Older/MediaServer/Common/PacketCache.h

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2024-09-28 23:55:00 +08:00
/*
* Copyright (c) 2016-present 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-like 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.
*/
#ifndef ZLMEDIAKIT_PACKET_CACHE_H_
#define ZLMEDIAKIT_PACKET_CACHE_H_
#include "Common/config.h"
#include "Util/List.h"
namespace mediakit {
// / 缓存刷新策略类 [AUTO-TRANSLATED:bd941d15]
// / Cache refresh strategy class
class FlushPolicy {
public:
bool isFlushAble(bool is_video, bool is_key, uint64_t new_stamp, size_t cache_size);
private:
// 音视频的最后时间戳 [AUTO-TRANSLATED:957d18ed]
// Last timestamp of audio and video
uint64_t _last_stamp[2] = { 0, 0 };
};
// / 合并写缓存模板 [AUTO-TRANSLATED:25cde944]
// / Merge write cache template
// / \tparam packet 包类型 [AUTO-TRANSLATED:43085d9b]
// / \tparam packet Packet type
// / \tparam policy 刷新缓存策略 [AUTO-TRANSLATED:c5ac29a7]
// / \tparam policy Refresh cache strategy
// / \tparam packet_list 包缓存类型 [AUTO-TRANSLATED:a434e7fe]
// / \tparam packet_list Packet cache type
template<typename packet, typename policy = FlushPolicy, typename packet_list = toolkit::List<std::shared_ptr<packet> > >
class PacketCache {
public:
PacketCache() { _cache = std::make_shared<packet_list>(); }
virtual ~PacketCache() = default;
void inputPacket(uint64_t stamp, bool is_video, std::shared_ptr<packet> pkt, bool key_pos) {
bool flag = flushImmediatelyWhenCloseMerge();
if (!flag && _policy.isFlushAble(is_video, key_pos, stamp, _cache->size())) {
flush();
}
// 追加数据到最后 [AUTO-TRANSLATED:e24ccfb6]
// Append data to the end
_cache->emplace_back(std::move(pkt));
if (key_pos) {
_key_pos = key_pos;
}
if (flag) {
flush();
}
}
void flush() {
if (_cache->empty()) {
return;
}
onFlush(std::move(_cache), _key_pos);
_cache = std::make_shared<packet_list>();
_key_pos = false;
}
virtual void clearCache() {
_cache->clear();
}
virtual void onFlush(std::shared_ptr<packet_list>, bool key_pos) = 0;
private:
bool flushImmediatelyWhenCloseMerge() {
// 一般的协议关闭合并写时立即刷新缓存这样可以减少一帧的延时但是rtp例外 [AUTO-TRANSLATED:54eba701]
// Generally, when the protocol closes the merge write, the cache is refreshed immediately, which can reduce the delay of one frame, but RTP is an exception.
// 因为rtp的包很小一个RtpPacket包中也不是完整的一帧图像所以在关闭合并写时 [AUTO-TRANSLATED:b219082d]
// Because the RTP packet is very small, and a RtpPacket does not contain a complete frame of image, so when closing the merge write,
// 还是有必要缓冲一帧的rtp(也就是时间戳相同的rtp)再输出,这样虽然会增加一帧的延时 [AUTO-TRANSLATED:27c7ee8b]
// It is still necessary to buffer one frame of RTP (that is, RTP with the same timestamp) before outputting. Although this will increase the delay of one frame,
// 但是却对性能提升很大,这样做还是比较划算的 [AUTO-TRANSLATED:80eab719]
// But it greatly improves performance, so it is still worthwhile to do so.
GET_CONFIG(int, mergeWriteMS, General::kMergeWriteMS);
GET_CONFIG(int, rtspLowLatency, Rtsp::kLowLatency);
return std::is_same<packet, RtpPacket>::value ? rtspLowLatency : (mergeWriteMS <= 0);
}
private:
bool _key_pos = false;
policy _policy;
std::shared_ptr<packet_list> _cache;
};
}
#endif //ZLMEDIAKIT_PACKET_CACHE_H_