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+/*
+ * Copyright (c) 2012 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 MODULES_AUDIO_PROCESSING_INCLUDE_AUDIO_PROCESSING_H_
+#define MODULES_AUDIO_PROCESSING_INCLUDE_AUDIO_PROCESSING_H_
+
+// MSVC++ requires this to be set before any other includes to get M_PI.
+#ifndef _USE_MATH_DEFINES
+#define _USE_MATH_DEFINES
+#endif
+
+#include <math.h>
+#include <stddef.h> // size_t
+#include <stdio.h> // FILE
+#include <string.h>
+
+#include <vector>
+
+#include "absl/strings/string_view.h"
+#include "absl/types/optional.h"
+#include "api/array_view.h"
+#include "api/audio/echo_canceller3_config.h"
+#include "api/audio/echo_control.h"
+#include "api/scoped_refptr.h"
+#include "modules/audio_processing/include/audio_processing_statistics.h"
+#include "rtc_base/arraysize.h"
+#include "rtc_base/ref_count.h"
+#include "rtc_base/system/file_wrapper.h"
+#include "rtc_base/system/rtc_export.h"
+
+namespace rtc {
+class TaskQueue;
+} // namespace rtc
+
+namespace webrtc {
+
+class AecDump;
+class AudioBuffer;
+
+class StreamConfig;
+class ProcessingConfig;
+
+class EchoDetector;
+class CustomAudioAnalyzer;
+class CustomProcessing;
+
+// The Audio Processing Module (APM) provides a collection of voice processing
+// components designed for real-time communications software.
+//
+// APM operates on two audio streams on a frame-by-frame basis. Frames of the
+// primary stream, on which all processing is applied, are passed to
+// `ProcessStream()`. Frames of the reverse direction stream are passed to
+// `ProcessReverseStream()`. On the client-side, this will typically be the
+// near-end (capture) and far-end (render) streams, respectively. APM should be
+// placed in the signal chain as close to the audio hardware abstraction layer
+// (HAL) as possible.
+//
+// On the server-side, the reverse stream will normally not be used, with
+// processing occurring on each incoming stream.
+//
+// Component interfaces follow a similar pattern and are accessed through
+// corresponding getters in APM. All components are disabled at create-time,
+// with default settings that are recommended for most situations. New settings
+// can be applied without enabling a component. Enabling a component triggers
+// memory allocation and initialization to allow it to start processing the
+// streams.
+//
+// Thread safety is provided with the following assumptions to reduce locking
+// overhead:
+// 1. The stream getters and setters are called from the same thread as
+// ProcessStream(). More precisely, stream functions are never called
+// concurrently with ProcessStream().
+// 2. Parameter getters are never called concurrently with the corresponding
+// setter.
+//
+// APM accepts only linear PCM audio data in chunks of ~10 ms (see
+// AudioProcessing::GetFrameSize() for details) and sample rates ranging from
+// 8000 Hz to 384000 Hz. The int16 interfaces use interleaved data, while the
+// float interfaces use deinterleaved data.
+//
+// Usage example, omitting error checking:
+// rtc::scoped_refptr<AudioProcessing> apm = AudioProcessingBuilder().Create();
+//
+// AudioProcessing::Config config;
+// config.echo_canceller.enabled = true;
+// config.echo_canceller.mobile_mode = false;
+//
+// config.gain_controller1.enabled = true;
+// config.gain_controller1.mode =
+// AudioProcessing::Config::GainController1::kAdaptiveAnalog;
+// config.gain_controller1.analog_level_minimum = 0;
+// config.gain_controller1.analog_level_maximum = 255;
+//
+// config.gain_controller2.enabled = true;
+//
+// config.high_pass_filter.enabled = true;
+//
+// apm->ApplyConfig(config)
+//
+// // Start a voice call...
+//
+// // ... Render frame arrives bound for the audio HAL ...
+// apm->ProcessReverseStream(render_frame);
+//
+// // ... Capture frame arrives from the audio HAL ...
+// // Call required set_stream_ functions.
+// apm->set_stream_delay_ms(delay_ms);
+// apm->set_stream_analog_level(analog_level);
+//
+// apm->ProcessStream(capture_frame);
+//
+// // Call required stream_ functions.
+// analog_level = apm->recommended_stream_analog_level();
+// has_voice = apm->stream_has_voice();
+//
+// // Repeat render and capture processing for the duration of the call...
+// // Start a new call...
+// apm->Initialize();
+//
+// // Close the application...
+// apm.reset();
+//
+class RTC_EXPORT AudioProcessing : public rtc::RefCountInterface {
+ public:
+ // The struct below constitutes the new parameter scheme for the audio
+ // processing. It is being introduced gradually and until it is fully
+ // introduced, it is prone to change.
+ // TODO(peah): Remove this comment once the new config scheme is fully rolled
+ // out.
