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      1 /*
      2  *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
      3  *
      4  *  Use of this source code is governed by a BSD-style license
      5  *  that can be found in the LICENSE file in the root of the source
      6  *  tree. An additional intellectual property rights grant can be found
      7  *  in the file PATENTS.  All contributing project authors may
      8  *  be found in the AUTHORS file in the root of the source tree.
      9  *
     10  *  Usage: this class will register multiple RtcpBitrateObserver's one at each
     11  *  RTCP module. It will aggregate the results and run one bandwidth estimation
     12  *  and push the result to the encoders via BitrateObserver(s).
     13  */
     14 
     15 #ifndef WEBRTC_MODULES_BITRATE_CONTROLLER_INCLUDE_BITRATE_CONTROLLER_H_
     16 #define WEBRTC_MODULES_BITRATE_CONTROLLER_INCLUDE_BITRATE_CONTROLLER_H_
     17 
     18 #include "webrtc/modules/interface/module.h"
     19 #include "webrtc/modules/rtp_rtcp/interface/rtp_rtcp_defines.h"
     20 
     21 namespace webrtc {
     22 
     23 class BitrateObserver {
     24  /*
     25   * Observer class for the encoders, each encoder should implement this class
     26   * to get the target bitrate. It also get the fraction loss and rtt to
     27   * optimize its settings for this type of network. |target_bitrate| is the
     28   * target media/payload bitrate excluding packet headers, measured in bits
     29   * per second.
     30   */
     31  public:
     32   virtual void OnNetworkChanged(const uint32_t target_bitrate,
     33                                 const uint8_t fraction_loss,  // 0 - 255.
     34                                 const uint32_t rtt) = 0;
     35 
     36   virtual ~BitrateObserver() {}
     37 };
     38 
     39 class BitrateController : public Module {
     40 /*
     41  * This class collects feedback from all streams sent to a peer (via
     42  * RTCPBandwidthObservers). It does one  aggregated send side bandwidth
     43  * estimation and divide the available bitrate between all its registered
     44  * BitrateObservers.
     45  */
     46  public:
     47   // The argument |enforce_min_bitrate| controls the behavior when the available
     48   // bitrate is lower than the minimum bitrate, or the sum of minimum bitrates.
     49   // When true, the bitrate will never be set lower than the minimum bitrate(s).
     50   // When false, the bitrate observers will be allocated rates up to their
     51   // respective minimum bitrate, satisfying one observer after the other.
     52   static BitrateController* CreateBitrateController(Clock* clock,
     53                                                     bool enforce_min_bitrate);
     54   virtual ~BitrateController() {}
     55 
     56   virtual RtcpBandwidthObserver* CreateRtcpBandwidthObserver() = 0;
     57 
     58   // Gets the available payload bandwidth in bits per second. Note that
     59   // this bandwidth excludes packet headers.
     60   virtual bool AvailableBandwidth(uint32_t* bandwidth) const = 0;
     61 
     62   /*
     63   *  Set the start and max send bitrate used by the bandwidth management.
     64   *
     65   *  observer, updates bitrates if already in use.
     66   *  min_bitrate_kbit = 0 equals no min bitrate.
     67   *  max_bitrate_kit = 0 equals no max bitrate.
     68   */
     69   virtual void SetBitrateObserver(BitrateObserver* observer,
     70                                   const uint32_t start_bitrate,
     71                                   const uint32_t min_bitrate,
     72                                   const uint32_t max_bitrate) = 0;
     73 
     74   virtual void RemoveBitrateObserver(BitrateObserver* observer) = 0;
     75 
     76   // Changes the mode that was set in the constructor.
     77   virtual void EnforceMinBitrate(bool enforce_min_bitrate) = 0;
     78 
     79   virtual void SetReservedBitrate(uint32_t reserved_bitrate_bps) = 0;
     80 };
     81 }  // namespace webrtc
     82 #endif  // WEBRTC_MODULES_BITRATE_CONTROLLER_INCLUDE_BITRATE_CONTROLLER_H_
     83