call/bitrate_allocator.h - src/ - Git at Google

 /*
  *  Copyright (c) 2015 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 CALL_BITRATE_ALLOCATOR_H_
 #define CALL_BITRATE_ALLOCATOR_H_

 #include <stdint.h>

 #include <map>
 #include <memory>
 #include <string>
 #include <utility>
 #include <vector>

 #include "api/call/bitrate_allocation.h"
 #include "api/transport/network_types.h"
 #include "rtc_base/synchronization/sequence_checker.h"

 namespace webrtc {

 class Clock;

 // Used by all send streams with adaptive bitrate, to get the currently
 // allocated bitrate for the send stream. The current network properties are
 // given at the same time, to let the send stream decide about possible loss
 // protection.
 class BitrateAllocatorObserver {
  public:
   // Returns the amount of protection used by the BitrateAllocatorObserver
   // implementation, as bitrate in bps.
   virtual uint32_t OnBitrateUpdated(BitrateAllocationUpdate update) = 0;

  protected:
   virtual ~BitrateAllocatorObserver() {}
 };

 // Struct describing parameters for how a media stream should get bitrate
 // allocated to it.

 struct MediaStreamAllocationConfig {
   // Minimum bitrate supported by track. 0 equals no min bitrate.
   uint32_t min_bitrate_bps;
   // Maximum bitrate supported by track. 0 equals no max bitrate.
   uint32_t max_bitrate_bps;
   uint32_t pad_up_bitrate_bps;
   int64_t priority_bitrate_bps;
   // True means track may not be paused by allocating 0 bitrate will allocate at
   // least |min_bitrate_bps| for this observer, even if the BWE is too low,
   // false will allocate 0 to the observer if BWE doesn't allow
   // |min_bitrate_bps|.
   bool enforce_min_bitrate;
   // The amount of bitrate allocated to this observer relative to all other
   // observers. If an observer has twice the bitrate_priority of other
   // observers, it should be allocated twice the bitrate above its min.
   double bitrate_priority;
 };

 // Interface used for mocking
 class BitrateAllocatorInterface {
  public:
   virtual void AddObserver(BitrateAllocatorObserver* observer,
                            MediaStreamAllocationConfig config) = 0;
   virtual void RemoveObserver(BitrateAllocatorObserver* observer) = 0;
   virtual int GetStartBitrate(BitrateAllocatorObserver* observer) const = 0;

  protected:
   virtual ~BitrateAllocatorInterface() = default;
 };

 // Usage: this class will register multiple RtcpBitrateObserver's one at each
 // RTCP module. It will aggregate the results and run one bandwidth estimation
 // and push the result to the encoders via BitrateAllocatorObserver(s).
 class BitrateAllocator : public BitrateAllocatorInterface {
  public:
   // Used to get notified when send stream limits such as the minimum send
   // bitrate and max padding bitrate is changed.
   class LimitObserver {
    public:
     virtual void OnAllocationLimitsChanged(BitrateAllocationLimits limits) = 0;

    protected:
     virtual ~LimitObserver() = default;
   };

   explicit BitrateAllocator(LimitObserver* limit_observer);
   ~BitrateAllocator() override;

   void UpdateStartRate(uint32_t start_rate_bps);

   // Allocate target_bitrate across the registered BitrateAllocatorObservers.
   void OnNetworkEstimateChanged(TargetTransferRate msg);

   // Set the configuration used by the bandwidth management.
   // |observer| updates bitrates if already in use.
   // |config| is the configuration to use for allocation.
   // Note that |observer|->OnBitrateUpdated() will be called
   // within the scope of this method with the current rtt, fraction_loss and
   // available bitrate and that the bitrate in OnBitrateUpdated will be zero if
   // the |observer| is currently not allowed to send data.
   void AddObserver(BitrateAllocatorObserver* observer,
                    MediaStreamAllocationConfig config) override;

   // Removes a previously added observer, but will not trigger a new bitrate
   // allocation.
   void RemoveObserver(BitrateAllocatorObserver* observer) override;

   // Returns initial bitrate allocated for |observer|. If |observer| is not in
   // the list of added observers, a best guess is returned.
   int GetStartBitrate(BitrateAllocatorObserver* observer) const override;

  private:
   struct AllocatableTrack {
     AllocatableTrack(BitrateAllocatorObserver* observer,
                      MediaStreamAllocationConfig allocation_config)
         : observer(observer),
           config(allocation_config),
           allocated_bitrate_bps(-1),
           media_ratio(1.0) {}
     BitrateAllocatorObserver* observer;
     MediaStreamAllocationConfig config;
     int64_t allocated_bitrate_bps;
     double media_ratio;  // Part of the total bitrate used for media [0.0, 1.0].