+ //
+ // The parameters and behavior of the audio processing module are controlled
+ // by changing the default values in the AudioProcessing::Config struct.
+ // The config is applied by passing the struct to the ApplyConfig method.
+ //
+ // This config is intended to be used during setup, and to enable/disable
+ // top-level processing effects. Use during processing may cause undesired
+ // submodule resets, affecting the audio quality. Use the RuntimeSetting
+ // construct for runtime configuration.
+ struct RTC_EXPORT Config {
+ // Sets the properties of the audio processing pipeline.
+ struct RTC_EXPORT Pipeline {
+ // Ways to downmix a multi-channel track to mono.
+ enum class DownmixMethod {
+ kAverageChannels, // Average across channels.
+ kUseFirstChannel // Use the first channel.
+ };
+
+ // Maximum allowed processing rate used internally. May only be set to
+ // 32000 or 48000 and any differing values will be treated as 48000.
+ int maximum_internal_processing_rate = 48000;
+ // Allow multi-channel processing of render audio.
+ bool multi_channel_render = false;
+ // Allow multi-channel processing of capture audio when AEC3 is active
+ // or a custom AEC is injected..
+ bool multi_channel_capture = false;
+ // Indicates how to downmix multi-channel capture audio to mono (when
+ // needed).
+ DownmixMethod capture_downmix_method = DownmixMethod::kAverageChannels;
+ } pipeline;
+
+ // Enabled the pre-amplifier. It amplifies the capture signal
+ // before any other processing is done.
+ // TODO(webrtc:5298): Deprecate and use the pre-gain functionality in
+ // capture_level_adjustment instead.
+ struct PreAmplifier {
+ bool enabled = false;
+ float fixed_gain_factor = 1.0f;
+ } pre_amplifier;
+
+ // Functionality for general level adjustment in the capture pipeline. This
+ // should not be used together with the legacy PreAmplifier functionality.
+ struct CaptureLevelAdjustment {
+ bool operator==(const CaptureLevelAdjustment& rhs) const;
+ bool operator!=(const CaptureLevelAdjustment& rhs) const {
+ return !(*this == rhs);
+ }
+ bool enabled = false;
+ // The `pre_gain_factor` scales the signal before any processing is done.
+ float pre_gain_factor = 1.0f;
+ // The `post_gain_factor` scales the signal after all processing is done.
+ float post_gain_factor = 1.0f;
+ struct AnalogMicGainEmulation {
+ bool operator==(const AnalogMicGainEmulation& rhs) const;
+ bool operator!=(const AnalogMicGainEmulation& rhs) const {
+ return !(*this == rhs);
+ }
+ bool enabled = false;
+ // Initial analog gain level to use for the emulated analog gain. Must
+ // be in the range [0...255].
+ int initial_level = 255;
+ } analog_mic_gain_emulation;
+ } capture_level_adjustment;
+
+ struct HighPassFilter {
+ bool enabled = false;
+ bool apply_in_full_band = true;
+ } high_pass_filter;
+
+ struct EchoCanceller {
+ bool enabled = false;
+ bool mobile_mode = false;
+ bool export_linear_aec_output = false;
+ // Enforce the highpass filter to be on (has no effect for the mobile
+ // mode).
+ bool enforce_high_pass_filtering = true;
+ } echo_canceller;
+
+ // Enables background noise suppression.
+ struct NoiseSuppression {
+ bool enabled = false;
+ enum Level { kLow, kModerate, kHigh, kVeryHigh };
+ Level level = kModerate;
+ bool analyze_linear_aec_output_when_available = false;
+ } noise_suppression;
+
+ // Enables transient suppression.
+ struct TransientSuppression {
+ bool enabled = false;
+ } transient_suppression;
+
+ // Enables automatic gain control (AGC) functionality.
+ // The automatic gain control (AGC) component brings the signal to an
+ // appropriate range. This is done by applying a digital gain directly and,
+ // in the analog mode, prescribing an analog gain to be applied at the audio
+ // HAL.
+ // Recommended to be enabled on the client-side.
+ struct RTC_EXPORT GainController1 {
+ bool operator==(const GainController1& rhs) const;
+ bool operator!=(const GainController1& rhs) const {
+ return !(*this == rhs);
+ }
+
+ bool enabled = false;
+ enum Mode {
+ // Adaptive mode intended for use if an analog volume control is
+ // available on the capture device. It will require the user to provide
+ // coupling between the OS mixer controls and AGC through the
+ // stream_analog_level() functions.
+ // It consists of an analog gain prescription for the audio device and a
+ // digital compression stage.
+ kAdaptiveAnalog,
+ // Adaptive mode intended for situations in which an analog volume
+ // control is unavailable. It operates in a similar fashion to the
+ // adaptive analog mode, but with scaling instead applied in the digital
+ // domain. As with the analog mode, it additionally uses a digital
+ // compression stage.
