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/*
* Copyright (c) 2017 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 <numeric>
#include "modules/audio_processing/aec3/aec3_common.h"
#include "modules/audio_processing/aec3/aec3_fft.h"
#include "modules/audio_processing/aec3/block_processor.h"
#include "modules/audio_processing/aec3/decimator.h"
#include "modules/audio_processing/aec3/fft_buffer.h"
#include "modules/audio_processing/aec3/fft_data.h"
#include "modules/audio_processing/aec3/matrix_buffer.h"
#include "rtc_base/atomicops.h"
#include "rtc_base/checks.h"
#include "rtc_base/constructormagic.h"
#include "rtc_base/logging.h"
#include "system_wrappers/include/field_trial.h"
namespace webrtc {
namespace {
bool EnableZeroExternalDelayHeadroom() {
return !field_trial::IsEnabled(
"WebRTC-Aec3ZeroExternalDelayHeadroomKillSwitch");
}
size_t GetDownSamplingFactor(const EchoCanceller3Config& config) {
// Do not use down sampling factor 8 if kill switch is triggered.
return (config.delay.down_sampling_factor == 8 &&
field_trial::IsEnabled("WebRTC-Aec3DownSamplingFactor8KillSwitch"))
? 4
: config.delay.down_sampling_factor;
}
class RenderDelayBufferImpl final : public RenderDelayBuffer {
public:
RenderDelayBufferImpl(const EchoCanceller3Config& config, size_t num_bands);
~RenderDelayBufferImpl() override;
void Reset() override;
BufferingEvent Insert(const std::vector<std::vector<float>>& block) override;
BufferingEvent PrepareCaptureProcessing() override;
bool SetDelay(size_t delay) override;
size_t Delay() const override { return MapInternalDelayToExternalDelay(); }
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_;
}
bool CausalDelay(size_t delay) const override;
void SetAudioBufferDelay(size_t delay_ms) override;
private:
static int instance_count_;
std::unique_ptr<ApmDataDumper> data_dumper_;
const Aec3Optimization optimization_;
const EchoCanceller3Config config_;
size_t down_sampling_factor_;
const bool use_zero_external_delay_headroom_;
const int sub_block_size_;
MatrixBuffer blocks_;
VectorBuffer spectra_;
FftBuffer ffts_;
absl::optional<size_t> delay_;
absl::optional<int> internal_delay_;
RenderBuffer echo_remover_buffer_;
DownsampledRenderBuffer low_rate_;
Decimator render_decimator_;
const std::vector<std::vector<float>> zero_block_;
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;
size_t capture_call_counter_ = 0;
size_t render_call_counter_ = 0;
bool render_activity_ = false;
size_t render_activity_counter_ = 0;
absl::optional<size_t> external_audio_buffer_delay_;
bool external_delay_verified_after_reset_ = false;
int LowRateBufferOffset() const { return DelayEstimatorOffset(config_) >> 1; }
int MapExternalDelayToInternalDelay(size_t external_delay_blocks) const;
int MapInternalDelayToExternalDelay() const;
void ApplyDelay(int delay);
void InsertBlock(const std::vector<std::vector<float>>& block,
int previous_write);
bool DetectActiveRender(rtc::ArrayView<const float> x) const;
RTC_DISALLOW_IMPLICIT_CONSTRUCTORS(RenderDelayBufferImpl);
};
// Increases the write indices for the render buffers.
void IncreaseWriteIndices(int sub_block_size,
MatrixBuffer* blocks,
VectorBuffer* spectra,
FftBuffer* ffts,
DownsampledRenderBuffer* low_rate) {
low_rate->UpdateWriteIndex(-sub_block_size);
blocks->IncWriteIndex();
spectra->DecWriteIndex();
ffts->DecWriteIndex();
}
// Increases the read indices for the render buffers.
void IncreaseReadIndices(const absl::optional<int>& delay,
int sub_block_size,
MatrixBuffer* blocks,
VectorBuffer* spectra,
FftBuffer* ffts,
DownsampledRenderBuffer* low_rate) {
RTC_DCHECK_NE(low_rate->read, low_rate->write);
low_rate->UpdateReadIndex(-sub_block_size);
if (blocks->read != blocks->write) {
blocks->IncReadIndex();
spectra->DecReadIndex();
ffts->DecReadIndex();
} else {
// Only allow underrun for blocks_ when the delay is not set.
