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/*
* Copyright (c) 2012 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.
*/
#include "webrtc/modules/remote_bitrate_estimator/overuse_detector.h"
#include <math.h>
#include <stdlib.h>
#include <algorithm>
#include <sstream>
#include <string>
#include "webrtc/base/checks.h"
#include "webrtc/base/common.h"
#include "webrtc/modules/remote_bitrate_estimator/include/bwe_defines.h"
#include "webrtc/modules/remote_bitrate_estimator/test/bwe_test_logging.h"
#include "webrtc/modules/rtp_rtcp/source/rtp_utility.h"
#include "webrtc/system_wrappers/include/field_trial.h"
#include "webrtc/system_wrappers/include/trace.h"
namespace webrtc {
const char kAdaptiveThresholdExperiment[] = "WebRTC-AdaptiveBweThreshold";
const char kEnabledPrefix[] = "Enabled";
const size_t kEnabledPrefixLength = sizeof(kEnabledPrefix) - 1;
const size_t kMinExperimentLength = kEnabledPrefixLength + 3;
const double kMaxAdaptOffsetMs = 15.0;
const double kOverUsingTimeThreshold = 10;
bool AdaptiveThresholdExperimentIsEnabled() {
std::string experiment_string =
webrtc::field_trial::FindFullName(kAdaptiveThresholdExperiment);
if (experiment_string.length() < kMinExperimentLength)
return false;
return experiment_string.substr(0, kEnabledPrefixLength) == kEnabledPrefix;
}
// Gets thresholds from the experiment name following the format
// "WebRTC-AdaptiveBweThreshold/Enabled-0.5,0.002/".
bool ReadExperimentConstants(double* k_up, double* k_down) {
std::string experiment_string =
webrtc::field_trial::FindFullName(kAdaptiveThresholdExperiment);
return sscanf(experiment_string.substr(kEnabledPrefixLength + 1).c_str(),
"%lf,%lf", k_up, k_down) == 2;
}
OveruseDetector::OveruseDetector(const OverUseDetectorOptions& options)
: in_experiment_(AdaptiveThresholdExperimentIsEnabled()),
k_up_(0.01),
k_down_(0.00018),
overusing_time_threshold_(100),
options_(options),
threshold_(12.5),
last_update_ms_(-1),
prev_offset_(0.0),
time_over_using_(-1),
overuse_counter_(0),
hypothesis_(kBwNormal) {
if (in_experiment_)
InitializeExperiment();
}
OveruseDetector::~OveruseDetector() {}
BandwidthUsage OveruseDetector::State() const {
return hypothesis_;
}
BandwidthUsage OveruseDetector::Detect(double offset,
double ts_delta,
int num_of_deltas,
int64_t now_ms) {
if (num_of_deltas < 2) {
return kBwNormal;
}
const double prev_offset = prev_offset_;
prev_offset_ = offset;
const double T = std::min(num_of_deltas, 60) * offset;
BWE_TEST_LOGGING_PLOT(1, "offset", now_ms, T);
BWE_TEST_LOGGING_PLOT(1, "threshold", now_ms, threshold_);
if (T > threshold_) {
if (time_over_using_ == -1) {
// Initialize the timer. Assume that we've been
// over-using half of the time since the previous
// sample.
time_over_using_ = ts_delta / 2;
} else {
// Increment timer
time_over_using_ += ts_delta;
}
overuse_counter_++;
if (time_over_using_ > overusing_time_threshold_ && overuse_counter_ > 1) {
if (offset >= prev_offset) {
time_over_using_ = 0;
overuse_counter_ = 0;
hypothesis_ = kBwOverusing;
}
}
} else if (T < -threshold_) {
time_over_using_ = -1;
overuse_counter_ = 0;
hypothesis_ = kBwUnderusing;
} else {
time_over_using_ = -1;
overuse_counter_ = 0;
hypothesis_ = kBwNormal;
}
UpdateThreshold(T, now_ms);
return hypothesis_;
}
void OveruseDetector::UpdateThreshold(double modified_offset, int64_t now_ms) {
if (!in_experiment_)
return;
if (last_update_ms_ == -1)
last_update_ms_ = now_ms;
if (fabs(modified_offset) > threshold_ + kMaxAdaptOffsetMs) {
// Avoid adapting the threshold to big latency spikes, caused e.g.,
// by a sudden capacity drop.
last_update_ms_ = now_ms;
return;
}
const double k = fabs(modified_offset) < threshold_ ? k_down_ : k_up_;
threshold_ +=
k * (fabs(modified_offset) - threshold_) * (now_ms - last_update_ms_);
const double kMinThreshold = 6;
const double kMaxThreshold = 600;
threshold_ = std::min(std::max(threshold_, kMinThreshold), kMaxThreshold);
last_update_ms_ = now_ms;
}
void OveruseDetector::InitializeExperiment() {
RTC_DCHECK(in_experiment_);
double k_up = 0.0;
double k_down = 0.0;
overusing_time_threshold_ = kOverUsingTimeThreshold;
if (ReadExperimentConstants(&k_up, &k_down)) {
k_up_ = k_up;
k_down_ = k_down;
}
}
} // namespace webrtc
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