+ kAdaptiveDigital,
+ // Fixed mode which enables only the digital compression stage also used
+ // by the two adaptive modes.
+ // It is distinguished from the adaptive modes by considering only a
+ // short time-window of the input signal. It applies a fixed gain
+ // through most of the input level range, and compresses (gradually
+ // reduces gain with increasing level) the input signal at higher
+ // levels. This mode is preferred on embedded devices where the capture
+ // signal level is predictable, so that a known gain can be applied.
+ kFixedDigital
+ };
+ Mode mode = kAdaptiveAnalog;
+ // Sets the target peak level (or envelope) of the AGC in dBFs (decibels
+ // from digital full-scale). The convention is to use positive values. For
+ // instance, passing in a value of 3 corresponds to -3 dBFs, or a target
+ // level 3 dB below full-scale. Limited to [0, 31].
+ int target_level_dbfs = 3;
+ // Sets the maximum gain the digital compression stage may apply, in dB. A
+ // higher number corresponds to greater compression, while a value of 0
+ // will leave the signal uncompressed. Limited to [0, 90].
+ // For updates after APM setup, use a RuntimeSetting instead.
+ int compression_gain_db = 9;
+ // When enabled, the compression stage will hard limit the signal to the
+ // target level. Otherwise, the signal will be compressed but not limited
+ // above the target level.
+ bool enable_limiter = true;
+
+ // Enables the analog gain controller functionality.
+ struct AnalogGainController {
+ bool enabled = true;
+ // TODO(bugs.webrtc.org/7494): Deprecated. Stop using and remove.
+ int startup_min_volume = 0;
+ // Lowest analog microphone level that will be applied in response to
+ // clipping.
+ int clipped_level_min = 70;
+ // If true, an adaptive digital gain is applied.
+ bool enable_digital_adaptive = true;
+ // Amount the microphone level is lowered with every clipping event.
+ // Limited to (0, 255].
+ int clipped_level_step = 15;
+ // Proportion of clipped samples required to declare a clipping event.
+ // Limited to (0.f, 1.f).
+ float clipped_ratio_threshold = 0.1f;
+ // Time in frames to wait after a clipping event before checking again.
+ // Limited to values higher than 0.
+ int clipped_wait_frames = 300;
+
+ // Enables clipping prediction functionality.
+ struct ClippingPredictor {
+ bool enabled = false;
+ enum Mode {
+ // Clipping event prediction mode with fixed step estimation.
+ kClippingEventPrediction,
+ // Clipped peak estimation mode with adaptive step estimation.
+ kAdaptiveStepClippingPeakPrediction,
+ // Clipped peak estimation mode with fixed step estimation.
+ kFixedStepClippingPeakPrediction,
+ };
+ Mode mode = kClippingEventPrediction;
+ // Number of frames in the sliding analysis window.
+ int window_length = 5;
+ // Number of frames in the sliding reference window.
+ int reference_window_length = 5;
+ // Reference window delay (unit: number of frames).
+ int reference_window_delay = 5;
+ // Clipping prediction threshold (dBFS).
+ float clipping_threshold = -1.0f;
+ // Crest factor drop threshold (dB).
+ float crest_factor_margin = 3.0f;
+ // If true, the recommended clipped level step is used to modify the
+ // analog gain. Otherwise, the predictor runs without affecting the
+ // analog gain.
+ bool use_predicted_step = true;
+ } clipping_predictor;
+ } analog_gain_controller;
+ } gain_controller1;
+
+ // Parameters for AGC2, an Automatic Gain Control (AGC) sub-module which
+ // replaces the AGC sub-module parametrized by `gain_controller1`.
+ // AGC2 brings the captured audio signal to the desired level by combining
+ // three different controllers (namely, input volume controller, adapative
+ // digital controller and fixed digital controller) and a limiter.
+ // TODO(bugs.webrtc.org:7494): Name `GainController` when AGC1 removed.
+ struct RTC_EXPORT GainController2 {
+ bool operator==(const GainController2& rhs) const;
+ bool operator!=(const GainController2& rhs) const {
+ return !(*this == rhs);
+ }
+
+ // AGC2 must be created if and only if `enabled` is true.
+ bool enabled = false;
+
+ // Parameters for the input volume controller, which adjusts the input
+ // volume applied when the audio is captured (e.g., microphone volume on
+ // a soundcard, input volume on HAL).
+ struct InputVolumeController {
+ bool operator==(const InputVolumeController& rhs) const;
+ bool operator!=(const InputVolumeController& rhs) const {
+ return !(*this == rhs);
+ }
+ bool enabled = false;
+ } input_volume_controller;
+
+ // Parameters for the adaptive digital controller, which adjusts and
+ // applies a digital gain after echo cancellation and after noise
+ // suppression.
