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/*
* Copyright (c) 2016 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/tmmbn.h"
#include <cstddef>
#include <cstdint>
#include "modules/rtp_rtcp/source/rtcp_packet/common_header.h"
#include "modules/rtp_rtcp/source/rtcp_packet/rtpfb.h"
#include "modules/rtp_rtcp/source/rtcp_packet/tmmb_item.h"
#include "rtc_base/checks.h"
#include "rtc_base/logging.h"
namespace webrtc {
namespace rtcp {
// RFC 4585: Feedback format.
// Common packet format:
//
// 0 1 2 3
// 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// |V=2|P| FMT | PT | length |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | SSRC of packet sender |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | SSRC of media source (unused) = 0 |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// : Feedback Control Information (FCI) :
// : :
// Temporary Maximum Media Stream Bit Rate Notification (TMMBN) (RFC 5104).
// The Feedback Control Information (FCI) consists of zero, one, or more
// TMMBN FCI entries.
// 0 1 2 3
// 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | SSRC |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | MxTBR Exp | MxTBR Mantissa |Measured Overhead|
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Tmmbn::Tmmbn() = default;
Tmmbn::~Tmmbn() = default;
bool Tmmbn::Parse(const CommonHeader& packet) {
RTC_DCHECK_EQ(packet.type(), kPacketType);
RTC_DCHECK_EQ(packet.fmt(), kFeedbackMessageType);
if (packet.payload_size_bytes() < kCommonFeedbackLength) {
RTC_LOG(LS_WARNING) << "Payload length " << packet.payload_size_bytes()
<< " is too small for TMMBN.";
return false;
}
size_t items_size_bytes = packet.payload_size_bytes() - kCommonFeedbackLength;
if (items_size_bytes % TmmbItem::kLength != 0) {
RTC_LOG(LS_WARNING) << "Payload length " << packet.payload_size_bytes()
<< " is not valid for TMMBN.";
return false;
}
ParseCommonFeedback(packet.payload());
const uint8_t* next_item = packet.payload() + kCommonFeedbackLength;
size_t number_of_items = items_size_bytes / TmmbItem::kLength;
items_.resize(number_of_items);
for (TmmbItem& item : items_) {
if (!item.Parse(next_item))
return false;
next_item += TmmbItem::kLength;
}
return true;
}
void Tmmbn::AddTmmbr(const TmmbItem& item) {
items_.push_back(item);
}
size_t Tmmbn::BlockLength() const {
return kHeaderLength + kCommonFeedbackLength +
TmmbItem::kLength * items_.size();
}
bool Tmmbn::Create(uint8_t* packet,
size_t* index,
size_t max_length,
PacketReadyCallback callback) const {
while (*index + BlockLength() > max_length) {
if (!OnBufferFull(packet, index, callback))
return false;
}
const size_t index_end = *index + BlockLength();
CreateHeader(kFeedbackMessageType, kPacketType, HeaderLength(), packet,
index);
RTC_DCHECK_EQ(0, Rtpfb::media_ssrc());
CreateCommonFeedback(packet + *index);
*index += kCommonFeedbackLength;
for (const TmmbItem& item : items_) {
item.Create(packet + *index);
*index += TmmbItem::kLength;
}
RTC_CHECK_EQ(index_end, *index);
return true;
}
} // namespace rtcp
} // namespace webrtc
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