RTC_DCHECK(!delay);
}
}
// Checks for a render buffer overrun.
bool RenderOverrun(const MatrixBuffer& b, const DownsampledRenderBuffer& l) {
return l.read == l.write || b.read == b.write;
}
// Checks for a render buffer underrun. If the delay is not specified, only the
// low rate buffer underrun is counted as the delay offset for the other buffers
// is unknown.
bool RenderUnderrun(const absl::optional<int>& delay,
const MatrixBuffer& b,
const DownsampledRenderBuffer& l) {
return l.read == l.write || (delay && b.read == b.write);
}
// Computes the latency in the buffer (the number of unread elements).
int BufferLatency(const DownsampledRenderBuffer& l) {
return (l.buffer.size() + l.read - l.write) % l.buffer.size();
}
// Computes the mismatch between the number of render and capture calls based on
// the known offset (achieved during reset) of the low rate buffer.
bool ApiCallSkew(const DownsampledRenderBuffer& low_rate_buffer,
int sub_block_size,
int low_rate_buffer_offset_sub_blocks) {
int latency = BufferLatency(low_rate_buffer);
int skew = abs(low_rate_buffer_offset_sub_blocks * sub_block_size - latency);
int skew_limit = low_rate_buffer_offset_sub_blocks * sub_block_size;
return skew >= skew_limit;
}
int RenderDelayBufferImpl::instance_count_ = 0;
RenderDelayBufferImpl::RenderDelayBufferImpl(const EchoCanceller3Config& config,
size_t num_bands)
: data_dumper_(
new ApmDataDumper(rtc::AtomicOps::Increment(&instance_count_))),
optimization_(DetectOptimization()),
config_(config),
down_sampling_factor_(GetDownSamplingFactor(config)),
use_zero_external_delay_headroom_(EnableZeroExternalDelayHeadroom()),
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.main.length_blocks),
num_bands,
kBlockSize),
spectra_(blocks_.buffer.size(), kFftLengthBy2Plus1),
ffts_(blocks_.buffer.size()),
delay_(config_.delay.default_delay),
echo_remover_buffer_(&blocks_, &spectra_, &ffts_),
low_rate_(GetDownSampledBufferSize(down_sampling_factor_,
config.delay.num_filters)),
render_decimator_(down_sampling_factor_),
zero_block_(num_bands, std::vector<float>(kBlockSize, 0.f)),
fft_(),
render_ds_(sub_block_size_, 0.f),
buffer_headroom_(config.filter.main.length_blocks) {
RTC_DCHECK_EQ(blocks_.buffer.size(), ffts_.buffer.size());
RTC_DCHECK_EQ(spectra_.buffer.size(), ffts_.buffer.size());
// Necessary condition to avoid unrecoverable echp due to noncausal alignment.
RTC_DCHECK_EQ(DelayEstimatorOffset(config_), LowRateBufferOffset() * 2);
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;
// Pre-fill the low rate buffer (which is used for delay estimation) to add
// headroom for the allowed api call jitter.
low_rate_.read = low_rate_.OffsetIndex(
low_rate_.write, LowRateBufferOffset() * sub_block_size_);
// Check for any external audio buffer delay and whether it is feasible.
if (external_audio_buffer_delay_) {
const size_t headroom = use_zero_external_delay_headroom_ ? 0 : 2;
size_t external_delay_to_set = 0;
if (*external_audio_buffer_delay_ < headroom) {
external_delay_to_set = 0;
} else {
external_delay_to_set = *external_audio_buffer_delay_ - headroom;
}
external_delay_to_set = std::min(external_delay_to_set, MaxDelay());
// When an external delay estimate is available, use that delay as the
// initial render buffer delay.
internal_delay_ = external_delay_to_set;
ApplyDelay(*internal_delay_);
delay_ = MapInternalDelayToExternalDelay();
external_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.
ApplyDelay(config_.delay.default_delay);
// Unset the delays which are set by SetDelay.
delay_ = absl::nullopt;
internal_delay_ = absl::nullopt;
}
}
// Inserts a new block into the render buffers.
RenderDelayBuffer::BufferingEvent RenderDelayBufferImpl::Insert(
const std::vector<std::vector<float>>& 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(LS_WARNING)
<< "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;
IncreaseWriteIndices(sub_block_size_, &blocks_, &spectra_, &ffts_,
&low_rate_);
// 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(blocks_, low_rate_)
? BufferingEvent::kRenderOverrun
: BufferingEvent::kNone;
// Detect and update render activity.
if (!render_activity_) {
render_activity_counter_ += DetectActiveRender(block[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;
}
// Prepares the render buffers for processing another capture block.
RenderDelayBuffer::BufferingEvent
RenderDelayBufferImpl::PrepareCaptureProcessing() {
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(LS_WARNING)
<< "New max number api jitter observed at capture block "
<< capture_call_counter_ << ": " << num_api_calls_in_a_row_
<< " blocks";
}
}
}
if (RenderUnderrun(internal_delay_, blocks_, low_rate_)) {
// Don't increase the read indices if there is a render underrun.
event = BufferingEvent::kRenderUnderrun;
} else {
// Increase the read indices in the render buffers to point to the most
// recent block to use in the capture processing.