+ struct RTC_EXPORT AdaptiveDigital {
+ bool operator==(const AdaptiveDigital& rhs) const;
+ bool operator!=(const AdaptiveDigital& rhs) const {
+ return !(*this == rhs);
+ }
+ bool enabled = false;
+ float headroom_db = 6.0f;
+ float max_gain_db = 30.0f;
+ float initial_gain_db = 8.0f;
+ float max_gain_change_db_per_second = 3.0f;
+ float max_output_noise_level_dbfs = -50.0f;
+ } adaptive_digital;
+
+ // Parameters for the fixed digital controller, which applies a fixed
+ // digital gain after the adaptive digital controller and before the
+ // limiter.
+ struct FixedDigital {
+ // By setting `gain_db` to a value greater than zero, the limiter can be
+ // turned into a compressor that first applies a fixed gain.
+ float gain_db = 0.0f;
+ } fixed_digital;
+ } gain_controller2;
+
+ std::string ToString() const;
+ };
+
+ // Specifies the properties of a setting to be passed to AudioProcessing at
+ // runtime.
+ class RuntimeSetting {
+ public:
+ enum class Type {
+ kNotSpecified,
+ kCapturePreGain,
+ kCaptureCompressionGain,
+ kCaptureFixedPostGain,
+ kPlayoutVolumeChange,
+ kCustomRenderProcessingRuntimeSetting,
+ kPlayoutAudioDeviceChange,
+ kCapturePostGain,
+ kCaptureOutputUsed
+ };
+
+ // Play-out audio device properties.
+ struct PlayoutAudioDeviceInfo {
+ int id; // Identifies the audio device.
+ int max_volume; // Maximum play-out volume.
+ };
+
+ RuntimeSetting() : type_(Type::kNotSpecified), value_(0.0f) {}
+ ~RuntimeSetting() = default;
+
+ static RuntimeSetting CreateCapturePreGain(float gain) {
+ return {Type::kCapturePreGain, gain};
+ }
+
+ static RuntimeSetting CreateCapturePostGain(float gain) {
+ return {Type::kCapturePostGain, gain};
+ }
+
+ // Corresponds to Config::GainController1::compression_gain_db, but for
+ // runtime configuration.
+ static RuntimeSetting CreateCompressionGainDb(int gain_db) {
+ RTC_DCHECK_GE(gain_db, 0);
+ RTC_DCHECK_LE(gain_db, 90);
+ return {Type::kCaptureCompressionGain, static_cast<float>(gain_db)};
+ }
+
+ // Corresponds to Config::GainController2::fixed_digital::gain_db, but for
+ // runtime configuration.
+ static RuntimeSetting CreateCaptureFixedPostGain(float gain_db) {
+ RTC_DCHECK_GE(gain_db, 0.0f);
+ RTC_DCHECK_LE(gain_db, 90.0f);
+ return {Type::kCaptureFixedPostGain, gain_db};
+ }
+
+ // Creates a runtime setting to notify play-out (aka render) audio device
+ // changes.
+ static RuntimeSetting CreatePlayoutAudioDeviceChange(
+ PlayoutAudioDeviceInfo audio_device) {
+ return {Type::kPlayoutAudioDeviceChange, audio_device};
+ }
+
+ // Creates a runtime setting to notify play-out (aka render) volume changes.
+ // `volume` is the unnormalized volume, the maximum of which
+ static RuntimeSetting CreatePlayoutVolumeChange(int volume) {
+ return {Type::kPlayoutVolumeChange, volume};
+ }
+
+ static RuntimeSetting CreateCustomRenderSetting(float payload) {
+ return {Type::kCustomRenderProcessingRuntimeSetting, payload};
+ }
+
+ static RuntimeSetting CreateCaptureOutputUsedSetting(
+ bool capture_output_used) {
+ return {Type::kCaptureOutputUsed, capture_output_used};
+ }
+
+ Type type() const { return type_; }
+ // Getters do not return a value but instead modify the argument to protect
+ // from implicit casting.
+ void GetFloat(float* value) const {
+ RTC_DCHECK(value);
+ *value = value_.float_value;
+ }
+ void GetInt(int* value) const {
+ RTC_DCHECK(value);
+ *value = value_.int_value;
+ }
+ void GetBool(bool* value) const {
+ RTC_DCHECK(value);
+ *value = value_.bool_value;
+ }
+ void GetPlayoutAudioDeviceInfo(PlayoutAudioDeviceInfo* value) const {
+ RTC_DCHECK(value);
+ *value = value_.playout_audio_device_info;
+ }
+
+ private:
+ RuntimeSetting(Type id, float value) : type_(id), value_(value) {}
+ RuntimeSetting(Type id, int value) : type_(id), value_(value) {}
+ RuntimeSetting(Type id, PlayoutAudioDeviceInfo value)
+ : type_(id), value_(value) {}
+ Type type_;
+ union U {
+ U() {}
+ U(int value) : int_value(value) {}
+ U(float value) : float_value(value) {}
+ U(PlayoutAudioDeviceInfo value) : playout_audio_device_info(value) {}
+ float float_value;
+ int int_value;
+ bool bool_value;
+ PlayoutAudioDeviceInfo playout_audio_device_info;
+ } value_;
+ };
+
+ ~AudioProcessing() override {}
+
+ // Initializes internal states, while retaining all user settings. This
+ // should be called before beginning to process a new audio stream. However,
+ // it is not necessary to call before processing the first stream after
+ // creation.
