
// media::AudioCapturerSource::CaptureCallback:
void OnCaptureStarted() override;
void Capture(const media::AudioBus* audio_source,
base::TimeTicks audio_capture_time,
const media::AudioGlitchInfo& glitch_info,
double volume) override;
void OnCaptureError(media::AudioCapturerSource::ErrorCode code,
const std::string& message) override;
void OnCaptureMuted(bool is_muted) override;
private:
// Will be called when the audio bus that we send to the client via
// `on_audio_captured_callback_` (which in turn wraps the `backing_audio_bus`)
// is destroyed. The `backing_audio_bus` can then be inserted back into the
// `audio_bus_pool_`.
void OnAudioBusDone(std::unique_ptr<media::AudioBus> backing_audio_bus);
SEQUENCE_CHECKER(sequence_checker_);
scoped_refptr<media::AudioCapturerSource> audio_capturer_;
const OnAudioCapturedCallback on_audio_captured_callback_;
// An audio bus pool which we use to avoid allocating audio buses on the real-
// time audio thread when `Capture()` above is called.
media::AudioBusPoolImpl audio_bus_pool_;
// This will be initialized in the ctor as a weak ptr to `this`, and will be
// used to bind a callback to `OnAudioBusDone()`. The creation of this weak
// ptr, its invalidation, and the invocation of the callback bound to
// `OnAudioBusDone()` will all be done on the same sequence guarded by the
// above `sequence_checker_`.
base::WeakPtr<AudioCapturer> weak_ptr_this_;
base::WeakPtrFactory<AudioCapturer> weak_ptr_factory_{this};
};
} // namespace capture_mode
#endif // COMPONENTS_CAPTURE_MODE_AUDIO_CAPTURER_H_
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