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/*
* Copyright (c) 2018 The WebRTC project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#ifndef API_AUDIO_ECHO_CONTROL_H_
#define API_AUDIO_ECHO_CONTROL_H_
#include <memory>
#include "absl/base/nullability.h"
#include "api/environment/environment.h"
namespace webrtc {
class AudioBuffer;
// Interface for an acoustic echo cancellation (AEC) submodule.
class EchoControl {
public:
// Analysis (not changing) of the render signal.
virtual void AnalyzeRender(AudioBuffer* render) = 0;
// Analysis (not changing) of the capture signal.
virtual void AnalyzeCapture(AudioBuffer* capture) = 0;
// Processes the capture signal in order to remove the echo.
virtual void ProcessCapture(AudioBuffer* capture, bool level_change) = 0;
// As above, but also returns the linear filter output.
virtual void ProcessCapture(AudioBuffer* capture,
AudioBuffer* linear_output,
bool level_change) = 0;
struct Metrics {
double echo_return_loss;
double echo_return_loss_enhancement;
int delay_ms;
};
// Collect current metrics from the echo controller.
virtual Metrics GetMetrics() const = 0;
// Provides an optional external estimate of the audio buffer delay.
virtual void SetAudioBufferDelay(int delay_ms) = 0;
// Specifies whether the capture output will be used. The purpose of this is
// to allow the echo controller to deactivate some of the processing when the
// resulting output is anyway not used, for instance when the endpoint is
// muted.
// TODO(b/177830919): Make pure virtual.
virtual void SetCaptureOutputUsage(bool /* capture_output_used */) {}
// Returns wheter the signal is altered.
virtual bool ActiveProcessing() const = 0;
virtual ~EchoControl() {}
};
// Interface for a factory that creates EchoControllers.
class EchoControlFactory {
public:
virtual ~EchoControlFactory() = default;
virtual absl_nonnull std::unique_ptr<EchoControl> Create(
const Environment& env,
int sample_rate_hz,
int num_render_channels,
int num_capture_channels) = 0;
};
} // namespace webrtc
#endif // API_AUDIO_ECHO_CONTROL_H_
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