IncreaseReadIndices(internal_delay_, sub_block_size_, &blocks_, &spectra_,
&ffts_, &low_rate_);
// Check for skew in the API calls which, if too large, causes the delay
// estimation to be noncausal. Doing this check after the render indice
// increase saves one unit of allowed skew. Note that the skew check only
// should need to be one-sided as one of the skew directions results in an
// underrun.
bool skew = ApiCallSkew(low_rate_, sub_block_size_, LowRateBufferOffset());
event = skew ? BufferingEvent::kApiCallSkew : BufferingEvent::kNone;
}
if (event != BufferingEvent::kNone) {
Reset();
}
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::SetDelay(size_t delay) {
if (!external_delay_verified_after_reset_ && external_audio_buffer_delay_ &&
delay_) {
int difference = static_cast<int>(delay) - static_cast<int>(*delay_);
RTC_LOG(LS_WARNING) << "Mismatch between first estimated delay after reset "
"and external delay: "
<< difference << " blocks";
external_delay_verified_after_reset_ = true;
}
if (delay_ && *delay_ == delay) {
return false;
}
delay_ = delay;
// Compute the internal delay and limit the delay to the allowed range.
int internal_delay = MapExternalDelayToInternalDelay(*delay_);
internal_delay_ =
std::min(MaxDelay(), static_cast<size_t>(std::max(internal_delay, 0)));
// Apply the delay to the buffers.
ApplyDelay(*internal_delay_);
return true;
}
// Returns whether the specified delay is causal.
bool RenderDelayBufferImpl::CausalDelay(size_t delay) const {
// Compute the internal delay and limit the delay to the allowed range.
int internal_delay = MapExternalDelayToInternalDelay(delay);
internal_delay =
std::min(MaxDelay(), static_cast<size_t>(std::max(internal_delay, 0)));
return internal_delay >=
static_cast<int>(config_.delay.min_echo_path_delay_blocks);
}
void RenderDelayBufferImpl::SetAudioBufferDelay(size_t delay_ms) {
if (!external_audio_buffer_delay_) {
RTC_LOG(LS_WARNING)
<< "Receiving a first reported externally buffer delay of " << delay_ms
<< " ms.";
}
// Convert delay from milliseconds to blocks (rounded down).
external_audio_buffer_delay_ = delay_ms / 4;
}
// Maps the externally computed delay to the delay used internally.
int RenderDelayBufferImpl::MapExternalDelayToInternalDelay(
size_t external_delay_blocks) const {
const int latency = BufferLatency(low_rate_);
RTC_DCHECK_LT(0, sub_block_size_);
RTC_DCHECK_EQ(0, latency % sub_block_size_);
int latency_blocks = latency / sub_block_size_;
return latency_blocks + static_cast<int>(external_delay_blocks) -
DelayEstimatorOffset(config_);
}
// Maps the internally used delay to the delay used externally.
int RenderDelayBufferImpl::MapInternalDelayToExternalDelay() const {
const int latency = BufferLatency(low_rate_);
int latency_blocks = latency / sub_block_size_;
int internal_delay = spectra_.read >= spectra_.write
? spectra_.read - spectra_.write
: spectra_.size + spectra_.read - spectra_.write;
return internal_delay - latency_blocks + DelayEstimatorOffset(config_);
}
// Set the read indices according to the delay.
void RenderDelayBufferImpl::ApplyDelay(int delay) {
RTC_LOG(LS_WARNING) << "Applying internal 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);
}
// Inserts a block into the render buffers.
void RenderDelayBufferImpl::InsertBlock(
const std::vector<std::vector<float>>& block,
int previous_write) {
auto& b = blocks_;
auto& lr = low_rate_;
auto& ds = render_ds_;
auto& f = ffts_;
auto& s = spectra_;
RTC_DCHECK_EQ(block.size(), b.buffer[b.write].size());
for (size_t k = 0; k < block.size(); ++k) {
RTC_DCHECK_EQ(block[k].size(), b.buffer[b.write][k].size());
std::copy(block[k].begin(), block[k].end(), b.buffer[b.write][k].begin());
}
data_dumper_->DumpWav("aec3_render_decimator_input", block[0].size(),
block[0].data(), 16000, 1);
render_decimator_.Decimate(block[0], 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);
fft_.PaddedFft(block[0], b.buffer[previous_write][0], &f.buffer[f.write]);
f.buffer[f.write].Spectrum(optimization_, s.buffer[s.write]);
}
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;
}
} // namespace
int RenderDelayBuffer::RenderDelayBuffer::DelayEstimatorOffset(
const EchoCanceller3Config& config) {
return config.delay.api_call_jitter_blocks * 2;
}
RenderDelayBuffer* RenderDelayBuffer::Create(const EchoCanceller3Config& config,
size_t num_bands) {
return new RenderDelayBufferImpl(config, num_bands);
}
} // namespace webrtc