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| 1 /* | |
| 2 * Copyright 2011 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/base/bandwidthsmoother.h" | |
| 12 | |
| 13 #include <limits.h> | |
| 14 #include <algorithm> | |
| 15 | |
| 16 namespace rtc { | |
| 17 | |
| 18 BandwidthSmoother::BandwidthSmoother(int initial_bandwidth_guess, | |
| 19 uint32_t time_between_increase, | |
| 20 double percent_increase, | |
| 21 size_t samples_count_to_average, | |
| 22 double min_sample_count_percent) | |
| 23 : time_between_increase_(time_between_increase), | |
| 24 percent_increase_(std::max(1.0, percent_increase)), | |
| 25 time_at_last_change_(0), | |
| 26 bandwidth_estimation_(initial_bandwidth_guess), | |
| 27 accumulator_(samples_count_to_average), | |
| 28 min_sample_count_percent_( | |
| 29 std::min(1.0, std::max(0.0, min_sample_count_percent))) { | |
| 30 } | |
| 31 | |
| 32 BandwidthSmoother::~BandwidthSmoother() = default; | |
| 33 | |
| 34 // Samples a new bandwidth measurement | |
| 35 // returns true if the bandwidth estimation changed | |
| 36 bool BandwidthSmoother::Sample(uint32_t sample_time, int bandwidth) { | |
| 37 if (bandwidth < 0) { | |
| 38 return false; | |
| 39 } | |
| 40 | |
| 41 accumulator_.AddSample(bandwidth); | |
| 42 | |
| 43 if (accumulator_.count() < static_cast<size_t>( | |
| 44 accumulator_.max_count() * min_sample_count_percent_)) { | |
| 45 // We have not collected enough samples yet. | |
| 46 return false; | |
| 47 } | |
| 48 | |
| 49 // Replace bandwidth with the mean of sampled bandwidths. | |
| 50 const int mean_bandwidth = static_cast<int>(accumulator_.ComputeMean()); | |
| 51 | |
| 52 if (mean_bandwidth < bandwidth_estimation_) { | |
| 53 time_at_last_change_ = sample_time; | |
| 54 bandwidth_estimation_ = mean_bandwidth; | |
| 55 return true; | |
| 56 } | |
| 57 | |
| 58 const int old_bandwidth_estimation = bandwidth_estimation_; | |
| 59 const double increase_threshold_d = percent_increase_ * bandwidth_estimation_; | |
| 60 if (increase_threshold_d > INT_MAX) { | |
| 61 // If bandwidth goes any higher we would overflow. | |
| 62 return false; | |
| 63 } | |
| 64 | |
| 65 const int increase_threshold = static_cast<int>(increase_threshold_d); | |
| 66 if (mean_bandwidth < increase_threshold) { | |
| 67 time_at_last_change_ = sample_time; | |
| 68 // The value of bandwidth_estimation remains the same if we don't exceed | |
| 69 // percent_increase_ * bandwidth_estimation_ for at least | |
| 70 // time_between_increase_ time. | |
| 71 } else if (sample_time >= time_at_last_change_ + time_between_increase_) { | |
| 72 time_at_last_change_ = sample_time; | |
| 73 if (increase_threshold == 0) { | |
| 74 // Bandwidth_estimation_ must be zero. Assume a jump from zero to a | |
| 75 // positive bandwidth means we have regained connectivity. | |
| 76 bandwidth_estimation_ = mean_bandwidth; | |
| 77 } else { | |
| 78 bandwidth_estimation_ = increase_threshold; | |
| 79 } | |
| 80 } | |
| 81 // Else don't make a change. | |
| 82 | |
| 83 return old_bandwidth_estimation != bandwidth_estimation_; | |
| 84 } | |
| 85 | |
| 86 } // namespace rtc | |
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Chromium Code Reviews
Issue 2367213004:
Delete bandwidthsmoother.h. (Closed)
