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// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef MEDIA_BASE_AUDIO_CAPTURER_SOURCE_H_
#define MEDIA_BASE_AUDIO_CAPTURER_SOURCE_H_
#include <string>
#include <vector>
#include "base/memory/ref_counted.h"
#include "media/base/audio_bus.h"
#include "media/base/audio_parameters.h"
#include "media/base/media_export.h"
namespace media {
class AudioProcessorControls;
// AudioCapturerSource is an interface representing the source for
// captured audio. An implementation will periodically call
// `CaptureCallback::Capture()` to pass the audio samples. All methods must be
// called on the same thread. The supplied `CaptureCallback` will be called on
// the same thread, except `Capture()`. Implementations should use a dedicated
// thread to receive the stream and call `CaptureCallback::Capture()` in order
// to ensure that the client receives the stream without delays.
class AudioCapturerSource
: public base::RefCountedThreadSafe<media::AudioCapturerSource> {
public:
enum class ErrorCode {
kUnknown = 0,
kSystemPermissions = 1,
kDeviceInUse = 2,
};
class CaptureCallback {
public:
// Signals that audio recording has been started. Called asynchronously
// after Start() has completed. If Start() encounters problems before this
// callback can be made, OnCaptureError will be called instead.
// This callback is provided for sources such as local audio sources that
// require asynchronous initialization so not all sources will support this
// notification.
virtual void OnCaptureStarted() {}
// Callback to deliver the captured data from the stream. Called from a
// thread that's different from the thread used for all other methods.
virtual void Capture(const AudioBus* audio_source,
base::TimeTicks audio_capture_time,
double volume,
bool key_pressed) = 0;
// Signals an error has occurred.
virtual void OnCaptureError(ErrorCode code, const std::string& message) = 0;
// Signals the muted state has changed. May be called before
// OnCaptureStarted.
virtual void OnCaptureMuted(bool is_muted) = 0;
// For streams created with audio processing, signals that a controllable
// audio processor has been created.
virtual void OnCaptureProcessorCreated(AudioProcessorControls* controls) {}
protected:
virtual ~CaptureCallback() {}
};
// Sets information about the audio stream format and the device to be used.
// It must be called exactly once before any of the other methods.
virtual void Initialize(const AudioParameters& params,
CaptureCallback* callback) = 0;
// Starts the audio recording.
virtual void Start() = 0;
// Stops the audio recording. This API is synchronous, and no more data
// callback will be passed to the client after it is being called.
virtual void Stop() = 0;
// Sets the capture volume, with range [0.0, 1.0] inclusive.
virtual void SetVolume(double volume) = 0;
// Enables or disables the WebRtc AGC control.
virtual void SetAutomaticGainControl(bool enable) = 0;
// Sets the output device the source should cancel echo from, if
// supported. Must be called on the main thread. Device ids are gotten from
// device enumerations.
virtual void SetOutputDeviceForAec(const std::string& output_device_id) = 0;
protected:
friend class base::RefCountedThreadSafe<AudioCapturerSource>;
virtual ~AudioCapturerSource() {}
};
} // namespace media
#endif // MEDIA_BASE_AUDIO_CAPTURER_SOURCE_H_
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