     uint32_t LastAllocatedBitrate() const;
     // The minimum bitrate required by this observer, including
     // enable-hysteresis if the observer is in a paused state.
     uint32_t MinBitrateWithHysteresis() const;
   };

   // Calculates the minimum requested send bitrate and max padding bitrate and
   // calls LimitObserver::OnAllocationLimitsChanged.
   void UpdateAllocationLimits() RTC_RUN_ON(&sequenced_checker_);

   typedef std::multimap<uint32_t, const AllocatableTrack*> ObserverSortingMap;
   typedef std::map<BitrateAllocatorObserver*, int> ObserverAllocation;

   ObserverAllocation AllocateBitrates(uint32_t bitrate) const
       RTC_RUN_ON(&sequenced_checker_);

   // Allocates zero bitrate to all observers.
   ObserverAllocation ZeroRateAllocation() const RTC_RUN_ON(&sequenced_checker_);
   // Allocates bitrate to observers when there isn't enough to allocate the
   // minimum to all observers.
   ObserverAllocation LowRateAllocation(uint32_t bitrate) const
       RTC_RUN_ON(&sequenced_checker_);
   // Allocates bitrate to all observers when the available bandwidth is enough
   // to allocate the minimum to all observers but not enough to allocate the
   // max bitrate of each observer.
   ObserverAllocation NormalRateAllocation(uint32_t bitrate,
                                           uint32_t sum_min_bitrates) const
       RTC_RUN_ON(&sequenced_checker_);
   // Allocates bitrate to observers when there is enough available bandwidth
   // for all observers to be allocated their max bitrate.
   ObserverAllocation MaxRateAllocation(uint32_t bitrate,
                                        uint32_t sum_max_bitrates) const
       RTC_RUN_ON(&sequenced_checker_);

   // Splits |bitrate| evenly to observers already in |allocation|.
   // |include_zero_allocations| decides if zero allocations should be part of
   // the distribution or not. The allowed max bitrate is |max_multiplier| x
   // observer max bitrate.
   void DistributeBitrateEvenly(uint32_t bitrate,
                                bool include_zero_allocations,
                                int max_multiplier,
                                ObserverAllocation* allocation) const
       RTC_RUN_ON(&sequenced_checker_);
   bool EnoughBitrateForAllObservers(uint32_t bitrate,
                                     uint32_t sum_min_bitrates) const
       RTC_RUN_ON(&sequenced_checker_);

   // From the available |bitrate|, each observer will be allocated a
   // proportional amount based upon its bitrate priority. If that amount is
   // more than the observer's capacity, it will be allocated its capacity, and
   // the excess bitrate is still allocated proportionally to other observers.
   // Allocating the proportional amount means an observer with twice the
   // bitrate_priority of another will be allocated twice the bitrate.
   void DistributeBitrateRelatively(
       uint32_t bitrate,
       const ObserverAllocation& observers_capacities,
       ObserverAllocation* allocation) const RTC_RUN_ON(&sequenced_checker_);

   // Allow packets to be transmitted in up to 2 times max video bitrate if the
   // bandwidth estimate allows it.
   // TODO(bugs.webrtc.org/8541): May be worth to refactor to keep this logic in
   // video send stream.
   static uint8_t GetTransmissionMaxBitrateMultiplier();

   SequenceChecker sequenced_checker_;
   LimitObserver* const limit_observer_ RTC_GUARDED_BY(&sequenced_checker_);
   // Stored in a list to keep track of the insertion order.
   std::vector<AllocatableTrack> allocatable_tracks_
       RTC_GUARDED_BY(&sequenced_checker_);
   uint32_t last_target_bps_ RTC_GUARDED_BY(&sequenced_checker_);
   uint32_t last_stable_target_bps_ RTC_GUARDED_BY(&sequenced_checker_);
   uint32_t last_non_zero_bitrate_bps_ RTC_GUARDED_BY(&sequenced_checker_);
   uint8_t last_fraction_loss_ RTC_GUARDED_BY(&sequenced_checker_);
   int64_t last_rtt_ RTC_GUARDED_BY(&sequenced_checker_);
   int64_t last_bwe_period_ms_ RTC_GUARDED_BY(&sequenced_checker_);
   // Number of mute events based on too low BWE, not network up/down.
   int num_pause_events_ RTC_GUARDED_BY(&sequenced_checker_);
   int64_t last_bwe_log_time_ RTC_GUARDED_BY(&sequenced_checker_);
   BitrateAllocationLimits current_limits_ RTC_GUARDED_BY(&sequenced_checker_);
   const uint8_t transmission_max_bitrate_multiplier_;
 };

