video/adaptation/quality_scaler_resource.cc

/*
 *  Copyright 2020 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 "video/adaptation/quality_scaler_resource.h"

#include <utility>

#include "rtc_base/experiments/balanced_degradation_settings.h"
#include "rtc_base/ref_counted_object.h"
#include "rtc_base/task_utils/to_queued_task.h"
#include "rtc_base/time_utils.h"

namespace webrtc {

namespace {

const int64_t kUnderuseDueToDisabledCooldownMs = 1000;

}  // namespace

// static
rtc::scoped_refptr<QualityScalerResource> QualityScalerResource::Create(
    DegradationPreferenceProvider* degradation_preference_provider) {
  return new rtc::RefCountedObject<QualityScalerResource>(
      degradation_preference_provider);
}

QualityScalerResource::QualityScalerResource(
    DegradationPreferenceProvider* degradation_preference_provider)
    : VideoStreamEncoderResource("QualityScalerResource"),
      quality_scaler_(nullptr),
      last_underuse_due_to_disabled_timestamp_ms_(absl::nullopt),
      degradation_preference_provider_(degradation_preference_provider) {
  RTC_CHECK(degradation_preference_provider_);
}

QualityScalerResource::~QualityScalerResource() {
  RTC_DCHECK(!quality_scaler_);
}

bool QualityScalerResource::is_started() const {
  RTC_DCHECK_RUN_ON(encoder_queue());
  return quality_scaler_.get();
}

void QualityScalerResource::StartCheckForOveruse(
    VideoEncoder::QpThresholds qp_thresholds) {
  RTC_DCHECK_RUN_ON(encoder_queue());
  RTC_DCHECK(!is_started());
  quality_scaler_ =
      std::make_unique<QualityScaler>(this, std::move(qp_thresholds));
}

void QualityScalerResource::StopCheckForOveruse() {
  RTC_DCHECK_RUN_ON(encoder_queue());
  // Ensure we have no pending callbacks. This makes it safe to destroy the
  // QualityScaler and even task queues with tasks in-flight.
  quality_scaler_.reset();
}

void QualityScalerResource::SetQpThresholds(
    VideoEncoder::QpThresholds qp_thresholds) {
  RTC_DCHECK_RUN_ON(encoder_queue());
  RTC_DCHECK(is_started());
  quality_scaler_->SetQpThresholds(std::move(qp_thresholds));
}

bool QualityScalerResource::QpFastFilterLow() {
  RTC_DCHECK_RUN_ON(encoder_queue());
  RTC_DCHECK(is_started());
  return quality_scaler_->QpFastFilterLow();
}

void QualityScalerResource::OnEncodeCompleted(const EncodedImage& encoded_image,
                                              int64_t time_sent_in_us) {
  RTC_DCHECK_RUN_ON(encoder_queue());
  if (quality_scaler_ && encoded_image.qp_ >= 0) {
    quality_scaler_->ReportQp(encoded_image.qp_, time_sent_in_us);
  } else if (!quality_scaler_) {
    // Reference counting guarantees that this object is still alive by the time
    // the task is executed.
    // TODO(webrtc:11553): this is a workaround to ensure that all quality
    // scaler imposed limitations are removed once qualty scaler is disabled
    // mid call.
    // Instead it should be done at a higher layer in the same way for all
    // resources.
    int64_t timestamp_ms = rtc::TimeMillis();
    if (!last_underuse_due_to_disabled_timestamp_ms_.has_value() ||
        timestamp_ms - last_underuse_due_to_disabled_timestamp_ms_.value() >=
            kUnderuseDueToDisabledCooldownMs) {
      last_underuse_due_to_disabled_timestamp_ms_ = timestamp_ms;
      OnResourceUsageStateMeasured(ResourceUsageState::kUnderuse);
    }
  }
}

void QualityScalerResource::OnFrameDropped(
    EncodedImageCallback::DropReason reason) {
  RTC_DCHECK_RUN_ON(encoder_queue());
  if (!quality_scaler_)
    return;
  switch (reason) {
    case EncodedImageCallback::DropReason::kDroppedByMediaOptimizations:
      quality_scaler_->ReportDroppedFrameByMediaOpt();
      break;
    case EncodedImageCallback::DropReason::kDroppedByEncoder:
      quality_scaler_->ReportDroppedFrameByEncoder();
      break;
  }
}

void QualityScalerResource::OnReportQpUsageHigh() {
  OnResourceUsageStateMeasured(ResourceUsageState::kOveruse);
}

void QualityScalerResource::OnReportQpUsageLow() {
  OnResourceUsageStateMeasured(ResourceUsageState::kUnderuse);
}

}  // namespace webrtc