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/*
* Copyright (c) 2021 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/video_coding/utility/bandwidth_quality_scaler.h"
#include <cstdint>
#include <optional>
#include <vector>
#include "api/sequence_checker.h"
#include "api/task_queue/task_queue_base.h"
#include "api/video/video_codec_type.h"
#include "api/video_codecs/video_encoder.h"
#include "rtc_base/checks.h"
#include "rtc_base/experiments/encoder_info_settings.h"
#include "rtc_base/rate_statistics.h"
#include "rtc_base/weak_ptr.h"
namespace webrtc {
namespace {
constexpr int kDefaultMaxWindowSizeMs = 5000;
constexpr float kHigherMaxBitrateTolerationFactor = 0.95;
constexpr float kLowerMinBitrateTolerationFactor = 0.8;
} // namespace
BandwidthQualityScaler::BandwidthQualityScaler(
BandwidthQualityScalerUsageHandlerInterface* handler)
: handler_(handler),
encoded_bitrate_(kDefaultMaxWindowSizeMs, RateStatistics::kBpsScale),
weak_ptr_factory_(this) {
RTC_DCHECK_RUN_ON(&task_checker_);
RTC_DCHECK(handler_ != nullptr);
StartCheckForBitrate();
}
BandwidthQualityScaler::~BandwidthQualityScaler() {
RTC_DCHECK_RUN_ON(&task_checker_);
}
void BandwidthQualityScaler::StartCheckForBitrate() {
RTC_DCHECK_RUN_ON(&task_checker_);
TaskQueueBase::Current()->PostDelayedTask(
[this_weak_ptr = weak_ptr_factory_.GetWeakPtr(), this] {
if (!this_weak_ptr) {
// The caller BandwidthQualityScaler has been deleted.
return;
}
RTC_DCHECK_RUN_ON(&task_checker_);
switch (CheckBitrate()) {
case BandwidthQualityScaler::CheckBitrateResult::kHighBitRate: {
handler_->OnReportUsageBandwidthHigh();
last_frame_size_pixels_.reset();
break;
}
case BandwidthQualityScaler::CheckBitrateResult::kLowBitRate: {
handler_->OnReportUsageBandwidthLow();
last_frame_size_pixels_.reset();
break;
}
case BandwidthQualityScaler::CheckBitrateResult::kNormalBitrate: {
break;
}
case BandwidthQualityScaler::CheckBitrateResult::
kInsufficientSamples: {
break;
}
}
StartCheckForBitrate();
},
kBitrateStateUpdateInterval);
}
void BandwidthQualityScaler::ReportEncodeInfo(int frame_size_bytes,
int64_t time_sent_in_ms,
uint32_t encoded_width,
uint32_t encoded_height) {
RTC_DCHECK_RUN_ON(&task_checker_);
last_time_sent_in_ms_ = time_sent_in_ms;
last_frame_size_pixels_ = encoded_width * encoded_height;
encoded_bitrate_.Update(frame_size_bytes, time_sent_in_ms);
}
void BandwidthQualityScaler::SetResolutionBitrateLimits(
const std::vector<VideoEncoder::ResolutionBitrateLimits>&
resolution_bitrate_limits,
VideoCodecType codec_type) {
if (resolution_bitrate_limits.empty()) {
resolution_bitrate_limits_ =
EncoderInfoSettings::GetDefaultSinglecastBitrateLimitsWhenQpIsUntrusted(
codec_type);
} else {
resolution_bitrate_limits_ = resolution_bitrate_limits;
}
}
BandwidthQualityScaler::CheckBitrateResult
BandwidthQualityScaler::CheckBitrate() {
RTC_DCHECK_RUN_ON(&task_checker_);
if (!last_frame_size_pixels_.has_value() ||
!last_time_sent_in_ms_.has_value()) {
return BandwidthQualityScaler::CheckBitrateResult::kInsufficientSamples;
}
std::optional<int64_t> current_bitrate_bps =
encoded_bitrate_.Rate(last_time_sent_in_ms_.value());
if (!current_bitrate_bps.has_value()) {
// We can't get a valid bitrate due to not enough data points.
return BandwidthQualityScaler::CheckBitrateResult::kInsufficientSamples;
}
std::optional<VideoEncoder::ResolutionBitrateLimits> suitable_bitrate_limit =
EncoderInfoSettings::
GetSinglecastBitrateLimitForResolutionWhenQpIsUntrusted(
last_frame_size_pixels_, resolution_bitrate_limits_);
if (!suitable_bitrate_limit.has_value()) {
return BandwidthQualityScaler::CheckBitrateResult::kInsufficientSamples;
}
// Multiply by toleration factor to solve the frequent adaptation due to
// critical value.
if (current_bitrate_bps > suitable_bitrate_limit->max_bitrate_bps *
kHigherMaxBitrateTolerationFactor) {
return BandwidthQualityScaler::CheckBitrateResult::kLowBitRate;
} else if (current_bitrate_bps <
suitable_bitrate_limit->min_start_bitrate_bps *
kLowerMinBitrateTolerationFactor) {
return BandwidthQualityScaler::CheckBitrateResult::kHighBitRate;
}
return BandwidthQualityScaler::CheckBitrateResult::kNormalBitrate;
}
BandwidthQualityScalerUsageHandlerInterface::
~BandwidthQualityScalerUsageHandlerInterface() {}
} // namespace webrtc
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