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/*
* Copyright 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 "rtc_base/experiments/quality_scaling_experiment.h"
#include <stdio.h>
#include <string>
#include "absl/strings/match.h"
#include "api/field_trials_view.h"
#include "api/transport/field_trial_based_config.h"
#include "rtc_base/logging.h"
namespace webrtc {
namespace {
constexpr char kFieldTrial[] = "WebRTC-Video-QualityScaling";
constexpr int kMinQp = 1;
constexpr int kMaxVp8Qp = 127;
constexpr int kMaxVp9Qp = 255;
constexpr int kMaxH264Qp = 51;
constexpr int kMaxGenericQp = 255;
#if !defined(WEBRTC_IOS)
constexpr char kDefaultQualityScalingSetttings[] =
"Enabled-29,95,149,205,24,37,26,36,0.9995,0.9999,1";
#endif
absl::optional<VideoEncoder::QpThresholds> GetThresholds(int low,
int high,
int max) {
if (low < kMinQp || high > max || high < low)
return absl::nullopt;
RTC_LOG(LS_INFO) << "QP thresholds: low: " << low << ", high: " << high;
return absl::optional<VideoEncoder::QpThresholds>(
VideoEncoder::QpThresholds(low, high));
}
} // namespace
bool QualityScalingExperiment::Enabled(const FieldTrialsView& field_trials) {
#if defined(WEBRTC_IOS)
return absl::StartsWith(field_trials.Lookup(kFieldTrial), "Enabled");
#else
return !absl::StartsWith(field_trials.Lookup(kFieldTrial), "Disabled");
#endif
}
absl::optional<QualityScalingExperiment::Settings>
QualityScalingExperiment::ParseSettings(const FieldTrialsView& field_trials) {
std::string group = field_trials.Lookup(kFieldTrial);
// TODO(http://crbug.com/webrtc/12401): Completely remove the experiment code
// after few releases.
#if !defined(WEBRTC_IOS)
if (group.empty())
group = kDefaultQualityScalingSetttings;
#endif
Settings s;
if (sscanf(group.c_str(), "Enabled-%d,%d,%d,%d,%d,%d,%d,%d,%f,%f,%d",
&s.vp8_low, &s.vp8_high, &s.vp9_low, &s.vp9_high, &s.h264_low,
&s.h264_high, &s.generic_low, &s.generic_high, &s.alpha_high,
&s.alpha_low, &s.drop) != 11) {
RTC_LOG(LS_WARNING) << "Invalid number of parameters provided.";
return absl::nullopt;
}
return s;
}
absl::optional<VideoEncoder::QpThresholds>
QualityScalingExperiment::GetQpThresholds(VideoCodecType codec_type,
const FieldTrialsView& field_trials) {
const auto settings = ParseSettings(field_trials);
if (!settings)
return absl::nullopt;
switch (codec_type) {
case kVideoCodecVP8:
return GetThresholds(settings->vp8_low, settings->vp8_high, kMaxVp8Qp);
case kVideoCodecVP9:
return GetThresholds(settings->vp9_low, settings->vp9_high, kMaxVp9Qp);
case kVideoCodecH265:
// TODO(bugs.webrtc.org/13485): Use H264 QP thresholds for now.
case kVideoCodecH264:
return GetThresholds(settings->h264_low, settings->h264_high, kMaxH264Qp);
case kVideoCodecGeneric:
return GetThresholds(settings->generic_low, settings->generic_high,
kMaxGenericQp);
default:
return absl::nullopt;
}
}
QualityScalingExperiment::Config QualityScalingExperiment::GetConfig(
const FieldTrialsView& field_trials) {
const auto settings = ParseSettings(field_trials);
if (!settings)
return Config();
Config config;
config.use_all_drop_reasons = settings->drop > 0;
if (settings->alpha_high < 0 || settings->alpha_low < settings->alpha_high) {
RTC_LOG(LS_WARNING) << "Invalid alpha value provided, using default.";
return config;
}
config.alpha_high = settings->alpha_high;
config.alpha_low = settings->alpha_low;
return config;
}
} // namespace webrtc
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