blob: a54bd9a5615457f581fef3ad3297ba434fdd701c [file] [log] [blame]
* Copyright (c) 2023 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 <stddef.h>
#include <stdint.h>
#include "absl/types/optional.h"
#include "api/units/data_rate.h"
#include "api/units/data_size.h"
#include "api/units/time_delta.h"
#include "api/units/timestamp.h"
#include "rtc_base/rate_statistics.h"
#include "rtc_base/system/rtc_export.h"
namespace webrtc {
// Class to estimate bitrates over running window.
// Timestamps used in Update(), Rate() and SetWindowSize() must never
// decrease for two consecutive calls.
// This class is thread unsafe.
class RTC_EXPORT BitrateTracker {
// max_window_sizes = Maximum window size for the rate estimation.
// Initial window size is set to this, but may be changed
// to something lower by calling SetWindowSize().
explicit BitrateTracker(TimeDelta max_window_size);
BitrateTracker(const BitrateTracker&) = default;
BitrateTracker(BitrateTracker&&) = default;
BitrateTracker& operator=(const BitrateTracker&) = delete;
BitrateTracker& operator=(BitrateTracker&&) = delete;
~BitrateTracker() = default;
// Resets instance to original state.
void Reset() { impl_.Reset(); }
// Updates bitrate with a new data point, moving averaging window as needed.
void Update(int64_t bytes, Timestamp now);
void Update(DataSize size, Timestamp now) { Update(size.bytes(), now); }
// Returns bitrate, moving averaging window as needed.
// Returns nullopt when bitrate can't be measured.
absl::optional<DataRate> Rate(Timestamp now) const;
// Update the size of the averaging window. The maximum allowed value for
// `window_size` is `max_window_size` as supplied in the constructor.
bool SetWindowSize(TimeDelta window_size, Timestamp now);
RateStatistics impl_;
} // namespace webrtc