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3bdbc84888
Since the pushback controller doesn't strictly adhere to the congestion window, it better belongs together with the congestion controller logic. Also ensuring that it does not override the configured min bitrate. Bug: webrtc:9586 Change-Id: I57dcfc946d470247e66c67adabddaafa3d9d83ad Reviewed-on: https://webrtc-review.googlesource.com/c/105102 Commit-Queue: Sebastian Jansson <srte@webrtc.org> Reviewed-by: Ying Wang <yinwa@webrtc.org> Cr-Commit-Position: refs/heads/master@{#25115}
95 lines
3.5 KiB
C++
95 lines
3.5 KiB
C++
/*
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* Copyright (c) 2018 The WebRTC project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#include <algorithm>
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#include <string>
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#include "modules/congestion_controller/goog_cc/congestion_window_pushback_controller.h"
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#include "rtc_base/checks.h"
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#include "rtc_base/format_macros.h"
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#include "system_wrappers/include/field_trial.h"
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namespace webrtc {
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// When CongestionWindowPushback is enabled, the pacer is oblivious to
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// the congestion window. The relation between outstanding data and
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// the congestion window affects encoder allocations directly.
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// This experiment is build on top of congestion window experiment.
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const char kCongestionPushbackExperiment[] = "WebRTC-CongestionWindowPushback";
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const uint32_t kDefaultMinPushbackTargetBitrateBps = 30000;
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bool ReadCongestionWindowPushbackExperimentParameter(
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uint32_t* min_pushback_target_bitrate_bps) {
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RTC_DCHECK(min_pushback_target_bitrate_bps);
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std::string experiment_string =
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webrtc::field_trial::FindFullName(kCongestionPushbackExperiment);
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int parsed_values = sscanf(experiment_string.c_str(), "Enabled-%" PRIu32,
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min_pushback_target_bitrate_bps);
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if (parsed_values == 1) {
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RTC_CHECK_GE(*min_pushback_target_bitrate_bps, 0)
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<< "Min pushback target bitrate must be greater than or equal to 0.";
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return true;
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}
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return false;
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}
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CongestionWindowPushbackController::CongestionWindowPushbackController() {
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if (!ReadCongestionWindowPushbackExperimentParameter(
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&min_pushback_target_bitrate_bps_)) {
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min_pushback_target_bitrate_bps_ = kDefaultMinPushbackTargetBitrateBps;
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}
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}
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void CongestionWindowPushbackController::UpdateOutstandingData(
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size_t outstanding_bytes) {
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outstanding_bytes_ = outstanding_bytes;
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}
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void CongestionWindowPushbackController::UpdateMaxOutstandingData(
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size_t max_outstanding_bytes) {
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DataSize data_window = DataSize::bytes(max_outstanding_bytes);
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if (current_data_window_) {
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data_window = (data_window + current_data_window_.value()) / 2;
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}
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current_data_window_ = data_window;
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}
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void CongestionWindowPushbackController::SetDataWindow(DataSize data_window) {
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current_data_window_ = data_window;
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}
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uint32_t CongestionWindowPushbackController::UpdateTargetBitrate(
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uint32_t bitrate_bps) {
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if (!current_data_window_ || current_data_window_->IsZero())
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return bitrate_bps;
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double fill_ratio =
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outstanding_bytes_ / static_cast<double>(current_data_window_->bytes());
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if (fill_ratio > 1.5) {
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encoding_rate_ratio_ *= 0.9;
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} else if (fill_ratio > 1) {
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encoding_rate_ratio_ *= 0.95;
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} else if (fill_ratio < 0.1) {
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encoding_rate_ratio_ = 1.0;
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} else {
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encoding_rate_ratio_ *= 1.05;
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encoding_rate_ratio_ = std::min(encoding_rate_ratio_, 1.0);
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}
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uint32_t adjusted_target_bitrate_bps =
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static_cast<uint32_t>(bitrate_bps * encoding_rate_ratio_);
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// Do not adjust below the minimum pushback bitrate but do obey if the
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// original estimate is below it.
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bitrate_bps = adjusted_target_bitrate_bps < min_pushback_target_bitrate_bps_
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? std::min(bitrate_bps, min_pushback_target_bitrate_bps_)
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: adjusted_target_bitrate_bps;
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return bitrate_bps;
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}
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} // namespace webrtc
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