| /* |
| * Copyright (c) 2013 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 "modules/remote_bitrate_estimator/inter_arrival.h" |
| |
| #include "modules/include/module_common_types_public.h" |
| #include "rtc_base/logging.h" |
| |
| namespace webrtc { |
| |
| static const int kBurstDeltaThresholdMs = 5; |
| static const int kMaxBurstDurationMs = 100; |
| |
| InterArrival::InterArrival(uint32_t timestamp_group_length_ticks, |
| double timestamp_to_ms_coeff, |
| bool enable_burst_grouping) |
| : kTimestampGroupLengthTicks(timestamp_group_length_ticks), |
| current_timestamp_group_(), |
| prev_timestamp_group_(), |
| timestamp_to_ms_coeff_(timestamp_to_ms_coeff), |
| burst_grouping_(enable_burst_grouping), |
| num_consecutive_reordered_packets_(0) {} |
| |
| bool InterArrival::ComputeDeltas(uint32_t timestamp, |
| int64_t arrival_time_ms, |
| int64_t system_time_ms, |
| size_t packet_size, |
| uint32_t* timestamp_delta, |
| int64_t* arrival_time_delta_ms, |
| int* packet_size_delta) { |
| RTC_DCHECK(timestamp_delta); |
| RTC_DCHECK(arrival_time_delta_ms); |
| RTC_DCHECK(packet_size_delta); |
| bool calculated_deltas = false; |
| if (current_timestamp_group_.IsFirstPacket()) { |
| // We don't have enough data to update the filter, so we store it until we |
| // have two frames of data to process. |
| current_timestamp_group_.timestamp = timestamp; |
| current_timestamp_group_.first_timestamp = timestamp; |
| current_timestamp_group_.first_arrival_ms = arrival_time_ms; |
| } else if (!PacketInOrder(timestamp)) { |
| return false; |
| } else if (NewTimestampGroup(arrival_time_ms, timestamp)) { |
| // First packet of a later frame, the previous frame sample is ready. |
| if (prev_timestamp_group_.complete_time_ms >= 0) { |
| *timestamp_delta = |
| current_timestamp_group_.timestamp - prev_timestamp_group_.timestamp; |
| *arrival_time_delta_ms = current_timestamp_group_.complete_time_ms - |
| prev_timestamp_group_.complete_time_ms; |
| // Check system time differences to see if we have an unproportional jump |
| // in arrival time. In that case reset the inter-arrival computations. |
| int64_t system_time_delta_ms = |
| current_timestamp_group_.last_system_time_ms - |
| prev_timestamp_group_.last_system_time_ms; |
| if (*arrival_time_delta_ms - system_time_delta_ms >= |
| kArrivalTimeOffsetThresholdMs) { |
| RTC_LOG(LS_WARNING) |
| << "The arrival time clock offset has changed (diff = " |
| << *arrival_time_delta_ms - system_time_delta_ms |
| << " ms), resetting."; |
| Reset(); |
| return false; |
| } |
| if (*arrival_time_delta_ms < 0) { |
| // The group of packets has been reordered since receiving its local |
| // arrival timestamp. |
| ++num_consecutive_reordered_packets_; |
| if (num_consecutive_reordered_packets_ >= kReorderedResetThreshold) { |
| RTC_LOG(LS_WARNING) |
| << "Packets are being reordered on the path from the " |
| "socket to the bandwidth estimator. Ignoring this " |
| "packet for bandwidth estimation, resetting."; |
| Reset(); |
| } |
| return false; |
| } else { |
| num_consecutive_reordered_packets_ = 0; |
| } |
| RTC_DCHECK_GE(*arrival_time_delta_ms, 0); |
| *packet_size_delta = static_cast<int>(current_timestamp_group_.size) - |
| static_cast<int>(prev_timestamp_group_.size); |
| calculated_deltas = true; |
| } |
| prev_timestamp_group_ = current_timestamp_group_; |
| // The new timestamp is now the current frame. |
| current_timestamp_group_.first_timestamp = timestamp; |
| current_timestamp_group_.timestamp = timestamp; |
| current_timestamp_group_.first_arrival_ms = arrival_time_ms; |
| current_timestamp_group_.size = 0; |
| } else { |
| current_timestamp_group_.timestamp = |
| LatestTimestamp(current_timestamp_group_.timestamp, timestamp); |
| } |
| // Accumulate the frame size. |
| current_timestamp_group_.size += packet_size; |
| current_timestamp_group_.complete_time_ms = arrival_time_ms; |
| current_timestamp_group_.last_system_time_ms = system_time_ms; |
| |
| return calculated_deltas; |
| } |
| |
| bool InterArrival::PacketInOrder(uint32_t timestamp) { |
| if (current_timestamp_group_.IsFirstPacket()) { |
| return true; |
| } else { |
| // Assume that a diff which is bigger than half the timestamp interval |
| // (32 bits) must be due to reordering. This code is almost identical to |
| // that in IsNewerTimestamp() in module_common_types.h. |
| uint32_t timestamp_diff = |
| timestamp - current_timestamp_group_.first_timestamp; |
| return timestamp_diff < 0x80000000; |
| } |
| } |
| |
| // Assumes that |timestamp| is not reordered compared to |
| // |current_timestamp_group_|. |
| bool InterArrival::NewTimestampGroup(int64_t arrival_time_ms, |
| uint32_t timestamp) const { |
| if (current_timestamp_group_.IsFirstPacket()) { |
| return false; |
| } else if (BelongsToBurst(arrival_time_ms, timestamp)) { |
| return false; |
| } else { |
| uint32_t timestamp_diff = |
| timestamp - current_timestamp_group_.first_timestamp; |
| return timestamp_diff > kTimestampGroupLengthTicks; |
| } |
| } |
| |
| bool InterArrival::BelongsToBurst(int64_t arrival_time_ms, |
| uint32_t timestamp) const { |
| if (!burst_grouping_) { |
| return false; |
| } |
| RTC_DCHECK_GE(current_timestamp_group_.complete_time_ms, 0); |
| int64_t arrival_time_delta_ms = |
| arrival_time_ms - current_timestamp_group_.complete_time_ms; |
| uint32_t timestamp_diff = timestamp - current_timestamp_group_.timestamp; |
| int64_t ts_delta_ms = timestamp_to_ms_coeff_ * timestamp_diff + 0.5; |
| if (ts_delta_ms == 0) |
| return true; |
| int propagation_delta_ms = arrival_time_delta_ms - ts_delta_ms; |
| if (propagation_delta_ms < 0 && |
| arrival_time_delta_ms <= kBurstDeltaThresholdMs && |
| arrival_time_ms - current_timestamp_group_.first_arrival_ms < |
| kMaxBurstDurationMs) |
| return true; |
| return false; |
| } |
| |
| void InterArrival::Reset() { |
| num_consecutive_reordered_packets_ = 0; |
| current_timestamp_group_ = TimestampGroup(); |
| prev_timestamp_group_ = TimestampGroup(); |
| } |
| } // namespace webrtc |
