| /* |
| * 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/audio_coding/neteq/delay_peak_detector.h" |
| |
| #include <algorithm> // max |
| |
| #include "webrtc/rtc_base/checks.h" |
| #include "webrtc/rtc_base/safe_conversions.h" |
| |
| namespace webrtc { |
| |
| // The DelayPeakDetector keeps track of severe inter-arrival times, called |
| // delay peaks. When a peak is observed, the "height" (the time elapsed since |
| // the previous packet arrival) and the peak "period" (the time since the last |
| // observed peak) is recorded in a vector. When enough peaks have been observed, |
| // peak-mode is engaged and the DelayManager asks the DelayPeakDetector for |
| // the worst peak height. |
| |
| DelayPeakDetector::~DelayPeakDetector() = default; |
| |
| DelayPeakDetector::DelayPeakDetector(const TickTimer* tick_timer) |
| : peak_found_(false), |
| peak_detection_threshold_(0), |
| tick_timer_(tick_timer) { |
| RTC_DCHECK(!peak_period_stopwatch_); |
| } |
| |
| void DelayPeakDetector::Reset() { |
| peak_period_stopwatch_.reset(); |
| peak_found_ = false; |
| peak_history_.clear(); |
| } |
| |
| // Calculates the threshold in number of packets. |
| void DelayPeakDetector::SetPacketAudioLength(int length_ms) { |
| if (length_ms > 0) { |
| peak_detection_threshold_ = kPeakHeightMs / length_ms; |
| } |
| } |
| |
| bool DelayPeakDetector::peak_found() { |
| return peak_found_; |
| } |
| |
| int DelayPeakDetector::MaxPeakHeight() const { |
| int max_height = -1; // Returns -1 for an empty history. |
| std::list<Peak>::const_iterator it; |
| for (it = peak_history_.begin(); it != peak_history_.end(); ++it) { |
| max_height = std::max(max_height, it->peak_height_packets); |
| } |
| return max_height; |
| } |
| |
| uint64_t DelayPeakDetector::MaxPeakPeriod() const { |
| auto max_period_element = std::max_element( |
| peak_history_.begin(), peak_history_.end(), |
| [](Peak a, Peak b) { return a.period_ms < b.period_ms; }); |
| if (max_period_element == peak_history_.end()) { |
| return 0; // |peak_history_| is empty. |
| } |
| RTC_DCHECK_GT(max_period_element->period_ms, 0); |
| return max_period_element->period_ms; |
| } |
| |
| bool DelayPeakDetector::Update(int inter_arrival_time, int target_level) { |
| if (inter_arrival_time > target_level + peak_detection_threshold_ || |
| inter_arrival_time > 2 * target_level) { |
| // A delay peak is observed. |
| if (!peak_period_stopwatch_) { |
| // This is the first peak. Reset the period counter. |
| peak_period_stopwatch_ = tick_timer_->GetNewStopwatch(); |
| } else if (peak_period_stopwatch_->ElapsedMs() > 0) { |
| if (peak_period_stopwatch_->ElapsedMs() <= kMaxPeakPeriodMs) { |
| // This is not the first peak, and the period is valid. |
| // Store peak data in the vector. |
| Peak peak_data; |
| peak_data.period_ms = peak_period_stopwatch_->ElapsedMs(); |
| peak_data.peak_height_packets = inter_arrival_time; |
| peak_history_.push_back(peak_data); |
| while (peak_history_.size() > kMaxNumPeaks) { |
| // Delete the oldest data point. |
| peak_history_.pop_front(); |
| } |
| peak_period_stopwatch_ = tick_timer_->GetNewStopwatch(); |
| } else if (peak_period_stopwatch_->ElapsedMs() <= 2 * kMaxPeakPeriodMs) { |
| // Invalid peak due to too long period. Reset period counter and start |
| // looking for next peak. |
| peak_period_stopwatch_ = tick_timer_->GetNewStopwatch(); |
| } else { |
| // More than 2 times the maximum period has elapsed since the last peak |
| // was registered. It seams that the network conditions have changed. |
| // Reset the peak statistics. |
| Reset(); |
| } |
| } |
| } |
| return CheckPeakConditions(); |
| } |
| |
| bool DelayPeakDetector::CheckPeakConditions() { |
| size_t s = peak_history_.size(); |
| if (s >= kMinPeaksToTrigger && |
| peak_period_stopwatch_->ElapsedMs() <= 2 * MaxPeakPeriod()) { |
| peak_found_ = true; |
| } else { |
| peak_found_ = false; |
| } |
| return peak_found_; |
| } |
| } // namespace webrtc |