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/*
* Copyright 2017 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_BITRATEALLOCATIONSTRATEGY_H_
#define RTC_BASE_BITRATEALLOCATIONSTRATEGY_H_
#include <map>
#include <memory>
#include <string>
#include <vector>
#include "api/array_view.h"
#include "rtc_base/checks.h"
namespace rtc {
// Pluggable strategy allows configuration of bitrate allocation per media
// track.
//
// The strategy should provide allocation for every track passed with
// track_configs in AllocateBitrates. The allocations are constrained by
// max_bitrate_bps, min_bitrate_bps defining the track supported range and
// enforce_min_bitrate indicating if the track my be paused by allocating 0
// bitrate.
class BitrateAllocationStrategy {
public:
struct TrackConfig {
TrackConfig(uint32_t min_bitrate_bps,
uint32_t max_bitrate_bps,
bool enforce_min_bitrate,
std::string track_id)
: min_bitrate_bps(min_bitrate_bps),
max_bitrate_bps(max_bitrate_bps),
enforce_min_bitrate(enforce_min_bitrate),
track_id(track_id) {}
TrackConfig(const TrackConfig& track_config) = default;
virtual ~TrackConfig() = default;
TrackConfig() {}
// Minimum bitrate supported by track.
uint32_t min_bitrate_bps;
// Maximum bitrate supported by track.
uint32_t max_bitrate_bps;
// True means track may not be paused by allocating 0 bitrate.
bool enforce_min_bitrate;
// MediaStreamTrack ID as defined by application. May be empty.
std::string track_id;
};
static std::vector<uint32_t> SetAllBitratesToMinimum(
const ArrayView<const TrackConfig*> track_configs);
static std::vector<uint32_t> DistributeBitratesEvenly(
const ArrayView<const TrackConfig*> track_configs,
uint32_t available_bitrate);
// Strategy is expected to allocate all available_bitrate up to the sum of
// max_bitrate_bps of all tracks. If available_bitrate is less than the sum of
// min_bitrate_bps of all tracks, tracks having enforce_min_bitrate set to
// false may get 0 allocation and are suppoused to pause, tracks with
// enforce_min_bitrate set to true are expecting to get min_bitrate_bps.
//
// If the strategy will allocate more than available_bitrate it may cause
// overuse of the currently available network capacity and may cause increase
// in RTT and packet loss. Allocating less than available bitrate may cause
// available_bitrate decrease.
virtual std::vector<uint32_t> AllocateBitrates(
uint32_t available_bitrate,
const ArrayView<const TrackConfig*> track_configs) = 0;
virtual ~BitrateAllocationStrategy() = default;
};
// Simple allocation strategy giving priority to audio until
// sufficient_audio_bitrate is reached. Bitrate is distributed evenly between
// the tracks after sufficient_audio_bitrate is reached. This implementation
// does not pause tracks even if enforce_min_bitrate is false.
class AudioPriorityBitrateAllocationStrategy
: public BitrateAllocationStrategy {
public:
AudioPriorityBitrateAllocationStrategy(std::string audio_track_id,
uint32_t sufficient_audio_bitrate);
std::vector<uint32_t> AllocateBitrates(
uint32_t available_bitrate,
const ArrayView<const TrackConfig*> track_configs) override;
private:
std::string audio_track_id_;
uint32_t sufficient_audio_bitrate_;
};
} // namespace rtc
#endif // RTC_BASE_BITRATEALLOCATIONSTRATEGY_H_
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