115 lines
3.5 KiB
C++
115 lines
3.5 KiB
C++
/*
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* Copyright 2019 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 "rtc_base/experiments/min_video_bitrate_experiment.h"
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#include <string>
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#include "rtc_base/checks.h"
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#include "rtc_base/experiments/field_trial_parser.h"
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#include "rtc_base/logging.h"
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#include "system_wrappers/include/field_trial.h"
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namespace webrtc {
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const int kDefaultMinVideoBitrateBps = 30000;
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namespace {
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const char kForcedFallbackFieldTrial[] =
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"WebRTC-VP8-Forced-Fallback-Encoder-v2";
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const char kMinVideoBitrateExperiment[] = "WebRTC-Video-MinVideoBitrate";
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absl::optional<int> GetFallbackMinBpsFromFieldTrial(VideoCodecType type) {
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if (type != kVideoCodecVP8) {
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return absl::nullopt;
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}
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if (!webrtc::field_trial::IsEnabled(kForcedFallbackFieldTrial)) {
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return absl::nullopt;
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}
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const std::string group =
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webrtc::field_trial::FindFullName(kForcedFallbackFieldTrial);
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if (group.empty()) {
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return absl::nullopt;
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}
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int min_pixels; // Ignored.
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int max_pixels; // Ignored.
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int min_bps;
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if (sscanf(group.c_str(), "Enabled-%d,%d,%d", &min_pixels, &max_pixels,
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&min_bps) != 3) {
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return absl::nullopt;
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}
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if (min_bps <= 0) {
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return absl::nullopt;
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}
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return min_bps;
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}
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} // namespace
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absl::optional<DataRate> GetExperimentalMinVideoBitrate(VideoCodecType type) {
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const absl::optional<int> fallback_min_bitrate_bps =
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GetFallbackMinBpsFromFieldTrial(type);
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if (fallback_min_bitrate_bps) {
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return DataRate::BitsPerSec(*fallback_min_bitrate_bps);
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}
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if (webrtc::field_trial::IsEnabled(kMinVideoBitrateExperiment)) {
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webrtc::FieldTrialFlag enabled("Enabled");
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// Backwards-compatibility with an old experiment - a generic minimum which,
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// if set, applies to all codecs.
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webrtc::FieldTrialOptional<webrtc::DataRate> min_video_bitrate("br");
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// New experiment - per-codec minimum bitrate.
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webrtc::FieldTrialOptional<webrtc::DataRate> min_bitrate_vp8("vp8_br");
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webrtc::FieldTrialOptional<webrtc::DataRate> min_bitrate_vp9("vp9_br");
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webrtc::FieldTrialOptional<webrtc::DataRate> min_bitrate_av1("av1_br");
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webrtc::FieldTrialOptional<webrtc::DataRate> min_bitrate_h264("h264_br");
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webrtc::ParseFieldTrial(
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{&enabled, &min_video_bitrate, &min_bitrate_vp8, &min_bitrate_vp9,
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&min_bitrate_av1, &min_bitrate_h264},
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webrtc::field_trial::FindFullName(kMinVideoBitrateExperiment));
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if (min_video_bitrate) {
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if (min_bitrate_vp8 || min_bitrate_vp9 || min_bitrate_av1 ||
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min_bitrate_h264) {
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// "br" is mutually-exclusive with the other configuration possibilites.
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RTC_LOG(LS_WARNING) << "Self-contradictory experiment config.";
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}
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return *min_video_bitrate;
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}
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switch (type) {
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case kVideoCodecVP8:
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return min_bitrate_vp8.GetOptional();
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case kVideoCodecVP9:
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return min_bitrate_vp9.GetOptional();
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case kVideoCodecAV1:
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return min_bitrate_av1.GetOptional();
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case kVideoCodecH264:
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return min_bitrate_h264.GetOptional();
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case kVideoCodecGeneric:
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case kVideoCodecMultiplex:
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return absl::nullopt;
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}
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RTC_NOTREACHED();
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}
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return absl::nullopt;
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}
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} // namespace webrtc
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