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* Copyright (c) 2013 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.
#include "api/array_view.h"
#include "rtc_base/buffer.h"
namespace webrtc {
class AudioDeviceBuffer;
// FineAudioBuffer takes an AudioDeviceBuffer (ADB) which deals with 16-bit PCM
// audio samples corresponding to 10ms of data. It then allows for this data
// to be pulled in a finer or coarser granularity. I.e. interacting with this
// class instead of directly with the AudioDeviceBuffer one can ask for any
// number of audio data samples. This class also ensures that audio data can be
// delivered to the ADB in 10ms chunks when the size of the provided audio
// buffers differs from 10ms.
// As an example: calling DeliverRecordedData() with 5ms buffers will deliver
// accumulated 10ms worth of data to the ADB every second call.
class FineAudioBuffer {
// `device_buffer` is a buffer that provides 10ms of audio data.
FineAudioBuffer(AudioDeviceBuffer* audio_device_buffer);
// Clears buffers and counters dealing with playout and/or recording.
void ResetPlayout();
void ResetRecord();
// Utility methods which returns true if valid parameters are acquired at
// constructions.
bool IsReadyForPlayout() const;
bool IsReadyForRecord() const;
// Copies audio samples into `audio_buffer` where number of requested
// elements is specified by `audio_buffer.size()`. The producer will always
// fill up the audio buffer and if no audio exists, the buffer will contain
// silence instead. The provided delay estimate in `playout_delay_ms` should
// contain an estimate of the latency between when an audio frame is read from
// WebRTC and when it is played out on the speaker.
void GetPlayoutData(rtc::ArrayView<int16_t> audio_buffer,
int playout_delay_ms);
// Consumes the audio data in `audio_buffer` and sends it to the WebRTC layer
// in chunks of 10ms. The sum of the provided delay estimate in
// `record_delay_ms` and the latest `playout_delay_ms` in GetPlayoutData()
// are given to the AEC in the audio processing module.
// They can be fixed values on most platforms and they are ignored if an
// external (hardware/built-in) AEC is used.
// Example: buffer size is 5ms => call #1 stores 5ms of data, call #2 stores
// 5ms of data and sends a total of 10ms to WebRTC and clears the internal
// cache. Call #3 restarts the scheme above.
void DeliverRecordedData(rtc::ArrayView<const int16_t> audio_buffer,
int record_delay_ms);
// Device buffer that works with 10ms chunks of data both for playout and
// for recording. I.e., the WebRTC side will always be asked for audio to be
// played out in 10ms chunks and recorded audio will be sent to WebRTC in
// 10ms chunks as well. This raw pointer is owned by the constructor of this
// class and the owner must ensure that the pointer is valid during the life-
// time of this object.
AudioDeviceBuffer* const audio_device_buffer_;
// Number of audio samples per channel per 10ms. Set once at construction
// based on parameters in `audio_device_buffer`.
const size_t playout_samples_per_channel_10ms_;
const size_t record_samples_per_channel_10ms_;
// Number of audio channels. Set once at construction based on parameters in
// `audio_device_buffer`.
const size_t playout_channels_;
const size_t record_channels_;
// Storage for output samples from which a consumer can read audio buffers
// in any size using GetPlayoutData().
rtc::BufferT<int16_t> playout_buffer_;
// Storage for input samples that are about to be delivered to the WebRTC
// ADB or remains from the last successful delivery of a 10ms audio buffer.
rtc::BufferT<int16_t> record_buffer_;
// Contains latest delay estimate given to GetPlayoutData().
int playout_delay_ms_ = 0;
} // namespace webrtc