mirror of
https://github.com/ZLMediaKit/ZLMediaKit.git
synced 2024-10-30 16:27:36 +08:00
124 lines
3.9 KiB
C++
124 lines
3.9 KiB
C++
/*
|
||
* 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"
|
||
#include "Rtcp/RtcpFCI.h"
|
||
|
||
using namespace mediakit;
|
||
|
||
enum class ExtSeqStatus : int {
|
||
normal = 0,
|
||
looped,
|
||
jumped,
|
||
};
|
||
|
||
void TwccContext::onRtp(uint32_t ssrc, uint16_t twcc_ext_seq, uint64_t stamp_ms) {
|
||
switch ((ExtSeqStatus) checkSeqStatus(twcc_ext_seq)) {
|
||
case ExtSeqStatus::jumped: /*seq异常,过滤掉*/ return;
|
||
case ExtSeqStatus::looped: /*回环，触发发送twcc rtcp*/ onSendTwcc(ssrc); break;
|
||
case ExtSeqStatus::normal: break;
|
||
default: /*不可达*/assert(0); break;
|
||
}
|
||
|
||
auto result = _rtp_recv_status.emplace(twcc_ext_seq, stamp_ms);
|
||
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 (needSendTwcc()) {
|
||
//其他匹配条件立即发送twcc
|
||
onSendTwcc(ssrc);
|
||
}
|
||
}
|
||
|
||
bool TwccContext::needSendTwcc() const {
|
||
if (_rtp_recv_status.empty()) {
|
||
return false;
|
||
}
|
||
return (_rtp_recv_status.size() >= kMaxSeqSize) || (_max_stamp - _min_stamp >= kMaxTimeDelta);
|
||
}
|
||
|
||
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;
|
||
auto delta = (int32_t) twcc_ext_seq - (int32_t) max;
|
||
if (delta > 0 && delta < 0xFFFF / 2) {
|
||
//正常增长
|
||
return (int) ExtSeqStatus::normal;
|
||
}
|
||
if (delta < -0xFF00) {
|
||
//回环
|
||
TraceL << "rtp twcc ext seq looped:" << max << " -> " << twcc_ext_seq;
|
||
return (int) ExtSeqStatus::looped;
|
||
}
|
||
if (delta > 0xFF00) {
|
||
//回环后收到前面大的乱序的包，无法处理，丢弃
|
||
TraceL << "rtp twcc ext seq jumped after looped:" << max << " -> " << twcc_ext_seq;
|
||
return (int) ExtSeqStatus::jumped;
|
||
}
|
||
auto min = _rtp_recv_status.begin()->first;
|
||
if (min <= twcc_ext_seq || twcc_ext_seq <= max) {
|
||
//正常回退
|
||
return (int) ExtSeqStatus::normal;
|
||
}
|
||
//seq莫名的大幅增加或减少，无法处理，丢弃
|
||
TraceL << "rtp twcc ext seq jumped:" << max << " -> " << twcc_ext_seq;
|
||
return (int) ExtSeqStatus::jumped;
|
||
}
|
||
|
||
void TwccContext::onSendTwcc(uint32_t ssrc) {
|
||
auto max = _rtp_recv_status.rbegin()->first;
|
||
auto begin = _rtp_recv_status.begin();
|
||
auto min = begin->first;
|
||
//参考时间戳的最小单位是64ms
|
||
auto ref_time = begin->second >> 6;
|
||
//还原基准时间戳
|
||
auto last_time = ref_time << 6;
|
||
FCI_TWCC::TwccPacketStatus status;
|
||
for (auto seq = min; seq <= max; ++seq) {
|
||
int16_t delta = 0;
|
||
SymbolStatus symbol = SymbolStatus::not_received;
|
||
auto it = _rtp_recv_status.find(seq);
|
||
if (it != _rtp_recv_status.end()) {
|
||
//recv delta,单位为250us,1ms等于4x250us
|
||
delta = (int16_t) (4 * ((int64_t) it->second - (int64_t) last_time));
|
||
if (delta < 0 || delta > 0xFF) {
|
||
symbol = SymbolStatus::large_delta;
|
||
} else {
|
||
symbol = SymbolStatus::small_delta;
|
||
}
|
||
last_time = it->second;
|
||
}
|
||
status.emplace(seq, std::make_pair(symbol, delta));
|
||
}
|
||
auto fci = FCI_TWCC::create(ref_time, _twcc_pkt_count++, status);
|
||
if (_cb) {
|
||
_cb(ssrc, std::move(fci));
|
||
}
|
||
clearStatus();
|
||
}
|
||
|
||
void TwccContext::clearStatus() {
|
||
_rtp_recv_status.clear();
|
||
_min_stamp = 0;
|
||
}
|
||
|
||
void TwccContext::setOnSendTwccCB(TwccContext::onSendTwccCB cb) {
|
||
_cb = std::move(cb);
|
||
}
|