 }  // namespace webrtc
 #endif  // CALL_BITRATE_ALLOCATOR_H_
	/*
	* Copyright (c) 2015 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 CALL_BITRATE_ALLOCATOR_H_
	#define CALL_BITRATE_ALLOCATOR_H_

	#include <stdint.h>

	#include <map>
	#include <memory>
	#include <string>
	#include <utility>
	#include <vector>

	#include "api/call/bitrate_allocation.h"
	#include "api/transport/network_types.h"
	#include "rtc_base/synchronization/sequence_checker.h"

	namespace webrtc {

	class Clock;

	// Used by all send streams with adaptive bitrate, to get the currently
	// allocated bitrate for the send stream. The current network properties are
	// given at the same time, to let the send stream decide about possible loss
	// protection.
	class BitrateAllocatorObserver {
	public:
	// Returns the amount of protection used by the BitrateAllocatorObserver
	// implementation, as bitrate in bps.
	virtual uint32_t OnBitrateUpdated(BitrateAllocationUpdate update) = 0;

	protected:
	virtual ~BitrateAllocatorObserver() {}
	};

	// Struct describing parameters for how a media stream should get bitrate
	// allocated to it.

	struct MediaStreamAllocationConfig {
	// Minimum bitrate supported by track. 0 equals no min bitrate.
	uint32_t min_bitrate_bps;
	// Maximum bitrate supported by track. 0 equals no max bitrate.
	uint32_t max_bitrate_bps;
	uint32_t pad_up_bitrate_bps;
	int64_t priority_bitrate_bps;
	// True means track may not be paused by allocating 0 bitrate will allocate at
	// least \|min_bitrate_bps\| for this observer, even if the BWE is too low,
	// false will allocate 0 to the observer if BWE doesn't allow
	// \|min_bitrate_bps\|.
	bool enforce_min_bitrate;
	// The amount of bitrate allocated to this observer relative to all other
	// observers. If an observer has twice the bitrate_priority of other
	// observers, it should be allocated twice the bitrate above its min.
	double bitrate_priority;
	};

	// Interface used for mocking
	class BitrateAllocatorInterface {
	public:
	virtual void AddObserver(BitrateAllocatorObserver* observer,
	MediaStreamAllocationConfig config) = 0;
	virtual void RemoveObserver(BitrateAllocatorObserver* observer) = 0;
	virtual int GetStartBitrate(BitrateAllocatorObserver* observer) const = 0;

	protected:
	virtual ~BitrateAllocatorInterface() = default;
	};

	// Usage: this class will register multiple RtcpBitrateObserver's one at each
	// RTCP module. It will aggregate the results and run one bandwidth estimation
	// and push the result to the encoders via BitrateAllocatorObserver(s).
	class BitrateAllocator : public BitrateAllocatorInterface {
	public:
	// Used to get notified when send stream limits such as the minimum send
	// bitrate and max padding bitrate is changed.
	class LimitObserver {
	public:
	virtual void OnAllocationLimitsChanged(BitrateAllocationLimits limits) = 0;

	protected:
	virtual ~LimitObserver() = default;
	};

	explicit BitrateAllocator(LimitObserver* limit_observer);
	~BitrateAllocator() override;

	void UpdateStartRate(uint32_t start_rate_bps);

	// Allocate target_bitrate across the registered BitrateAllocatorObservers.
	void OnNetworkEstimateChanged(TargetTransferRate msg);

	// Set the configuration used by the bandwidth management.
	// \|observer\| updates bitrates if already in use.
	// \|config\| is the configuration to use for allocation.
	// Note that \|observer\|->OnBitrateUpdated() will be called
	// within the scope of this method with the current rtt, fraction_loss and
	// available bitrate and that the bitrate in OnBitrateUpdated will be zero if
	// the \|observer\| is currently not allowed to send data.
	void AddObserver(BitrateAllocatorObserver* observer,
	MediaStreamAllocationConfig config) override;

	// Removes a previously added observer, but will not trigger a new bitrate
	// allocation.
	void RemoveObserver(BitrateAllocatorObserver* observer) override;

	// Returns initial bitrate allocated for \|observer\|. If \|observer\| is not in
	// the list of added observers, a best guess is returned.
	int GetStartBitrate(BitrateAllocatorObserver* observer) const override;

	private:
	struct AllocatableTrack {
	AllocatableTrack(BitrateAllocatorObserver* observer,
	MediaStreamAllocationConfig allocation_config)
	: observer(observer),
	config(allocation_config),
	allocated_bitrate_bps(-1),
	media_ratio(1.0) {}
	BitrateAllocatorObserver* observer;
	MediaStreamAllocationConfig config;
	int64_t allocated_bitrate_bps;
	double media_ratio; // Part of the total bitrate used for media [0.0, 1.0].