+ //
+ // It is also not necessary to call if the audio parameters (sample
+ // rate and number of channels) have changed. Passing updated parameters
+ // directly to `ProcessStream()` and `ProcessReverseStream()` is permissible.
+ // If the parameters are known at init-time though, they may be provided.
+ // TODO(webrtc:5298): Change to return void.
+ virtual int Initialize() = 0;
+
+ // The int16 interfaces require:
+ // - only `NativeRate`s be used
+ // - that the input, output and reverse rates must match
+ // - that `processing_config.output_stream()` matches
+ // `processing_config.input_stream()`.
+ //
+ // The float interfaces accept arbitrary rates and support differing input and
+ // output layouts, but the output must have either one channel or the same
+ // number of channels as the input.
+ virtual int Initialize(const ProcessingConfig& processing_config) = 0;
+
+ // TODO(peah): This method is a temporary solution used to take control
+ // over the parameters in the audio processing module and is likely to change.
+ virtual void ApplyConfig(const Config& config) = 0;
+
+ // TODO(ajm): Only intended for internal use. Make private and friend the
+ // necessary classes?
+ virtual int proc_sample_rate_hz() const = 0;
+ virtual int proc_split_sample_rate_hz() const = 0;
+ virtual size_t num_input_channels() const = 0;
+ virtual size_t num_proc_channels() const = 0;
+ virtual size_t num_output_channels() const = 0;
+ virtual size_t num_reverse_channels() const = 0;
+
+ // Set to true when the output of AudioProcessing will be muted or in some
+ // other way not used. Ideally, the captured audio would still be processed,
+ // but some components may change behavior based on this information.
+ // Default false. This method takes a lock. To achieve this in a lock-less
+ // manner the PostRuntimeSetting can instead be used.
+ virtual void set_output_will_be_muted(bool muted) = 0;
+
+ // Enqueues a runtime setting.
+ virtual void SetRuntimeSetting(RuntimeSetting setting) = 0;
+
+ // Enqueues a runtime setting. Returns a bool indicating whether the
+ // enqueueing was successfull.
+ virtual bool PostRuntimeSetting(RuntimeSetting setting) = 0;
+
+ // Accepts and produces a ~10 ms frame of interleaved 16 bit integer audio as
+ // specified in `input_config` and `output_config`. `src` and `dest` may use
+ // the same memory, if desired.
+ virtual int ProcessStream(const int16_t* const src,
+ const StreamConfig& input_config,
+ const StreamConfig& output_config,
+ int16_t* const dest) = 0;
+
+ // Accepts deinterleaved float audio with the range [-1, 1]. Each element of
+ // `src` points to a channel buffer, arranged according to `input_stream`. At
+ // output, the channels will be arranged according to `output_stream` in
+ // `dest`.
+ //
+ // The output must have one channel or as many channels as the input. `src`
+ // and `dest` may use the same memory, if desired.
+ virtual int ProcessStream(const float* const* src,
+ const StreamConfig& input_config,
+ const StreamConfig& output_config,
+ float* const* dest) = 0;
+
+ // Accepts and produces a ~10 ms frame of interleaved 16 bit integer audio for
+ // the reverse direction audio stream as specified in `input_config` and
+ // `output_config`. `src` and `dest` may use the same memory, if desired.
+ virtual int ProcessReverseStream(const int16_t* const src,
+ const StreamConfig& input_config,
+ const StreamConfig& output_config,
+ int16_t* const dest) = 0;
+
+ // Accepts deinterleaved float audio with the range [-1, 1]. Each element of
+ // `data` points to a channel buffer, arranged according to `reverse_config`.
+ virtual int ProcessReverseStream(const float* const* src,
+ const StreamConfig& input_config,
+ const StreamConfig& output_config,
+ float* const* dest) = 0;
+
+ // Accepts deinterleaved float audio with the range [-1, 1]. Each element
+ // of `data` points to a channel buffer, arranged according to
+ // `reverse_config`.
+ virtual int AnalyzeReverseStream(const float* const* data,
+ const StreamConfig& reverse_config) = 0;
+
+ // Returns the most recently produced ~10 ms of the linear AEC output at a
+ // rate of 16 kHz. If there is more than one capture channel, a mono
+ // representation of the input is returned. Returns true/false to indicate
+ // whether an output returned.
