ZLMediaKit/webrtc/TwccContext.cpp

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2021-10-06 22:17:38 +08:00
/*
* Copyright (c) 2021 The ZLMediaKit project authors. All Rights Reserved.
*
* This file is part of ZLMediaKit(https://github.com/xia-chu/ZLMediaKit).
*
* Use of this source code is governed by MIT license that can be found in the
* LICENSE file in the root of the source tree. All contributing project authors
* may be found in the AUTHORS file in the root of the source tree.
*/
#include "TwccContext.h"
enum class ExtSeqStatus : int {
normal = 0,
looped,
jumped,
};
void TwccContext::onRtp(uint16_t twcc_ext_seq) {
switch ((ExtSeqStatus) checkSeqStatus(twcc_ext_seq)) {
case ExtSeqStatus::jumped: /*回环后收到回环前的大ext seq包,过滤掉*/ return;
case ExtSeqStatus::looped: /*回环触发发送twcc rtcp*/ onSendTwcc(); break;
case ExtSeqStatus::normal: break;
default: /*不可达*/assert(0); break;
}
auto result = _rtp_recv_status.emplace(twcc_ext_seq, _ticker.createdTime());
if (!result.second) {
WarnL << "recv same twcc ext seq:" << twcc_ext_seq;
return;
}
_max_stamp = result.first->second;
if (!_min_stamp) {
_min_stamp = _max_stamp;
}
if (checkIfNeedSendTwcc()) {
//其他匹配条件立即发送twcc
onSendTwcc();
}
}
bool TwccContext::checkIfNeedSendTwcc() const {
auto size = _rtp_recv_status.size();
if (!size) {
return false;
}
if (size >= kMaxSeqDelta) {
return true;
}
auto delta_ms = _max_stamp - _min_stamp;
if (delta_ms >= kMaxTimeDelta) {
return true;
}
return false;
}
int TwccContext::checkSeqStatus(uint16_t twcc_ext_seq) const {
if (_rtp_recv_status.empty()) {
return (int) ExtSeqStatus::normal;
}
auto max = _rtp_recv_status.rbegin()->first;
if (max > 0xFF00 && twcc_ext_seq < 0xFF) {
//发生回环了
TraceL << "rtp twcc ext seq looped:" << max << " -> " << twcc_ext_seq;
return (int) ExtSeqStatus::looped;
}
if (twcc_ext_seq - max > 0xFFFF / 2) {
TraceL << "rtp twcc ext seq jumped:" << max << " -> " << twcc_ext_seq;
return (int) ExtSeqStatus::jumped;
}
return (int) ExtSeqStatus::normal;
}
void TwccContext::onSendTwcc() {
auto max = _rtp_recv_status.rbegin()->first;
auto begin = _rtp_recv_status.begin();
auto min = begin->first;
auto ref_time = begin->second;
DebugL << "base_seq:" << min << ",pkt_status_count:" << max + 1 - min << ",ref time:" << ref_time / 64
<< ", fb count:" << (int) (_twcc_pkt_count++);
for (auto i = min; i <= max; ++i) {
auto it = _rtp_recv_status.find(i);
if (it == _rtp_recv_status.end()) {
DebugL << "rtp seq:" << i << ",packet status:" << 0 /*not recved*/ << ",delta_ms:" << 0;
} else {
auto delta_ms = it->second - ref_time;
DebugL << "rtp seq:" << i << ",packet status:" << 1 /*recved*/ << ",delta_ms:" << delta_ms;
}
}
clearStatus();
}
void TwccContext::clearStatus() {
_rtp_recv_status.clear();
_min_stamp = 0;
}