chromium/third_party/webrtc/modules/audio_coding/neteq/nack_tracker.h

/*
 *  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.
 */

#ifndef MODULES_AUDIO_CODING_NETEQ_NACK_TRACKER_H_
#define MODULES_AUDIO_CODING_NETEQ_NACK_TRACKER_H_

#include <stddef.h>
#include <stdint.h>

#include <map>
#include <vector>

#include "absl/types/optional.h"
#include "api/field_trials_view.h"
#include "modules/include/module_common_types_public.h"
#include "rtc_base/gtest_prod_util.h"

//
// The NackTracker class keeps track of the lost packets, an estimate of
// time-to-play for each packet is also given.
//
// Every time a packet is pushed into NetEq, LastReceivedPacket() has to be
// called to update the NACK list.
//
// Every time 10ms audio is pulled from NetEq LastDecodedPacket() should be
// called, and time-to-play is updated at that moment.
//
// If packet N is received, any packet prior to N which has not arrived is
// considered lost, and should be labeled as "missing" (the size of
// the list might be limited and older packet eliminated from the list).
//
// The NackTracker class has to know about the sample rate of the packets to
// compute time-to-play. So sample rate should be set as soon as the first
// packet is received. If there is a change in the receive codec (sender changes
// codec) then NackTracker should be reset. This is because NetEQ would flush
// its buffer and re-transmission is meaning less for old packet. Therefore, in
// that case, after reset the sampling rate has to be updated.
//
// Thread Safety
// =============
// Please note that this class in not thread safe. The class must be protected
// if different APIs are called from different threads.
//
namespace webrtc {

class NackTracker { … };

}  // namespace webrtc

#endif  // MODULES_AUDIO_CODING_NETEQ_NACK_TRACKER_H_