	uint32_t LastAllocatedBitrate() const;
	// The minimum bitrate required by this observer, including
	// enable-hysteresis if the observer is in a paused state.
	uint32_t MinBitrateWithHysteresis() const;
	};

	// Calculates the minimum requested send bitrate and max padding bitrate and
	// calls LimitObserver::OnAllocationLimitsChanged.
	void UpdateAllocationLimits() RTC_RUN_ON(&sequenced_checker_);

	typedef std::multimap<uint32_t, const AllocatableTrack*> ObserverSortingMap;
	typedef std::map<BitrateAllocatorObserver*, int> ObserverAllocation;

	ObserverAllocation AllocateBitrates(uint32_t bitrate) const
	RTC_RUN_ON(&sequenced_checker_);

	// Allocates zero bitrate to all observers.
	ObserverAllocation ZeroRateAllocation() const RTC_RUN_ON(&sequenced_checker_);
	// Allocates bitrate to observers when there isn't enough to allocate the
	// minimum to all observers.
	ObserverAllocation LowRateAllocation(uint32_t bitrate) const
	RTC_RUN_ON(&sequenced_checker_);
	// Allocates bitrate to all observers when the available bandwidth is enough
	// to allocate the minimum to all observers but not enough to allocate the
	// max bitrate of each observer.
	ObserverAllocation NormalRateAllocation(uint32_t bitrate,
	uint32_t sum_min_bitrates) const
	RTC_RUN_ON(&sequenced_checker_);
	// Allocates bitrate to observers when there is enough available bandwidth
	// for all observers to be allocated their max bitrate.
	ObserverAllocation MaxRateAllocation(uint32_t bitrate,
	uint32_t sum_max_bitrates) const
	RTC_RUN_ON(&sequenced_checker_);

	// Splits \|bitrate\| evenly to observers already in \|allocation\|.
	// \|include_zero_allocations\| decides if zero allocations should be part of
	// the distribution or not. The allowed max bitrate is \|max_multiplier\| x
	// observer max bitrate.
	void DistributeBitrateEvenly(uint32_t bitrate,
	bool include_zero_allocations,
	int max_multiplier,
	ObserverAllocation* allocation) const
	RTC_RUN_ON(&sequenced_checker_);
	bool EnoughBitrateForAllObservers(uint32_t bitrate,
	uint32_t sum_min_bitrates) const
	RTC_RUN_ON(&sequenced_checker_);

	// From the available \|bitrate\|, each observer will be allocated a
	// proportional amount based upon its bitrate priority. If that amount is
	// more than the observer's capacity, it will be allocated its capacity, and
	// the excess bitrate is still allocated proportionally to other observers.
	// Allocating the proportional amount means an observer with twice the
	// bitrate_priority of another will be allocated twice the bitrate.
	void DistributeBitrateRelatively(
	uint32_t bitrate,
	const ObserverAllocation& observers_capacities,
	ObserverAllocation* allocation) const RTC_RUN_ON(&sequenced_checker_);

	// Allow packets to be transmitted in up to 2 times max video bitrate if the
	// bandwidth estimate allows it.
	// TODO(bugs.webrtc.org/8541): May be worth to refactor to keep this logic in
	// video send stream.
	static uint8_t GetTransmissionMaxBitrateMultiplier();

	SequenceChecker sequenced_checker_;
	LimitObserver* const limit_observer_ RTC_GUARDED_BY(&sequenced_checker_);
	// Stored in a list to keep track of the insertion order.
	std::vector<AllocatableTrack> allocatable_tracks_
	RTC_GUARDED_BY(&sequenced_checker_);
	uint32_t last_target_bps_ RTC_GUARDED_BY(&sequenced_checker_);
	uint32_t last_stable_target_bps_ RTC_GUARDED_BY(&sequenced_checker_);
	uint32_t last_non_zero_bitrate_bps_ RTC_GUARDED_BY(&sequenced_checker_);
	uint8_t last_fraction_loss_ RTC_GUARDED_BY(&sequenced_checker_);
	int64_t last_rtt_ RTC_GUARDED_BY(&sequenced_checker_);
	int64_t last_bwe_period_ms_ RTC_GUARDED_BY(&sequenced_checker_);
	// Number of mute events based on too low BWE, not network up/down.
	int num_pause_events_ RTC_GUARDED_BY(&sequenced_checker_);
	int64_t last_bwe_log_time_ RTC_GUARDED_BY(&sequenced_checker_);
	BitrateAllocationLimits current_limits_ RTC_GUARDED_BY(&sequenced_checker_);
	const uint8_t transmission_max_bitrate_multiplier_;
	};

	} // namespace webrtc
	#endif // CALL_BITRATE_ALLOCATOR_H_