整理文件录制

src/Common/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;
+
+    if(_last_dts != dts){
+        //时间戳发生变更
+        _relativeStamp += deltaStamp(modifyStamp ? _ticker.elapsedTime() : dts);
+        _last_dts = 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