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| 1 /* |
| 2 * Copyright (c) 2016 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 |
| 11 #include "webrtc/modules/congestion_controller/probe_controller.h" |
| 12 |
| 13 #include <initializer_list> |
| 14 |
| 15 #include "webrtc/base/logging.h" |
| 16 |
| 17 namespace webrtc { |
| 18 |
| 19 namespace { |
| 20 |
| 21 // Number of deltas between probes per cluster. On the very first cluster, |
| 22 // we will need kProbeDeltasPerCluster + 1 probes, but on a cluster following |
| 23 // another, we need kProbeDeltasPerCluster probes. |
| 24 constexpr int kProbeDeltasPerCluster = 5; |
| 25 |
| 26 // Maximum waiting time from the time of initiating probing to getting |
| 27 // the measured results back. |
| 28 constexpr int64_t kMaxWaitingTimeForProbingResultMs = 1000; |
| 29 |
| 30 // Value of |min_bitrate_to_probe_further_bps_| that indicates |
| 31 // further probing is disabled. |
| 32 constexpr int kExponentialProbingDisabled = 0; |
| 33 |
| 34 } // namespace |
| 35 |
| 36 ProbeController::ProbeController(PacedSender* pacer, Clock* clock) |
| 37 : pacer_(pacer), |
| 38 clock_(clock), |
| 39 state_(State::kInit), |
| 40 min_bitrate_to_probe_further_bps_(kExponentialProbingDisabled), |
| 41 time_last_probing_initiated_ms_(0), |
| 42 estimated_bitrate_bps_(0), |
| 43 max_bitrate_bps_(0) {} |
| 44 |
| 45 void ProbeController::SetBitrates(int min_bitrate_bps, |
| 46 int start_bitrate_bps, |
| 47 int max_bitrate_bps) { |
| 48 rtc::CritScope cs(&critsect_); |
| 49 if (state_ == State::kInit) { |
| 50 // When probing at 1.8 Mbps ( 6x 300), this represents a threshold of |
| 51 // 1.2 Mbps to continue probing. |
| 52 InitiateProbing({3 * start_bitrate_bps, 6 * start_bitrate_bps}, |
| 53 4 * start_bitrate_bps); |
| 54 } |
| 55 |
| 56 // Only do probing if: |
| 57 // - we are mid-call, which we consider to be if |
| 58 // |estimated_bitrate_bps_| != 0, and |
| 59 // - the current bitrate is lower than the new |max_bitrate_bps|, and |
| 60 // - we actually want to increase the |max_bitrate_bps_|. |
| 61 if (estimated_bitrate_bps_ != 0 && estimated_bitrate_bps_ < max_bitrate_bps && |
| 62 max_bitrate_bps > max_bitrate_bps_) { |
| 63 InitiateProbing({max_bitrate_bps}, kExponentialProbingDisabled); |
| 64 } |
| 65 max_bitrate_bps_ = max_bitrate_bps; |
| 66 } |
| 67 |
| 68 void ProbeController::SetEstimatedBitrate(int bitrate_bps) { |
| 69 rtc::CritScope cs(&critsect_); |
| 70 if (state_ == State::kWaitingForProbingResult) { |
| 71 if ((clock_->TimeInMilliseconds() - time_last_probing_initiated_ms_) > |
| 72 kMaxWaitingTimeForProbingResultMs) { |
| 73 LOG(LS_INFO) << "kWaitingForProbingResult: timeout"; |
| 74 state_ = State::kProbingComplete; |
| 75 min_bitrate_to_probe_further_bps_ = kExponentialProbingDisabled; |
| 76 } else { |
| 77 // Continue probing if probing results indicate channel has greater |
| 78 // capacity. |
| 79 LOG(LS_INFO) << "Measured bitrate: " << bitrate_bps |
| 80 << " Minimum to probe further: " |
| 81 << min_bitrate_to_probe_further_bps_; |
| 82 if (min_bitrate_to_probe_further_bps_ != kExponentialProbingDisabled && |
| 83 bitrate_bps > min_bitrate_to_probe_further_bps_) { |
| 84 // Double the probing bitrate and expect a minimum of 25% gain to |
| 85 // continue probing. |
| 86 InitiateProbing({2 * bitrate_bps}, 1.25 * bitrate_bps); |
| 87 } |
| 88 } |
| 89 } |
| 90 estimated_bitrate_bps_ = bitrate_bps; |
| 91 } |
| 92 |
| 93 void ProbeController::InitiateProbing( |
| 94 std::initializer_list<int> bitrates_to_probe, |
| 95 int min_bitrate_to_probe_further_bps) { |
| 96 bool first_cluster = true; |
| 97 for (int bitrate : bitrates_to_probe) { |
| 98 if (first_cluster) { |
| 99 pacer_->CreateProbeCluster(bitrate, kProbeDeltasPerCluster + 1); |
| 100 first_cluster = false; |
| 101 } else { |
| 102 pacer_->CreateProbeCluster(bitrate, kProbeDeltasPerCluster); |
| 103 } |
| 104 } |
| 105 min_bitrate_to_probe_further_bps_ = min_bitrate_to_probe_further_bps; |
| 106 time_last_probing_initiated_ms_ = clock_->TimeInMilliseconds(); |
| 107 if (min_bitrate_to_probe_further_bps == kExponentialProbingDisabled) |
| 108 state_ = State::kProbingComplete; |
| 109 else |
| 110 state_ = State::kWaitingForProbingResult; |
| 111 } |
| 112 |
| 113 } // namespace webrtc |
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