147be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org/* 247be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org * Copyright 2011 The WebRTC Project Authors. All rights reserved. 347be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org * 447be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org * Use of this source code is governed by a BSD-style license 547be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org * that can be found in the LICENSE file in the root of the source 647be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org * tree. An additional intellectual property rights grant can be found 747be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org * in the file PATENTS. All contributing project authors may 847be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org * be found in the AUTHORS file in the root of the source tree. 947be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org */ 1047be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org 1147be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org#include "webrtc/base/bandwidthsmoother.h" 1247be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org 1347be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org#include <limits.h> 1447be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org 1547be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.orgnamespace rtc { 1647be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org 1747be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.orgBandwidthSmoother::BandwidthSmoother(int initial_bandwidth_guess, 1847be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org uint32 time_between_increase, 1947be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org double percent_increase, 2047be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org size_t samples_count_to_average, 2147be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org double min_sample_count_percent) 2247be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org : time_between_increase_(time_between_increase), 2347be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org percent_increase_(rtc::_max(1.0, percent_increase)), 2447be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org time_at_last_change_(0), 2547be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org bandwidth_estimation_(initial_bandwidth_guess), 2647be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org accumulator_(samples_count_to_average), 2747be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org min_sample_count_percent_( 2847be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org rtc::_min(1.0, 2947be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org rtc::_max(0.0, min_sample_count_percent))) { 3047be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org} 3147be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org 3247be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org// Samples a new bandwidth measurement 3347be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org// returns true if the bandwidth estimation changed 3447be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.orgbool BandwidthSmoother::Sample(uint32 sample_time, int bandwidth) { 3547be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org if (bandwidth < 0) { 3647be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org return false; 3747be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org } 3847be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org 3947be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org accumulator_.AddSample(bandwidth); 4047be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org 4147be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org if (accumulator_.count() < static_cast<size_t>( 4247be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org accumulator_.max_count() * min_sample_count_percent_)) { 4347be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org // We have not collected enough samples yet. 4447be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org return false; 4547be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org } 4647be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org 4747be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org // Replace bandwidth with the mean of sampled bandwidths. 4847be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org const int mean_bandwidth = static_cast<int>(accumulator_.ComputeMean()); 4947be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org 5047be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org if (mean_bandwidth < bandwidth_estimation_) { 5147be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org time_at_last_change_ = sample_time; 5247be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org bandwidth_estimation_ = mean_bandwidth; 5347be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org return true; 5447be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org } 5547be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org 5647be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org const int old_bandwidth_estimation = bandwidth_estimation_; 5747be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org const double increase_threshold_d = percent_increase_ * bandwidth_estimation_; 5847be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org if (increase_threshold_d > INT_MAX) { 5947be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org // If bandwidth goes any higher we would overflow. 6047be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org return false; 6147be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org } 6247be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org 6347be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org const int increase_threshold = static_cast<int>(increase_threshold_d); 6447be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org if (mean_bandwidth < increase_threshold) { 6547be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org time_at_last_change_ = sample_time; 6647be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org // The value of bandwidth_estimation remains the same if we don't exceed 6747be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org // percent_increase_ * bandwidth_estimation_ for at least 6847be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org // time_between_increase_ time. 6947be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org } else if (sample_time >= time_at_last_change_ + time_between_increase_) { 7047be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org time_at_last_change_ = sample_time; 7147be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org if (increase_threshold == 0) { 7247be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org // Bandwidth_estimation_ must be zero. Assume a jump from zero to a 7347be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org // positive bandwidth means we have regained connectivity. 7447be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org bandwidth_estimation_ = mean_bandwidth; 7547be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org } else { 7647be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org bandwidth_estimation_ = increase_threshold; 7747be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org } 7847be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org } 7947be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org // Else don't make a change. 8047be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org 8147be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org return old_bandwidth_estimation != bandwidth_estimation_; 8247be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org} 8347be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org 8447be73b8629244d6bb63a28198f97f040ce53d21henrike@webrtc.org} // namespace rtc 85