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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.
*/
#include "modules/audio_processing/aec3/render_delay_buffer.h"
#include <string.h>
#include <algorithm>
#include <atomic>
#include <cmath>
#include <memory>
#include <numeric>
#include <vector>
#include "absl/types/optional.h"
#include "api/array_view.h"
#include "api/audio/echo_canceller3_config.h"
#include "modules/audio_processing/aec3/aec3_common.h"
#include "modules/audio_processing/aec3/aec3_fft.h"
#include "modules/audio_processing/aec3/alignment_mixer.h"
#include "modules/audio_processing/aec3/block_buffer.h"
#include "modules/audio_processing/aec3/decimator.h"
#include "modules/audio_processing/aec3/downsampled_render_buffer.h"
#include "modules/audio_processing/aec3/fft_buffer.h"
#include "modules/audio_processing/aec3/fft_data.h"
#include "modules/audio_processing/aec3/render_buffer.h"
#include "modules/audio_processing/aec3/spectrum_buffer.h"
#include "modules/audio_processing/logging/apm_data_dumper.h"
#include "rtc_base/checks.h"
#include "rtc_base/logging.h"
#include "system_wrappers/include/field_trial.h"
namespace webrtc {
namespace {
class RenderDelayBufferImpl final : public RenderDelayBuffer {
public:
RenderDelayBufferImpl(const EchoCanceller3Config& config,
int sample_rate_hz,
size_t num_render_channels);
RenderDelayBufferImpl() = delete;
~RenderDelayBufferImpl() override;
void Reset() override;
BufferingEvent Insert(const Block& block) override;
BufferingEvent PrepareCaptureProcessing() override;
void HandleSkippedCaptureProcessing() override;
bool AlignFromDelay(size_t delay) override;
void AlignFromExternalDelay() override;
size_t Delay() const override { return ComputeDelay(); }
size_t MaxDelay() const override {
return blocks_.buffer.size() - 1 - buffer_headroom_;
}
RenderBuffer* GetRenderBuffer() override { return &echo_remover_buffer_; }
const DownsampledRenderBuffer& GetDownsampledRenderBuffer() const override {
return low_rate_;
}
int BufferLatency() const;
void SetAudioBufferDelay(int delay_ms) override;
bool HasReceivedBufferDelay() override;
private:
static std::atomic<int> instance_count_;
std::unique_ptr<ApmDataDumper> data_dumper_;
const Aec3Optimization optimization_;
const EchoCanceller3Config config_;
const float render_linear_amplitude_gain_;
const rtc::LoggingSeverity delay_log_level_;
size_t down_sampling_factor_;
const int sub_block_size_;
BlockBuffer blocks_;
SpectrumBuffer spectra_;
FftBuffer ffts_;
absl::optional<size_t> delay_;
RenderBuffer echo_remover_buffer_;
DownsampledRenderBuffer low_rate_;
AlignmentMixer render_mixer_;
Decimator render_decimator_;
const Aec3Fft fft_;
std::vector<float> render_ds_;
const int buffer_headroom_;
bool last_call_was_render_ = false;
int num_api_calls_in_a_row_ = 0;
int max_observed_jitter_ = 1;
int64_t capture_call_counter_ = 0;
int64_t render_call_counter_ = 0;
bool render_activity_ = false;
size_t render_activity_counter_ = 0;
absl::optional<int> external_audio_buffer_delay_;
bool external_audio_buffer_delay_verified_after_reset_ = false;
size_t min_latency_blocks_ = 0;
size_t excess_render_detection_counter_ = 0;
int MapDelayToTotalDelay(size_t delay) const;
int ComputeDelay() const;
void ApplyTotalDelay(int delay);
void InsertBlock(const Block& block, int previous_write);
