rtc_base/experiments/quality_scaling_experiment.h

/*
 *  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.
 */
#ifndef RTC_BASE_EXPERIMENTS_QUALITY_SCALING_EXPERIMENT_H_
#define RTC_BASE_EXPERIMENTS_QUALITY_SCALING_EXPERIMENT_H_

#include <optional>

#include "api/field_trials_view.h"
#include "api/video_codecs/video_encoder.h"

namespace webrtc {
class QualityScalingExperiment {
 public:
  struct Settings {
    int vp8_low;       // VP8: low QP threshold.
    int vp8_high;      // VP8: high QP threshold.
    int vp9_low;       // VP9: low QP threshold.
    int vp9_high;      // VP9: high QP threshold.
    int h264_low;      // H264: low QP threshold.
    int h264_high;     // H264: high QP threshold.
    int generic_low;   // Generic: low QP threshold.
    int generic_high;  // Generic: high QP threshold.
    float alpha_high;  // `alpha_` for ExpFilter used when checking high QP.
    float alpha_low;   // `alpha_` for ExpFilter used when checking low QP.
    int drop;          // >0 sets `use_all_drop_reasons` to true.
  };

  // Used by QualityScaler.
  struct Config {
    float alpha_high = 0.9995f;
    float alpha_low = 0.9999f;
    // If set, all type of dropped frames are used.
    // Otherwise only dropped frames by MediaOptimization are used.
    bool use_all_drop_reasons = false;
  };

  // Returns true if the experiment is enabled.
  static bool Enabled(const FieldTrialsView& field_trials);

  // Returns settings from field trial.
  static std::optional<Settings> ParseSettings(
      const FieldTrialsView& field_trials);

  // Returns QpThresholds for the `codec_type`.
  static std::optional<VideoEncoder::QpThresholds> GetQpThresholds(
      VideoCodecType codec_type,
      const FieldTrialsView& field_trials);

  // Returns parsed values. If the parsing fails, default values are returned.
  static Config GetConfig(const FieldTrialsView& field_trials);
};

}  // namespace webrtc

#endif  // RTC_BASE_EXPERIMENTS_QUALITY_SCALING_EXPERIMENT_H_