blob: ad5133b72fc016a7635c10adc9d7b5fff8a21d2a [file] [log] [blame]
* Copyright (c) 2016 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 "webrtc/modules/congestion_controller/median_slope_estimator.h"
#include <algorithm>
#include <vector>
#include "webrtc/modules/remote_bitrate_estimator/include/bwe_defines.h"
#include "webrtc/modules/remote_bitrate_estimator/test/bwe_test_logging.h"
#include "webrtc/rtc_base/logging.h"
namespace webrtc {
constexpr unsigned int kDeltaCounterMax = 1000;
MedianSlopeEstimator::MedianSlopeEstimator(size_t window_size,
double threshold_gain)
: window_size_(window_size),
trendline_(0) {}
MedianSlopeEstimator::~MedianSlopeEstimator() {}
MedianSlopeEstimator::DelayInfo::DelayInfo(int64_t time,
double delay,
size_t slope_count)
: time(time), delay(delay) {
MedianSlopeEstimator::DelayInfo::~DelayInfo() = default;
void MedianSlopeEstimator::Update(double recv_delta_ms,
double send_delta_ms,
int64_t arrival_time_ms) {
const double delta_ms = recv_delta_ms - send_delta_ms;
if (num_of_deltas_ > kDeltaCounterMax)
num_of_deltas_ = kDeltaCounterMax;
accumulated_delay_ += delta_ms;
BWE_TEST_LOGGING_PLOT(1, "accumulated_delay_ms", arrival_time_ms,
// If the window is full, remove the |window_size_| - 1 slopes that belong to
// the oldest point.
if (delay_hist_.size() == window_size_) {
for (double slope : delay_hist_.front().slopes) {
const bool success = median_filter_.Erase(slope);
// Add |window_size_| - 1 new slopes.
for (auto& old_delay : delay_hist_) {
if (arrival_time_ms - old_delay.time != 0) {
// The C99 standard explicitly states that casts and assignments must
// perform the associated conversions. This means that |slope| will be
// a 64-bit double even if the division is computed using, e.g., 80-bit
// extended precision. I believe this also holds in C++ even though the
// C++11 standard isn't as explicit. Furthermore, there are good reasons
// to believe that compilers couldn't perform optimizations that break
// this assumption even if they wanted to.
double slope = (accumulated_delay_ - old_delay.delay) /
static_cast<double>(arrival_time_ms - old_delay.time);
// We want to avoid issues with different rounding mode / precision
// which we might get if we recomputed the slope when we remove it.
delay_hist_.emplace_back(arrival_time_ms, accumulated_delay_,
window_size_ - 1);
// Recompute the median slope.
if (delay_hist_.size() == window_size_)
trendline_ = median_filter_.GetPercentileValue();
BWE_TEST_LOGGING_PLOT(1, "trendline_slope", arrival_time_ms, trendline_);
} // namespace webrtc