ZLMediaKit/src/MediaFile/Stamp.cpp

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/*
* MIT License
*
* Copyright (c) 2016-2019 xiongziliang <771730766@qq.com>
*
* This file is part of ZLMediaKit(https://github.com/xiongziliang/ZLMediaKit).
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
#include "Stamp.h"
namespace mediakit {
int64_t DeltaStamp::deltaStamp(int64_t stamp) {
if(!_last_stamp){
//第一次计算时间戳增量,时间戳增量为0
_last_stamp = stamp;
return 0;
}
int64_t ret = stamp - _last_stamp;
if(ret >= 0){
//时间戳增量为正,返回之
_last_stamp = stamp;
return ret;
}
//时间戳增量为负,说明时间戳回环了或回退了
_last_stamp = stamp;
return _playback ? ret : 0;
}
void DeltaStamp::setPlayBack(bool playback) {
_playback = playback;
}
void Stamp::revise(int64_t dts, int64_t pts, int64_t &dts_out, int64_t &pts_out,bool modifyStamp) {
if(!pts){
//没有播放时间戳,使其赋值为解码时间戳
pts = dts;
}
//pts和dts的差值
int pts_dts_diff = pts - dts;
//相对时间戳
_relativeStamp += deltaStamp(modifyStamp ? _ticker.elapsedTime() : dts);
dts_out = _relativeStamp;
//////////////以下是播放时间戳的计算//////////////////
if(pts_dts_diff > 200 || pts_dts_diff < -200){
//如果差值大于200毫秒则认为由于回环导致时间戳错乱了
pts_dts_diff = 0;
}
pts_out = dts_out + pts_dts_diff;
if(pts_out < 0){
//时间戳不能小于0
pts_out = 0;
}
}
void Stamp::setRelativeStamp(int64_t relativeStamp) {
_relativeStamp = relativeStamp;
}
int64_t Stamp::getRelativeStamp() const {
return _relativeStamp;
}
}//namespace mediakit