blob: 2603a6715e6ac2b2e23b4b02f9d1421b09ad15d0 [file] [log] [blame]
* Copyright (c) 2019 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/rtp_rtcp/source/rtcp_packet/common_header.h"
#include "modules/rtp_rtcp/source/rtcp_packet/psfb.h"
#include "rtc_base/system/unused.h"
namespace webrtc {
namespace rtcp {
class LossNotification : public Psfb {
LossNotification(uint16_t last_decoded,
uint16_t last_received,
bool decodability_flag);
LossNotification(const LossNotification& other);
~LossNotification() override;
size_t BlockLength() const override;
bool Create(uint8_t* packet,
size_t* index,
size_t max_length,
PacketReadyCallback callback) const override
// Parse assumes header is already parsed and validated.
bool Parse(const CommonHeader& packet) RTC_WARN_UNUSED_RESULT;
// Set all of the values transmitted by the loss notification message.
// If the values may not be represented by a loss notification message,
// false is returned, and no change is made to the object; this happens
// when |last_recieved| is ahead of |last_decoded| by more than 0x7fff.
// This is because |last_recieved| is represented on the wire as a delta,
// and only 15 bits are available for that delta.
bool Set(uint16_t last_decoded,
uint16_t last_received,
bool decodability_flag) RTC_WARN_UNUSED_RESULT;
// RTP sequence number of the first packet belong to the last decoded
// non-discardable frame.
uint16_t last_decoded() const { return last_decoded_; }
// RTP sequence number of the last received packet.
uint16_t last_received() const { return last_received_; }
// A decodability flag, whose specific meaning depends on the last-received
// RTP sequence number. The decodability flag is true if and only if all of
// the frame's dependencies are known to be decodable, and the frame itself
// is not yet known to be unassemblable.
// * Clarification #1: In a multi-packet frame, the first packet's
// dependencies are known, but it is not yet known whether all parts
// of the current frame will be received.
// * Clarification #2: In a multi-packet frame, the dependencies would be
// unknown if the first packet was not received. Then, the packet will
// be known-unassemblable.
bool decodability_flag() const { return decodability_flag_; }
static constexpr uint32_t kUniqueIdentifier = 0x4C4E5446; // 'L' 'N' 'T' 'F'.
static constexpr size_t kLossNotificationPayloadLength = 8;
uint16_t last_decoded_;
uint16_t last_received_;
bool decodability_flag_;
} // namespace rtcp
} // namespace webrtc