1 /* 2 * Copyright (c) 2018 The WebRTC project authors. All Rights Reserved. 3 * 4 * Use of this source code is governed by a BSD-style license 5 * that can be found in the LICENSE file in the root of the source 6 * tree. An additional intellectual property rights grant can be found 7 * in the file PATENTS. All contributing project authors may 8 * be found in the AUTHORS file in the root of the source tree. 9 */ 10 11 #ifndef API_AUDIO_ECHO_CONTROL_H_ 12 #define API_AUDIO_ECHO_CONTROL_H_ 13 14 #include <memory> 15 16 #include "rtc_base/checks.h" 17 18 namespace webrtc { 19 20 class AudioBuffer; 21 22 // Interface for an acoustic echo cancellation (AEC) submodule. 23 class EchoControl { 24 public: 25 // Analysis (not changing) of the render signal. 26 virtual void AnalyzeRender(AudioBuffer* render) = 0; 27 28 // Analysis (not changing) of the capture signal. 29 virtual void AnalyzeCapture(AudioBuffer* capture) = 0; 30 31 // Processes the capture signal in order to remove the echo. 32 virtual void ProcessCapture(AudioBuffer* capture, bool level_change) = 0; 33 34 // As above, but also returns the linear filter output. 35 virtual void ProcessCapture(AudioBuffer* capture, 36 AudioBuffer* linear_output, 37 bool level_change) = 0; 38 39 struct Metrics { 40 double echo_return_loss; 41 double echo_return_loss_enhancement; 42 int delay_ms; 43 }; 44 45 // Collect current metrics from the echo controller. 46 virtual Metrics GetMetrics() const = 0; 47 48 // Provides an optional external estimate of the audio buffer delay. 49 virtual void SetAudioBufferDelay(int delay_ms) = 0; 50 51 // Specifies whether the capture output will be used. The purpose of this is 52 // to allow the echo controller to deactivate some of the processing when the 53 // resulting output is anyway not used, for instance when the endpoint is 54 // muted. 55 // TODO(b/177830919): Make pure virtual. SetCaptureOutputUsage(bool capture_output_used)56 virtual void SetCaptureOutputUsage(bool capture_output_used) {} 57 58 // Returns wheter the signal is altered. 59 virtual bool ActiveProcessing() const = 0; 60 ~EchoControl()61 virtual ~EchoControl() {} 62 }; 63 64 // Interface for a factory that creates EchoControllers. 65 class EchoControlFactory { 66 public: 67 virtual std::unique_ptr<EchoControl> Create(int sample_rate_hz, 68 int num_render_channels, 69 int num_capture_channels) = 0; 70 71 virtual ~EchoControlFactory() = default; 72 }; 73 } // namespace webrtc 74 75 #endif // API_AUDIO_ECHO_CONTROL_H_ 76