+ virtual bool GetLinearAecOutput(
+ rtc::ArrayView<std::array<float, 160>> linear_output) const = 0;
+
+ // This must be called prior to ProcessStream() if and only if adaptive analog
+ // gain control is enabled, to pass the current analog level from the audio
+ // HAL. Must be within the range [0, 255].
+ virtual void set_stream_analog_level(int level) = 0;
+
+ // When an analog mode is set, this should be called after
+ // `set_stream_analog_level()` and `ProcessStream()` to obtain the recommended
+ // new analog level for the audio HAL. It is the user's responsibility to
+ // apply this level.
+ virtual int recommended_stream_analog_level() const = 0;
+
+ // This must be called if and only if echo processing is enabled.
+ //
+ // Sets the `delay` in ms between ProcessReverseStream() receiving a far-end
+ // frame and ProcessStream() receiving a near-end frame containing the
+ // corresponding echo. On the client-side this can be expressed as
+ // delay = (t_render - t_analyze) + (t_process - t_capture)
+ // where,
+ // - t_analyze is the time a frame is passed to ProcessReverseStream() and
+ // t_render is the time the first sample of the same frame is rendered by
+ // the audio hardware.
+ // - t_capture is the time the first sample of a frame is captured by the
+ // audio hardware and t_process is the time the same frame is passed to
+ // ProcessStream().
+ virtual int set_stream_delay_ms(int delay) = 0;
+ virtual int stream_delay_ms() const = 0;
+
+ // Call to signal that a key press occurred (true) or did not occur (false)
+ // with this chunk of audio.
+ virtual void set_stream_key_pressed(bool key_pressed) = 0;
+
+ // Creates and attaches an webrtc::AecDump for recording debugging
+ // information.
+ // The `worker_queue` may not be null and must outlive the created
+ // AecDump instance. |max_log_size_bytes == -1| means the log size
+ // will be unlimited. `handle` may not be null. The AecDump takes
+ // responsibility for `handle` and closes it in the destructor. A
+ // return value of true indicates that the file has been
+ // sucessfully opened, while a value of false indicates that
+ // opening the file failed.
+ virtual bool CreateAndAttachAecDump(absl::string_view file_name,
+ int64_t max_log_size_bytes,
+ rtc::TaskQueue* worker_queue) = 0;
+ virtual bool CreateAndAttachAecDump(FILE* handle,
+ int64_t max_log_size_bytes,
+ rtc::TaskQueue* worker_queue) = 0;
+
+ // TODO(webrtc:5298) Deprecated variant.
+ // Attaches provided webrtc::AecDump for recording debugging
+ // information. Log file and maximum file size logic is supposed to
+ // be handled by implementing instance of AecDump. Calling this
+ // method when another AecDump is attached resets the active AecDump
+ // with a new one. This causes the d-tor of the earlier AecDump to
+ // be called. The d-tor call may block until all pending logging
+ // tasks are completed.
+ virtual void AttachAecDump(std::unique_ptr<AecDump> aec_dump) = 0;
+
+ // If no AecDump is attached, this has no effect. If an AecDump is
+ // attached, it's destructor is called. The d-tor may block until
+ // all pending logging tasks are completed.
+ virtual void DetachAecDump() = 0;
+
+ // Get audio processing statistics.
+ virtual AudioProcessingStats GetStatistics() = 0;
+ // TODO(webrtc:5298) Deprecated variant. The `has_remote_tracks` argument
+ // should be set if there are active remote tracks (this would usually be true
+ // during a call). If there are no remote tracks some of the stats will not be
+ // set by AudioProcessing, because they only make sense if there is at least
+ // one remote track.
+ virtual AudioProcessingStats GetStatistics(bool has_remote_tracks) = 0;
+
+ // Returns the last applied configuration.
+ virtual AudioProcessing::Config GetConfig() const = 0;
+
+ enum Error {
+ // Fatal errors.
+ kNoError = 0,
+ kUnspecifiedError = -1,
+ kCreationFailedError = -2,
+ kUnsupportedComponentError = -3,
+ kUnsupportedFunctionError = -4,
+ kNullPointerError = -5,
+ kBadParameterError = -6,
+ kBadSampleRateError = -7,
+ kBadDataLengthError = -8,
+ kBadNumberChannelsError = -9,
+ kFileError = -10,
+ kStreamParameterNotSetError = -11,
+ kNotEnabledError = -12,
+
+ // Warnings are non-fatal.
+ // This results when a set_stream_ parameter is out of range. Processing
+ // will continue, but the parameter may have been truncated.
+ kBadStreamParameterWarning = -13
+ };
+
+ // Native rates supported by the integer interfaces.
+ enum NativeRate {
+ kSampleRate8kHz = 8000,
+ kSampleRate16kHz = 16000,
+ kSampleRate32kHz = 32000,
+ kSampleRate48kHz = 48000
+ };
+
+ // TODO(kwiberg): We currently need to support a compiler (Visual C++) that
+ // complains if we don't explicitly state the size of the array here. Remove
+ // the size when that's no longer the case.
