ZLMediaKit/src/Http/TsplayerImp.cpp

#include "TsPlayerImp.h"

namespace mediakit {
    void TsDemuxer::start(const EventPoller::Ptr &poller, TrackListener *listener) {
        _frame_cache.clear();
        _stamp[TrackAudio].setRelativeStamp(0);
        _stamp[TrackVideo].setRelativeStamp(0);
        _stamp[TrackAudio].syncTo(_stamp[TrackVideo]);
        setPlayPosition(0);

        _delegate.setTrackListener(listener);

        //每50毫秒执行一次
        weak_ptr<TsDemuxer> weak_self = shared_from_this();
        _timer = std::make_shared<Timer>(0.05f, [weak_self]() {
            auto strong_self = weak_self.lock();
            if (!strong_self) {
                return false;
            }
            strong_self->onTick();
            return true;
        }, poller);
    }

    bool TsDemuxer::inputFrame(const Frame::Ptr &frame) {
        //为了避免track准备时间过长, 因此在没准备好之前, 直接消费掉所有的帧
        if (!_delegate.isAllTrackReady()) {
            _delegate.inputFrame(frame);
            return true;
        }
        //计算相对时间戳
        int64_t dts, pts;
        //根据时间戳缓存frame
        _stamp[frame->getTrackType()].revise(frame->dts(), frame->pts(), dts, pts);
        _frame_cache.emplace(dts, Frame::getCacheAbleFrame(frame));
        //根据时间戳缓存frame
//    _frame_cache.emplace(dts, Frame::getCacheAbleFrame(frame));

        if (getBufferMS() > 30 * 1000) {
            //缓存超过30秒，强制消费至15秒(减少延时或内存占用)
            while (getBufferMS() > 15 * 1000) {
                _delegate.inputFrame(_frame_cache.begin()->second);
                _frame_cache.erase(_frame_cache.begin());
            }
            //接着播放缓存中最早的帧
            setPlayPosition(_frame_cache.begin()->first);
        }
        return true;
    }

    int64_t TsDemuxer::getPlayPosition() {
        return _ticker.elapsedTime() + _ticker_offset;
    }

    int64_t TsDemuxer::getBufferMS() {
        if (_frame_cache.empty()) {
            return 0;
        }
        return _frame_cache.rbegin()->first - _frame_cache.begin()->first;
    }

    void TsDemuxer::setPlayPosition(int64_t pos) {
        _ticker.resetTime();
        _ticker_offset = pos;
    }

    void TsDemuxer::onTick() {
        auto it = _frame_cache.begin();
        while (it != _frame_cache.end()) {
            if (it->first > getPlayPosition()) {
                //这些帧还未到时间播放
                break;
            }
            if (getBufferMS() < 3 * 1000) {
                //缓存小于3秒,那么降低定时器消费速度(让剩余的数据在3秒后消费完毕)
                //目的是为了防止定时器长时间干等后，数据瞬间消费完毕
                setPlayPosition(_frame_cache.begin()->first);
            }
            //消费掉已经到期的帧
            _delegate.inputFrame(it->second);
            it = _frame_cache.erase(it);
        }
    }

//////////////////////////////////////////////////////////////////////////

    TsPlayerImp::TsPlayerImp(const EventPoller::Ptr &poller) : PlayerImp<TsPlayer, PlayerBase>(poller) {}

    void TsPlayerImp::onPacket(const char *data, size_t len) {
        if (!_decoder) {
            _decoder = DecoderImp::createDecoder(DecoderImp::decoder_ts, _demuxer.get());
        }

        if (_decoder && _demuxer) {
            _decoder->input((uint8_t *) data, len);
        }
    }

    void TsPlayerImp::addTrackCompleted() {
        PlayerImp<TsPlayer, PlayerBase>::onPlayResult(SockException(Err_success, "play hls success"));
    }

    void TsPlayerImp::onPlayResult(const SockException &ex) {
        WarnL << ex.getErrCode() << " " << ex.what();
        if (ex) {
            PlayerImp<TsPlayer, PlayerBase>::onPlayResult(ex);
        } else {
            auto demuxer = std::make_shared<TsDemuxer>();
            demuxer->start(getPoller(), this);
            _demuxer = std::move(demuxer);
        }
    }

    void TsPlayerImp::onShutdown(const SockException &ex) {
        PlayerImp<TsPlayer, PlayerBase>::onShutdown(ex);
        _demuxer = nullptr;
    }

    vector<Track::Ptr> TsPlayerImp::getTracks(bool ready) const {
        return static_pointer_cast<TsDemuxer>(_demuxer)->getTracks(ready);
    }

}//namespace mediakit