bool DetectActiveRender(rtc::ArrayView<const float> x) const;
bool DetectExcessRenderBlocks();
void IncrementWriteIndices();
void IncrementLowRateReadIndices();
void IncrementReadIndices();
bool RenderOverrun();
bool RenderUnderrun();
};
std::atomic<int> RenderDelayBufferImpl::instance_count_ = 0;
RenderDelayBufferImpl::RenderDelayBufferImpl(const EchoCanceller3Config& config,
int sample_rate_hz,
size_t num_render_channels)
: data_dumper_(new ApmDataDumper(instance_count_.fetch_add(1) + 1)),
optimization_(DetectOptimization()),
config_(config),
render_linear_amplitude_gain_(
std::pow(10.0f, config_.render_levels.render_power_gain_db / 20.f)),
delay_log_level_(config_.delay.log_warning_on_delay_changes
? rtc::LS_WARNING
: rtc::LS_VERBOSE),
down_sampling_factor_(config.delay.down_sampling_factor),
sub_block_size_(static_cast<int>(down_sampling_factor_ > 0
? kBlockSize / down_sampling_factor_
: kBlockSize)),
blocks_(GetRenderDelayBufferSize(down_sampling_factor_,
config.delay.num_filters,
config.filter.refined.length_blocks),
NumBandsForRate(sample_rate_hz),
num_render_channels),
spectra_(blocks_.buffer.size(), num_render_channels),
ffts_(blocks_.buffer.size(), num_render_channels),
delay_(config_.delay.default_delay),
echo_remover_buffer_(&blocks_, &spectra_, &ffts_),
low_rate_(GetDownSampledBufferSize(down_sampling_factor_,
config.delay.num_filters)),
render_mixer_(num_render_channels, config.delay.render_alignment_mixing),
render_decimator_(down_sampling_factor_),
fft_(),
render_ds_(sub_block_size_, 0.f),
buffer_headroom_(config.filter.refined.length_blocks) {
RTC_DCHECK_EQ(blocks_.buffer.size(), ffts_.buffer.size());
RTC_DCHECK_EQ(spectra_.buffer.size(), ffts_.buffer.size());
for (size_t i = 0; i < blocks_.buffer.size(); ++i) {
RTC_DCHECK_EQ(blocks_.buffer[i].NumChannels(), ffts_.buffer[i].size());
RTC_DCHECK_EQ(spectra_.buffer[i].size(), ffts_.buffer[i].size());
}
Reset();
}
RenderDelayBufferImpl::~RenderDelayBufferImpl() = default;
// Resets the buffer delays and clears the reported delays.
void RenderDelayBufferImpl::Reset() {
last_call_was_render_ = false;
num_api_calls_in_a_row_ = 1;
min_latency_blocks_ = 0;
excess_render_detection_counter_ = 0;
// Initialize the read index to one sub-block before the write index.
low_rate_.read = low_rate_.OffsetIndex(low_rate_.write, sub_block_size_);
// Check for any external audio buffer delay and whether it is feasible.
if (external_audio_buffer_delay_) {
const int headroom = 2;
size_t audio_buffer_delay_to_set;
// Minimum delay is 1 (like the low-rate render buffer).
if (*external_audio_buffer_delay_ <= headroom) {
audio_buffer_delay_to_set = 1;
} else {
audio_buffer_delay_to_set = *external_audio_buffer_delay_ - headroom;
}
audio_buffer_delay_to_set = std::min(audio_buffer_delay_to_set, MaxDelay());
// When an external delay estimate is available, use that delay as the
// initial render buffer delay.
ApplyTotalDelay(audio_buffer_delay_to_set);
delay_ = ComputeDelay();
external_audio_buffer_delay_verified_after_reset_ = false;
} else {
// If an external delay estimate is not available, use that delay as the
// initial delay. Set the render buffer delays to the default delay.
ApplyTotalDelay(config_.delay.default_delay);
// Unset the delays which are set by AlignFromDelay.
delay_ = absl::nullopt;
}
}
// Inserts a new block into the render buffers.