+ static constexpr int kNativeSampleRatesHz[4] = {
+ kSampleRate8kHz, kSampleRate16kHz, kSampleRate32kHz, kSampleRate48kHz};
+ static constexpr size_t kNumNativeSampleRates =
+ arraysize(kNativeSampleRatesHz);
+ static constexpr int kMaxNativeSampleRateHz =
+ kNativeSampleRatesHz[kNumNativeSampleRates - 1];
+
+ // APM processes audio in chunks of about 10 ms. See GetFrameSize() for
+ // details.
+ static constexpr int kChunkSizeMs = 10;
+
+ // Returns floor(sample_rate_hz/100): the number of samples per channel used
+ // as input and output to the audio processing module in calls to
+ // ProcessStream, ProcessReverseStream, AnalyzeReverseStream, and
+ // GetLinearAecOutput.
+ //
+ // This is exactly 10 ms for sample rates divisible by 100. For example:
+ // - 48000 Hz (480 samples per channel),
+ // - 44100 Hz (441 samples per channel),
+ // - 16000 Hz (160 samples per channel).
+ //
+ // Sample rates not divisible by 100 are received/produced in frames of
+ // approximately 10 ms. For example:
+ // - 22050 Hz (220 samples per channel, or ~9.98 ms per frame),
+ // - 11025 Hz (110 samples per channel, or ~9.98 ms per frame).
+ // These nondivisible sample rates yield lower audio quality compared to
+ // multiples of 100. Internal resampling to 10 ms frames causes a simulated
+ // clock drift effect which impacts the performance of (for example) echo
+ // cancellation.
+ static int GetFrameSize(int sample_rate_hz) { return sample_rate_hz / 100; }
+};
+
+class RTC_EXPORT AudioProcessingBuilder {
+ public:
+ AudioProcessingBuilder();
+ AudioProcessingBuilder(const AudioProcessingBuilder&) = delete;
+ AudioProcessingBuilder& operator=(const AudioProcessingBuilder&) = delete;
+ ~AudioProcessingBuilder();
+
+ // Sets the APM configuration.
+ AudioProcessingBuilder& SetConfig(const AudioProcessing::Config& config) {
+ config_ = config;
+ return *this;
+ }
+
+ // Sets the echo controller factory to inject when APM is created.
+ AudioProcessingBuilder& SetEchoControlFactory(
+ std::unique_ptr<EchoControlFactory> echo_control_factory) {
+ echo_control_factory_ = std::move(echo_control_factory);
+ return *this;
+ }
+
+ // Sets the capture post-processing sub-module to inject when APM is created.
+ AudioProcessingBuilder& SetCapturePostProcessing(
+ std::unique_ptr<CustomProcessing> capture_post_processing) {
+ capture_post_processing_ = std::move(capture_post_processing);
+ return *this;
+ }
+
+ // Sets the render pre-processing sub-module to inject when APM is created.
+ AudioProcessingBuilder& SetRenderPreProcessing(
+ std::unique_ptr<CustomProcessing> render_pre_processing) {
+ render_pre_processing_ = std::move(render_pre_processing);
+ return *this;
+ }
+
+ // Sets the echo detector to inject when APM is created.
+ AudioProcessingBuilder& SetEchoDetector(
+ rtc::scoped_refptr<EchoDetector> echo_detector) {
+ echo_detector_ = std::move(echo_detector);
+ return *this;
+ }
+
+ // Sets the capture analyzer sub-module to inject when APM is created.
+ AudioProcessingBuilder& SetCaptureAnalyzer(
+ std::unique_ptr<CustomAudioAnalyzer> capture_analyzer) {
+ capture_analyzer_ = std::move(capture_analyzer);
+ return *this;
+ }
+
+ // Creates an APM instance with the specified config or the default one if
+ // unspecified. Injects the specified components transferring the ownership
+ // to the newly created APM instance - i.e., except for the config, the
+ // builder is reset to its initial state.
+ rtc::scoped_refptr<AudioProcessing> Create();
+
+ private:
+ AudioProcessing::Config config_;
+ std::unique_ptr<EchoControlFactory> echo_control_factory_;
+ std::unique_ptr<CustomProcessing> capture_post_processing_;
+ std::unique_ptr<CustomProcessing> render_pre_processing_;
+ rtc::scoped_refptr<EchoDetector> echo_detector_;
+ std::unique_ptr<CustomAudioAnalyzer> capture_analyzer_;
+};
+
+class StreamConfig {
+ public:
+ // sample_rate_hz: The sampling rate of the stream.
+ // num_channels: The number of audio channels in the stream.
