mirror of
https://github.com/ZLMediaKit/ZLMediaKit.git
synced 2024-10-31 00:37:39 +08:00
244 lines
6.7 KiB
C++
244 lines
6.7 KiB
C++
/*
|
||
* Copyright (c) 2016 The ZLMediaKit project authors. All Rights Reserved.
|
||
*
|
||
* This file is part of ZLMediaKit(https://github.com/ZLMediaKit/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 "Nack.h"
|
||
|
||
static constexpr uint32_t kMaxNackMS = 10 * 1000;
|
||
|
||
void NackList::push_back(RtpPacket::Ptr rtp) {
|
||
auto seq = rtp->getSeq();
|
||
_nack_cache_seq.emplace_back(seq);
|
||
_nack_cache_pkt.emplace(seq, std::move(rtp));
|
||
while (get_cache_ms() > kMaxNackMS) {
|
||
//需要清除部分nack缓存
|
||
pop_front();
|
||
}
|
||
}
|
||
|
||
void NackList::for_each_nack(const FCI_NACK &nack, const function<void(const RtpPacket::Ptr &rtp)> &func) {
|
||
auto seq = nack.getPid();
|
||
for (auto bit : nack.getBitArray()) {
|
||
if (bit) {
|
||
//丢包
|
||
RtpPacket::Ptr *ptr = get_rtp(seq);
|
||
if (ptr) {
|
||
func(*ptr);
|
||
}
|
||
}
|
||
++seq;
|
||
}
|
||
}
|
||
|
||
void NackList::pop_front() {
|
||
if (_nack_cache_seq.empty()) {
|
||
return;
|
||
}
|
||
_nack_cache_pkt.erase(_nack_cache_seq.front());
|
||
_nack_cache_seq.pop_front();
|
||
}
|
||
|
||
RtpPacket::Ptr *NackList::get_rtp(uint16_t seq) {
|
||
auto it = _nack_cache_pkt.find(seq);
|
||
if (it == _nack_cache_pkt.end()) {
|
||
return nullptr;
|
||
}
|
||
return &it->second;
|
||
}
|
||
|
||
uint32_t NackList::get_cache_ms() {
|
||
if (_nack_cache_seq.size() < 2) {
|
||
return 0;
|
||
}
|
||
uint32_t back = _nack_cache_pkt[_nack_cache_seq.back()]->getStampMS();
|
||
uint32_t front = _nack_cache_pkt[_nack_cache_seq.front()]->getStampMS();
|
||
if (back >= front) {
|
||
return back - front;
|
||
}
|
||
//很有可能回环了
|
||
return back + (UINT32_MAX - front);
|
||
}
|
||
|
||
////////////////////////////////////////////////////////////////////////////////////////////////
|
||
|
||
void NackContext::received(uint16_t seq, bool is_rtx) {
|
||
if (!_last_max_seq && _seq.empty()) {
|
||
_last_max_seq = seq - 1;
|
||
}
|
||
if (is_rtx || (seq < _last_max_seq && !(seq < 1024 && _last_max_seq > UINT16_MAX - 1024))) {
|
||
//重传包或
|
||
//seq回退，且非回环，那么这个应该是重传包
|
||
onRtx(seq);
|
||
return;
|
||
}
|
||
|
||
_seq.emplace(seq);
|
||
auto max_seq = *_seq.rbegin();
|
||
auto min_seq = *_seq.begin();
|
||
auto diff = max_seq - min_seq;
|
||
if (!diff) {
|
||
return;
|
||
}
|
||
|
||
if (diff > UINT16_MAX / 2) {
|
||
//回环
|
||
_seq.clear();
|
||
_last_max_seq = min_seq;
|
||
_nack_send_status.clear();
|
||
return;
|
||
}
|
||
|
||
if (_seq.size() == diff + 1 && _last_max_seq + 1 == min_seq) {
|
||
//都是连续的seq，未丢包
|
||
_seq.clear();
|
||
_last_max_seq = max_seq;
|
||
} else {
|
||
//seq不连续，有丢包
|
||
if (min_seq == _last_max_seq + 1) {
|
||
//前面部分seq是连续的，未丢包，移除之
|
||
eraseFrontSeq();
|
||
}
|
||
|
||
//有丢包，丢包从_last_max_seq开始
|
||
auto nack_rtp_count = FCI_NACK::kBitSize;
|
||
if (max_seq - _last_max_seq > nack_rtp_count) {
|
||
vector<bool> vec;
|
||
vec.resize(FCI_NACK::kBitSize, false);
|
||
for (auto i = 0; i < nack_rtp_count; ++i) {
|
||
