ACM: Move NACK functionality inside NetEq

webrtc/modules/audio_coding/main/acm2/nack.cc

-/*
- *  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 "webrtc/modules/audio_coding/main/acm2/nack.h"
-
-#include <assert.h>  // For assert.
-
-#include <algorithm>  // For std::max.
-
-#include "webrtc/modules/interface/module_common_types.h"
-#include "webrtc/system_wrappers/include/logging.h"
-
-namespace webrtc {
-
-namespace acm2 {
-
-namespace {
-
-const int kDefaultSampleRateKhz = 48;
-const int kDefaultPacketSizeMs = 20;
-
-}  // namespace
-
-Nack::Nack(int nack_threshold_packets)
-    : nack_threshold_packets_(nack_threshold_packets),
-      sequence_num_last_received_rtp_(0),
-      timestamp_last_received_rtp_(0),
-      any_rtp_received_(false),
-      sequence_num_last_decoded_rtp_(0),
-      timestamp_last_decoded_rtp_(0),
-      any_rtp_decoded_(false),
-      sample_rate_khz_(kDefaultSampleRateKhz),
-      samples_per_packet_(sample_rate_khz_ * kDefaultPacketSizeMs),
-      max_nack_list_size_(kNackListSizeLimit) {}
-
-Nack::~Nack() = default;
-
-Nack* Nack::Create(int nack_threshold_packets) {
-  return new Nack(nack_threshold_packets);
-}
-
-void Nack::UpdateSampleRate(int sample_rate_hz) {
-  assert(sample_rate_hz > 0);
-  sample_rate_khz_ = sample_rate_hz / 1000;
-}
-
-void Nack::UpdateLastReceivedPacket(uint16_t sequence_number,
-                                    uint32_t timestamp) {
-  // Just record the value of sequence number and timestamp if this is the
-  // first packet.
-  if (!any_rtp_received_) {
-    sequence_num_last_received_rtp_ = sequence_number;
-    timestamp_last_received_rtp_ = timestamp;
-    any_rtp_received_ = true;
-    // If no packet is decoded, to have a reasonable estimate of time-to-play
-    // use the given values.
-    if (!any_rtp_decoded_) {
-      sequence_num_last_decoded_rtp_ = sequence_number;
-      timestamp_last_decoded_rtp_ = timestamp;
-    }
-    return;
-  }
-
-  if (sequence_number == sequence_num_last_received_rtp_)
-    return;
-
-  // Received RTP should not be in the list.
-  nack_list_.erase(sequence_number);
-
-  // If this is an old sequence number, no more action is required, return.
-  if (IsNewerSequenceNumber(sequence_num_last_received_rtp_, sequence_number))
-    return;
-
-  UpdateSamplesPerPacket(sequence_number, timestamp);
-
-  UpdateList(sequence_number);
-
-  sequence_num_last_received_rtp_ = sequence_number;
-  timestamp_last_received_rtp_ = timestamp;
-  LimitNackListSize();
-}
-
-void Nack::UpdateSamplesPerPacket(uint16_t sequence_number_current_received_rtp,
-                                  uint32_t timestamp_current_received_rtp) {
-  uint32_t timestamp_increase = timestamp_current_received_rtp -
-      timestamp_last_received_rtp_;
-  uint16_t sequence_num_increase = sequence_number_current_received_rtp -
-      sequence_num_last_received_rtp_;
-
-  samples_per_packet_ = timestamp_increase / sequence_num_increase;
-}
-
-void Nack::UpdateList(uint16_t sequence_number_current_received_rtp) {
-  // Some of the packets which were considered late, now are considered missing.
-  ChangeFromLateToMissing(sequence_number_current_received_rtp);
-
-  if (IsNewerSequenceNumber(sequence_number_current_received_rtp,
-                            sequence_num_last_received_rtp_ + 1))
-    AddToList(sequence_number_current_received_rtp);
-}
-
-void Nack::ChangeFromLateToMissing(
-    uint16_t sequence_number_current_received_rtp) {
-  NackList::const_iterator lower_bound = nack_list_.lower_bound(
-      static_cast<uint16_t>(sequence_number_current_received_rtp -
-                            nack_threshold_packets_));
-
-  for (NackList::iterator it = nack_list_.begin(); it != lower_bound; ++it)
-    it->second.is_missing = true;
-}
-
-uint32_t Nack::EstimateTimestamp(uint16_t sequence_num) {
-  uint16_t sequence_num_diff = sequence_num - sequence_num_last_received_rtp_;
-  return sequence_num_diff * samples_per_packet_ + timestamp_last_received_rtp_;
-}
-
-void Nack::AddToList(uint16_t sequence_number_current_received_rtp) {
-  assert(!any_rtp_decoded_ || IsNewerSequenceNumber(
-      sequence_number_current_received_rtp, sequence_num_last_decoded_rtp_));
-
-  // Packets with sequence numbers older than |upper_bound_missing| are
-  // considered missing, and the rest are considered late.