RenderDelayBuffer::BufferingEvent RenderDelayBufferImpl::Insert(
const Block& block) {
++render_call_counter_;
if (delay_) {
if (!last_call_was_render_) {
last_call_was_render_ = true;
num_api_calls_in_a_row_ = 1;
} else {
if (++num_api_calls_in_a_row_ > max_observed_jitter_) {
max_observed_jitter_ = num_api_calls_in_a_row_;
RTC_LOG_V(delay_log_level_)
<< "New max number api jitter observed at render block "
<< render_call_counter_ << ": " << num_api_calls_in_a_row_
<< " blocks";
}
}
}
// Increase the write indices to where the new blocks should be written.
const int previous_write = blocks_.write;
IncrementWriteIndices();
// Allow overrun and do a reset when render overrun occurrs due to more render
// data being inserted than capture data is received.
BufferingEvent event =
RenderOverrun() ? BufferingEvent::kRenderOverrun : BufferingEvent::kNone;
// Detect and update render activity.
if (!render_activity_) {
render_activity_counter_ +=
DetectActiveRender(block.View(/*band=*/0, /*channel=*/0)) ? 1 : 0;
render_activity_ = render_activity_counter_ >= 20;
}
// Insert the new render block into the specified position.
InsertBlock(block, previous_write);
if (event != BufferingEvent::kNone) {
Reset();
}
return event;
}
void RenderDelayBufferImpl::HandleSkippedCaptureProcessing() {
++capture_call_counter_;
}
// Prepares the render buffers for processing another capture block.
RenderDelayBuffer::BufferingEvent
RenderDelayBufferImpl::PrepareCaptureProcessing() {
RenderDelayBuffer::BufferingEvent event = BufferingEvent::kNone;
++capture_call_counter_;
if (delay_) {
if (last_call_was_render_) {
last_call_was_render_ = false;
num_api_calls_in_a_row_ = 1;
} else {
if (++num_api_calls_in_a_row_ > max_observed_jitter_) {
max_observed_jitter_ = num_api_calls_in_a_row_;
RTC_LOG_V(delay_log_level_)
<< "New max number api jitter observed at capture block "
<< capture_call_counter_ << ": " << num_api_calls_in_a_row_
<< " blocks";
}
}
}
if (DetectExcessRenderBlocks()) {
// Too many render blocks compared to capture blocks. Risk of delay ending
// up before the filter used by the delay estimator.
RTC_LOG_V(delay_log_level_)
<< "Excess render blocks detected at block " << capture_call_counter_;
Reset();
event = BufferingEvent::kRenderOverrun;
} else if (RenderUnderrun()) {
// Don't increment the read indices of the low rate buffer if there is a
// render underrun.
RTC_LOG_V(delay_log_level_)
<< "Render buffer underrun detected at block " << capture_call_counter_;
IncrementReadIndices();
// Incrementing the buffer index without increasing the low rate buffer
// index means that the delay is reduced by one.
if (delay_ && *delay_ > 0)
delay_ = *delay_ - 1;
event = BufferingEvent::kRenderUnderrun;
} else {
// Increment the read indices in the render buffers to point to the most
// recent block to use in the capture processing.
IncrementLowRateReadIndices();
IncrementReadIndices();
}
echo_remover_buffer_.SetRenderActivity(render_activity_);
if (render_activity_) {
render_activity_counter_ = 0;
render_activity_ = false;
}
return event;
}
// Sets the delay and returns a bool indicating whether the delay was changed.
bool RenderDelayBufferImpl::AlignFromDelay(size_t delay) {
RTC_DCHECK(!config_.delay.use_external_delay_estimator);
if (!external_audio_buffer_delay_verified_after_reset_ &&
external_audio_buffer_delay_ && delay_) {
int difference = static_cast<int>(delay) - static_cast<int>(*delay_);
RTC_LOG_V(delay_log_level_)
<< "Mismatch between first estimated delay after reset "
"and externally reported audio buffer delay: "
<< difference << " blocks";
external_audio_buffer_delay_verified_after_reset_ = true;
}
if (delay_ && *delay_ == delay) {
return false;
}
delay_ = delay;
// Compute the total delay and limit the delay to the allowed range.
int total_delay = MapDelayToTotalDelay(*delay_);
total_delay =
std::min(MaxDelay(), static_cast<size_t>(std::max(total_delay, 0)));
// Apply the delay to the buffers.