vec[i] = _seq.find(_last_max_seq + i + 2) == _seq.end();
|
||
}
|
||
doNack(FCI_NACK(_last_max_seq + 1, vec), true);
|
||
_last_max_seq += nack_rtp_count + 1;
|
||
if (_last_max_seq >= max_seq) {
|
||
_seq.clear();
|
||
} else {
|
||
auto it = _seq.emplace_hint(_seq.begin(), _last_max_seq + 1);
|
||
_seq.erase(_seq.begin(), it);
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
void NackContext::setOnNack(onNack cb) {
|
||
_cb = std::move(cb);
|
||
}
|
||
|
||
void NackContext::doNack(const FCI_NACK &nack, bool record_nack) {
|
||
if (record_nack) {
|
||
recordNack(nack);
|
||
}
|
||
if (_cb) {
|
||
_cb(nack);
|
||
}
|
||
}
|
||
|
||
void NackContext::eraseFrontSeq() {
|
||
//前面部分seq是连续的，未丢包，移除之
|
||
for (auto it = _seq.begin(); it != _seq.end();) {
|
||
if (*it != _last_max_seq + 1) {
|
||
//seq不连续，丢包了
|
||
break;
|
||
}
|
||
_last_max_seq = *it;
|
||
it = _seq.erase(it);
|
||
}
|
||
}
|
||
|
||
void NackContext::onRtx(uint16_t seq) {
|
||
auto it = _nack_send_status.find(seq);
|
||
if (it == _nack_send_status.end()) {
|
||
return;
|
||
}
|
||
auto rtt = getCurrentMillisecond() - it->second.update_stamp;
|
||
_nack_send_status.erase(it);
|
||
|
||
if (rtt >= 0) {
|
||
//rtt不肯小于0
|
||
_rtt = rtt;
|
||
//InfoL << "rtt:" << rtt;
|
||
}
|
||
}
|
||
|
||
void NackContext::recordNack(const FCI_NACK &nack) {
|
||
auto now = getCurrentMillisecond();
|
||
auto i = nack.getPid();
|
||
for (auto flag : nack.getBitArray()) {
|
||
if (flag) {
|
||
auto &ref = _nack_send_status[i];
|
||
ref.first_stamp = now;
|
||
ref.update_stamp = now;
|
||
ref.nack_count = 1;
|
||
}
|
||
++i;
|
||
}
|
||
//记录太多了，移除一部分早期的记录
|
||
while (_nack_send_status.size() > kNackMaxSize) {
|
||
_nack_send_status.erase(_nack_send_status.begin());
|
||
}
|
||
}
|
||
|
||
uint64_t NackContext::reSendNack() {
|
||
set<uint16_t> nack_rtp;
|
||
auto now = getCurrentMillisecond();
|
||
for (auto it = _nack_send_status.begin(); it != _nack_send_status.end();) {
|
||
if (now - it->second.first_stamp > kNackMaxMS) {
|
||
//该rtp丢失太久了，不再要求重传
|
||
it = _nack_send_status.erase(it);
|
||
continue;
|
||
}
|
||
if (now - it->second.update_stamp < 2 * _rtt) {
|
||
//距离上次nack不足2倍的rtt，不用再发送nack
|
||
++it;
|
||
continue;
|
||
}
|
||
//此rtp需要请求重传
|
||
nack_rtp.emplace(it->first);
|
||
//更新nack发送时间戳
|
||
it->second.update_stamp = now;
|
||
if (++(it->second.nack_count) == kNackMaxCount) {
|
||
//nack次数太多，移除之
|
||
it = _nack_send_status.erase(it);
|
||
continue;
|
||
}
|
||
++it;
|
||
}
|
||
|
||
if (_nack_send_status.empty()) {
|
||
//不需要再发送nack
|
||
return 0;
|
||
}
|
||
|
||
int pid = -1;
|
||
vector<bool> vec;
|
||
for (auto it = nack_rtp.begin(); it != nack_rtp.end();) {
|
||
if (pid == -1) {
|
||
pid = *it;
|
||
vec.resize(FCI_NACK::kBitSize, false);
|
||
++it;
|
||
continue;
|
||
}
|
||
auto inc = *it - pid;
|
||
if (inc > FCI_NACK::kBitSize) {
|
||
//新的nack包
|
||
doNack(FCI_NACK(pid, vec), false);
|
||
pid = -1;
|
||
continue;
|
||
}
|
||
//这个包丢了
|
||
vec[inc - 1] = true;
|
||
++it;
|
||
}
|
||
if (pid != -1) {
|
||
doNack(FCI_NACK(pid, vec), false);
|
||
}
|
||
|
||
//重传间隔不得低于5ms
|
||
return std::max(_rtt, 5);
|
||
}
|