+ StreamConfig(int sample_rate_hz = 0, size_t num_channels = 0)
+ : sample_rate_hz_(sample_rate_hz),
+ num_channels_(num_channels),
+ num_frames_(calculate_frames(sample_rate_hz)) {}
+
+ void set_sample_rate_hz(int value) {
+ sample_rate_hz_ = value;
+ num_frames_ = calculate_frames(value);
+ }
+ void set_num_channels(size_t value) { num_channels_ = value; }
+
+ int sample_rate_hz() const { return sample_rate_hz_; }
+
+ // The number of channels in the stream.
+ size_t num_channels() const { return num_channels_; }
+
+ size_t num_frames() const { return num_frames_; }
+ size_t num_samples() const { return num_channels_ * num_frames_; }
+
+ bool operator==(const StreamConfig& other) const {
+ return sample_rate_hz_ == other.sample_rate_hz_ &&
+ num_channels_ == other.num_channels_;
+ }
+
+ bool operator!=(const StreamConfig& other) const { return !(*this == other); }
+
+ private:
+ static size_t calculate_frames(int sample_rate_hz) {
+ return static_cast<size_t>(AudioProcessing::GetFrameSize(sample_rate_hz));
+ }
+
+ int sample_rate_hz_;
+ size_t num_channels_;
+ size_t num_frames_;
+};
+
+class ProcessingConfig {
+ public:
+ enum StreamName {
+ kInputStream,
+ kOutputStream,
+ kReverseInputStream,
+ kReverseOutputStream,
+ kNumStreamNames,
+ };
+
+ const StreamConfig& input_stream() const {
+ return streams[StreamName::kInputStream];
+ }
+ const StreamConfig& output_stream() const {
+ return streams[StreamName::kOutputStream];
+ }
+ const StreamConfig& reverse_input_stream() const {
+ return streams[StreamName::kReverseInputStream];
+ }
+ const StreamConfig& reverse_output_stream() const {
+ return streams[StreamName::kReverseOutputStream];
+ }
+
+ StreamConfig& input_stream() { return streams[StreamName::kInputStream]; }
+ StreamConfig& output_stream() { return streams[StreamName::kOutputStream]; }
+ StreamConfig& reverse_input_stream() {
+ return streams[StreamName::kReverseInputStream];
+ }
+ StreamConfig& reverse_output_stream() {
+ return streams[StreamName::kReverseOutputStream];
+ }
+
+ bool operator==(const ProcessingConfig& other) const {
+ for (int i = 0; i < StreamName::kNumStreamNames; ++i) {
+ if (this->streams[i] != other.streams[i]) {
+ return false;
+ }
+ }
+ return true;
+ }
+
+ bool operator!=(const ProcessingConfig& other) const {
+ return !(*this == other);
+ }
+
+ StreamConfig streams[StreamName::kNumStreamNames];
+};
+
+// Experimental interface for a custom analysis submodule.
+class CustomAudioAnalyzer {
+ public:
+ // (Re-) Initializes the submodule.
+ virtual void Initialize(int sample_rate_hz, int num_channels) = 0;
+ // Analyzes the given capture or render signal.
+ virtual void Analyze(const AudioBuffer* audio) = 0;
+ // Returns a string representation of the module state.
+ virtual std::string ToString() const = 0;
+
+ virtual ~CustomAudioAnalyzer() {}
+};
+
+// Interface for a custom processing submodule.
+class CustomProcessing {
+ public:
+ // (Re-)Initializes the submodule.
+ virtual void Initialize(int sample_rate_hz, int num_channels) = 0;
+ // Processes the given capture or render signal.
+ virtual void Process(AudioBuffer* audio) = 0;
+ // Returns a string representation of the module state.
+ virtual std::string ToString() const = 0;
+ // Handles RuntimeSettings. TODO(webrtc:9262): make pure virtual
+ // after updating dependencies.
+ virtual void SetRuntimeSetting(AudioProcessing::RuntimeSetting setting);
+
+ virtual ~CustomProcessing() {}
+};
+
+// Interface for an echo detector submodule.
+class EchoDetector : public rtc::RefCountInterface {
+ public:
+ // (Re-)Initializes the submodule.
+ virtual void Initialize(int capture_sample_rate_hz,
+ int num_capture_channels,
+ int render_sample_rate_hz,
+ int num_render_channels) = 0;
+
+ // Analysis (not changing) of the first channel of the render signal.
+ virtual void AnalyzeRenderAudio(rtc::ArrayView<const float> render_audio) = 0;
+
+ // Analysis (not changing) of the capture signal.
+ virtual void AnalyzeCaptureAudio(
+ rtc::ArrayView<const float> capture_audio) = 0;
+
+ struct Metrics {
+ absl::optional<double> echo_likelihood;
+ absl::optional<double> echo_likelihood_recent_max;
+ };
+
+ // Collect current metrics from the echo detector.
+ virtual Metrics GetMetrics() const = 0;
+};
+
+} // namespace webrtc
+
+#endif // MODULES_AUDIO_PROCESSING_INCLUDE_AUDIO_PROCESSING_H_