modules/video_coding/codec_timer.h

/*
 *  Copyright (c) 2011 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 MODULES_VIDEO_CODING_CODEC_TIMER_H_
#define MODULES_VIDEO_CODING_CODEC_TIMER_H_

#include <queue>

#include "modules/include/module_common_types.h"
#include "rtc_base/numerics/percentile_filter.h"
#include "typedefs.h"  // NOLINT(build/include)

namespace webrtc {

class VCMCodecTimer {
 public:
  VCMCodecTimer();

  // Add a new decode time to the filter.
  void AddTiming(int64_t new_decode_time_ms, int64_t now_ms);

  // Get the required decode time in ms. It is the 95th percentile observed
  // decode time within a time window.
  int64_t RequiredDecodeTimeMs() const;

 private:
  struct Sample {
    Sample(int64_t decode_time_ms, int64_t sample_time_ms);
    int64_t decode_time_ms;
    int64_t sample_time_ms;
  };

  // The number of samples ignored so far.
  int ignored_sample_count_;
  // Queue with history of latest decode time values.
  std::queue<Sample> history_;
  // |filter_| contains the same values as |history_|, but in a data structure
  // that allows efficient retrieval of the percentile value.
  PercentileFilter<int64_t> filter_;
};

}  // namespace webrtc

#endif  // MODULES_VIDEO_CODING_CODEC_TIMER_H_