ApplyTotalDelay(total_delay);
return true;
}
void RenderDelayBufferImpl::SetAudioBufferDelay(int delay_ms) {
if (!external_audio_buffer_delay_) {
RTC_LOG_V(delay_log_level_)
<< "Receiving a first externally reported audio buffer delay of "
<< delay_ms << " ms.";
}
// Convert delay from milliseconds to blocks (rounded down).
external_audio_buffer_delay_ = delay_ms / 4;
}
bool RenderDelayBufferImpl::HasReceivedBufferDelay() {
return external_audio_buffer_delay_.has_value();
}
// Maps the externally computed delay to the delay used internally.
int RenderDelayBufferImpl::MapDelayToTotalDelay(
size_t external_delay_blocks) const {
const int latency_blocks = BufferLatency();
return latency_blocks + static_cast<int>(external_delay_blocks);
}
// Returns the delay (not including call jitter).
int RenderDelayBufferImpl::ComputeDelay() const {
const int latency_blocks = BufferLatency();
int internal_delay = spectra_.read >= spectra_.write
? spectra_.read - spectra_.write
: spectra_.size + spectra_.read - spectra_.write;
return internal_delay - latency_blocks;
}
// Set the read indices according to the delay.
void RenderDelayBufferImpl::ApplyTotalDelay(int delay) {
RTC_LOG_V(delay_log_level_)
<< "Applying total delay of " << delay << " blocks.";
blocks_.read = blocks_.OffsetIndex(blocks_.write, -delay);
spectra_.read = spectra_.OffsetIndex(spectra_.write, delay);
ffts_.read = ffts_.OffsetIndex(ffts_.write, delay);
}
void RenderDelayBufferImpl::AlignFromExternalDelay() {
RTC_DCHECK(config_.delay.use_external_delay_estimator);
if (external_audio_buffer_delay_) {
const int64_t delay = render_call_counter_ - capture_call_counter_ +
*external_audio_buffer_delay_;
const int64_t delay_with_headroom =
delay - config_.delay.delay_headroom_samples / kBlockSize;
ApplyTotalDelay(delay_with_headroom);
}
}
// Inserts a block into the render buffers.
void RenderDelayBufferImpl::InsertBlock(const Block& block,
int previous_write) {
auto& b = blocks_;
auto& lr = low_rate_;
auto& ds = render_ds_;
auto& f = ffts_;
auto& s = spectra_;
const size_t num_bands = b.buffer[b.write].NumBands();
const size_t num_render_channels = b.buffer[b.write].NumChannels();
RTC_DCHECK_EQ(block.NumBands(), num_bands);
RTC_DCHECK_EQ(block.NumChannels(), num_render_channels);
for (size_t band = 0; band < num_bands; ++band) {
for (size_t ch = 0; ch < num_render_channels; ++ch) {
std::copy(block.begin(band, ch), block.end(band, ch),
b.buffer[b.write].begin(band, ch));
}
}
if (render_linear_amplitude_gain_ != 1.f) {
for (size_t band = 0; band < num_bands; ++band) {
for (size_t ch = 0; ch < num_render_channels; ++ch) {
rtc::ArrayView<float, kBlockSize> b_view =
b.buffer[b.write].View(band, ch);
for (float& sample : b_view) {
sample *= render_linear_amplitude_gain_;
}
}
}
}
std::array<float, kBlockSize> downmixed_render;
render_mixer_.ProduceOutput(b.buffer[b.write], downmixed_render);
render_decimator_.Decimate(downmixed_render, ds);
data_dumper_->DumpWav("aec3_render_decimator_output", ds.size(), ds.data(),
16000 / down_sampling_factor_, 1);
std::copy(ds.rbegin(), ds.rend(), lr.buffer.begin() + lr.write);