-  uint16_t upper_bound_missing = sequence_number_current_received_rtp -
-      nack_threshold_packets_;
-
-  for (uint16_t n = sequence_num_last_received_rtp_ + 1;
-      IsNewerSequenceNumber(sequence_number_current_received_rtp, n); ++n) {
-    bool is_missing = IsNewerSequenceNumber(upper_bound_missing, n);
-    uint32_t timestamp = EstimateTimestamp(n);
-    NackElement nack_element(TimeToPlay(timestamp), timestamp, is_missing);
-    nack_list_.insert(nack_list_.end(), std::make_pair(n, nack_element));
-  }
-}
-
-void Nack::UpdateEstimatedPlayoutTimeBy10ms() {
-  while (!nack_list_.empty() &&
-      nack_list_.begin()->second.time_to_play_ms <= 10)
-    nack_list_.erase(nack_list_.begin());
-
-  for (NackList::iterator it = nack_list_.begin(); it != nack_list_.end(); ++it)
-    it->second.time_to_play_ms -= 10;
-}
-
-void Nack::UpdateLastDecodedPacket(uint16_t sequence_number,
-                                   uint32_t timestamp) {
-  if (IsNewerSequenceNumber(sequence_number, sequence_num_last_decoded_rtp_) ||
-      !any_rtp_decoded_) {
-    sequence_num_last_decoded_rtp_ = sequence_number;
-    timestamp_last_decoded_rtp_ = timestamp;
-    // Packets in the list with sequence numbers less than the
-    // sequence number of the decoded RTP should be removed from the lists.
-    // They will be discarded by the jitter buffer if they arrive.
-    nack_list_.erase(nack_list_.begin(), nack_list_.upper_bound(
-        sequence_num_last_decoded_rtp_));
-
-    // Update estimated time-to-play.
-    for (NackList::iterator it = nack_list_.begin(); it != nack_list_.end();
-        ++it)
-      it->second.time_to_play_ms = TimeToPlay(it->second.estimated_timestamp);
-  } else {
-    assert(sequence_number == sequence_num_last_decoded_rtp_);
-
-    // Same sequence number as before. 10 ms is elapsed, update estimations for
-    // time-to-play.
-    UpdateEstimatedPlayoutTimeBy10ms();
-
-    // Update timestamp for better estimate of time-to-play, for packets which
-    // are added to NACK list later on.
-    timestamp_last_decoded_rtp_ += sample_rate_khz_ * 10;
-  }
-  any_rtp_decoded_ = true;
-}
-
-Nack::NackList Nack::GetNackList() const {
-  return nack_list_;
-}
-
-void Nack::Reset() {
-  nack_list_.clear();
-
-  sequence_num_last_received_rtp_ = 0;
-  timestamp_last_received_rtp_ = 0;
-  any_rtp_received_ = false;
-  sequence_num_last_decoded_rtp_ = 0;
-  timestamp_last_decoded_rtp_ = 0;
-  any_rtp_decoded_ = false;
-  sample_rate_khz_ = kDefaultSampleRateKhz;
-  samples_per_packet_ = sample_rate_khz_ * kDefaultPacketSizeMs;
-}
-
-int Nack::SetMaxNackListSize(size_t max_nack_list_size) {
-  if (max_nack_list_size == 0 || max_nack_list_size > kNackListSizeLimit)
-    return -1;
-  max_nack_list_size_ = max_nack_list_size;
-  LimitNackListSize();
-  return 0;
-}
-
-void Nack::LimitNackListSize() {
-  uint16_t limit = sequence_num_last_received_rtp_ -
-      static_cast<uint16_t>(max_nack_list_size_) - 1;
-  nack_list_.erase(nack_list_.begin(), nack_list_.upper_bound(limit));
-}
-
-int64_t Nack::TimeToPlay(uint32_t timestamp) const {
-  uint32_t timestamp_increase = timestamp - timestamp_last_decoded_rtp_;
-  return timestamp_increase / sample_rate_khz_;
-}
-
-// We don't erase elements with time-to-play shorter than round-trip-time.
-std::vector<uint16_t> Nack::GetNackList(int64_t round_trip_time_ms) const {
-  std::vector<uint16_t> sequence_numbers;
-  for (NackList::const_iterator it = nack_list_.begin(); it != nack_list_.end();
-      ++it) {
-    if (it->second.is_missing &&
-        it->second.time_to_play_ms > round_trip_time_ms)
-      sequence_numbers.push_back(it->first);
-  }
-  return sequence_numbers;
-}
-
-}  // namespace acm2
-
-}  // namespace webrtc