ZLMediaKit/src/Rtsp/RtspMediaSource.h

/*
 * 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.
 */

#ifndef SRC_RTSP_RTSPMEDIASOURCE_H_
#define SRC_RTSP_RTSPMEDIASOURCE_H_

#include <mutex>
#include <string>
#include <memory>
#include <functional>
#include <unordered_map>
#include "Common/config.h"
#include "Common/MediaSource.h"
#include "RtpCodec.h"
#include "Util/logger.h"
#include "Util/RingBuffer.h"
#include "Util/TimeTicker.h"
#include "Util/ResourcePool.h"
#include "Util/NoticeCenter.h"
#include "Thread/ThreadPool.h"
using namespace std;
using namespace toolkit;

#define RTP_GOP_SIZE 2048

namespace mediakit {

/**
 * rtsp媒体源的数据抽象
 * rtsp有关键的两要素，分别是sdp、rtp包
 * 只要生成了这两要素，那么要实现rtsp推流、rtsp服务器就很简单了
 * rtsp推拉流协议中，先传递sdp，然后再协商传输方式(tcp/udp/组播)，最后一直传递rtp
 */
class RtspMediaSource : public MediaSource, public RingDelegate<RtpPacket::Ptr> {
public:
    typedef ResourcePool<RtpPacket> PoolType;
    typedef std::shared_ptr<RtspMediaSource> Ptr;
    typedef RingBuffer<RtpPacket::Ptr> RingType;

    /**
     * 构造函数
     * @param vhost 虚拟主机名
     * @param app 应用名
     * @param stream_id 流id
     * @param ring_size 可以设置固定的环形缓冲大小，0则自适应
     */
    RtspMediaSource(const string &vhost,
                    const string &app,
                    const string &stream_id,
                    int ring_size = RTP_GOP_SIZE) :
            MediaSource(RTSP_SCHEMA, vhost, app, stream_id), _ring_size(ring_size) {}

    virtual ~RtspMediaSource() {}

    /**
     * 获取媒体源的环形缓冲
     */
    const RingType::Ptr &getRing() const {
        return _ring;
    }

    /**
     * 获取播放器个数
     */
    int readerCount() override {
        return _ring ? _ring->readerCount() : 0;
    }

    /**
     * 获取该源的sdp
     */
    const string &getSdp() const {
        return _sdp;
    }

    /**
     * 获取相应轨道的ssrc
     */
    virtual uint32_t getSsrc(TrackType trackType) {
        auto track = _sdp_parser.getTrack(trackType);
        if (!track) {
            return 0;
        }
        return track->_ssrc;
    }

    /**
     * 获取相应轨道的seqence
     */
    virtual uint16_t getSeqence(TrackType trackType) {
        auto track = _sdp_parser.getTrack(trackType);
        if (!track) {
            return 0;
        }
        return track->_seq;
    }

    /**
     * 获取相应轨道的时间戳，单位毫秒
     */
    uint32_t getTimeStamp(TrackType trackType) override {
        auto track = _sdp_parser.getTrack(trackType);
        if (track) {
            return track->_time_stamp;
        }
        auto tracks = _sdp_parser.getAvailableTrack();
        switch (tracks.size()) {
            case 0:
                return 0;
            case 1:
                return tracks[0]->_time_stamp;
            default:
                return MIN(tracks[0]->_time_stamp, tracks[1]->_time_stamp);
        }
    }

    /**
     * 更新时间戳
     */
     void setTimeStamp(uint32_t uiStamp) override {
        auto tracks = _sdp_parser.getAvailableTrack();
        for (auto &track : tracks) {
            track->_time_stamp = uiStamp;
        }
    }

    /**
     * 设置sdp
     */
    virtual void setSdp(const string &sdp) {
        _sdp = sdp;
        _sdp_parser.load(sdp);
        _have_video = (bool)_sdp_parser.getTrack(TrackVideo);
        if (_ring) {
            regist();
        }
    }

    /**
     * 输入rtp
     * @param rtp rtp包
     * @param keyPos 该包是否为关键帧的第一个包
     */
    void onWrite(const RtpPacket::Ptr &rtp, bool keyPos) override {
        auto track = _sdp_parser.getTrack(rtp->type);
        if (track) {
            track->_seq = rtp->sequence;
            track->_time_stamp = rtp->timeStamp;
            track->_ssrc = rtp->ssrc;
        }
        if (!_ring) {
            weak_ptr<RtspMediaSource> weakSelf = dynamic_pointer_cast<RtspMediaSource>(shared_from_this());
            auto lam = [weakSelf](const EventPoller::Ptr &, int size, bool) {
                auto strongSelf = weakSelf.lock();
                if (!strongSelf) {
                    return;
                }
                strongSelf->onReaderChanged(size);
            };
            //rtp包缓存最大允许2048个，大概最多3MB数据
            //但是这个是GOP缓存的上限值，真实的GOP缓存大小等于两个I帧之间的包数的两倍
            //而且每次遇到I帧，则会清空GOP缓存，所以真实的GOP缓存远小于此值
            _ring = std::make_shared<RingType>(_ring_size, std::move(lam));
            onReaderChanged(0);
            if (!_sdp.empty()) {
                regist();
            }
        }
        //不存在视频，为了减少缓存延时，那么关闭GOP缓存
        _ring->write(rtp, _have_video ? keyPos : true);
    }
private:
    /**
     * 每次增减消费者都会触发该函数
     */
    void onReaderChanged(int size) {
        if (size == 0) {
            onNoneReader();
        }
    }
private:
    int _ring_size;
    bool _have_video = false;
    SdpParser _sdp_parser;
    string _sdp;
    RingType::Ptr _ring;
};

} /* namespace mediakit */

#endif /* SRC_RTSP_RTSPMEDIASOURCE_H_ */