for (int channel = 0; channel < b.buffer[b.write].NumChannels(); ++channel) {
fft_.PaddedFft(b.buffer[b.write].View(/*band=*/0, channel),
b.buffer[previous_write].View(/*band=*/0, channel),
&f.buffer[f.write][channel]);
f.buffer[f.write][channel].Spectrum(optimization_,
s.buffer[s.write][channel]);
}
}
bool RenderDelayBufferImpl::DetectActiveRender(
rtc::ArrayView<const float> x) const {
const float x_energy = std::inner_product(x.begin(), x.end(), x.begin(), 0.f);
return x_energy > (config_.render_levels.active_render_limit *
config_.render_levels.active_render_limit) *
kFftLengthBy2;
}
bool RenderDelayBufferImpl::DetectExcessRenderBlocks() {
bool excess_render_detected = false;
const size_t latency_blocks = static_cast<size_t>(BufferLatency());
// The recently seen minimum latency in blocks. Should be close to 0.
min_latency_blocks_ = std::min(min_latency_blocks_, latency_blocks);
// After processing a configurable number of blocks the minimum latency is
// checked.
if (++excess_render_detection_counter_ >=
config_.buffering.excess_render_detection_interval_blocks) {
// If the minimum latency is not lower than the threshold there have been
// more render than capture frames.
excess_render_detected = min_latency_blocks_ >
config_.buffering.max_allowed_excess_render_blocks;
// Reset the counter and let the minimum latency be the current latency.
min_latency_blocks_ = latency_blocks;
excess_render_detection_counter_ = 0;
}
data_dumper_->DumpRaw("aec3_latency_blocks", latency_blocks);
data_dumper_->DumpRaw("aec3_min_latency_blocks", min_latency_blocks_);
data_dumper_->DumpRaw("aec3_excess_render_detected", excess_render_detected);
return excess_render_detected;
}
// Computes the latency in the buffer (the number of unread sub-blocks).
int RenderDelayBufferImpl::BufferLatency() const {
const DownsampledRenderBuffer& l = low_rate_;
int latency_samples = (l.buffer.size() + l.read - l.write) % l.buffer.size();
int latency_blocks = latency_samples / sub_block_size_;
return latency_blocks;
}
// Increments the write indices for the render buffers.
void RenderDelayBufferImpl::IncrementWriteIndices() {
low_rate_.UpdateWriteIndex(-sub_block_size_);
blocks_.IncWriteIndex();
spectra_.DecWriteIndex();
ffts_.DecWriteIndex();
}
// Increments the read indices of the low rate render buffers.
void RenderDelayBufferImpl::IncrementLowRateReadIndices() {
low_rate_.UpdateReadIndex(-sub_block_size_);
}
// Increments the read indices for the render buffers.
void RenderDelayBufferImpl::IncrementReadIndices() {
if (blocks_.read != blocks_.write) {
blocks_.IncReadIndex();
spectra_.DecReadIndex();
ffts_.DecReadIndex();
}
}
// Checks for a render buffer overrun.
bool RenderDelayBufferImpl::RenderOverrun() {
return low_rate_.read == low_rate_.write || blocks_.read == blocks_.write;
}
// Checks for a render buffer underrun.
bool RenderDelayBufferImpl::RenderUnderrun() {
return low_rate_.read == low_rate_.write;
}
} // namespace
RenderDelayBuffer* RenderDelayBuffer::Create(const EchoCanceller3Config& config,
int sample_rate_hz,
size_t num_render_channels) {
return new RenderDelayBufferImpl(config, sample_rate_hz, num_render_channels);
}
} // namespace webrtc