ZLMediaKit/src/Common/MediaSink.cpp

/*
 * Copyright (c) 2016 The ZLMediaKit project authors. All Rights Reserved.
 *
 * This file is part of ZLMediaKit(https://github.com/xia-chu/ZLMediaKit).
 *
 * Use of this source code is governed by MIT 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.
 */

#include "MediaSink.h"
#include "Extension/AAC.h"

//最多等待未初始化的Track 10秒，超时之后会忽略未初始化的Track
static size_t constexpr kMaxWaitReadyMS= 10000;

//如果直播流只有单Track，最多等待3秒，超时后未收到其他Track的数据，则认为是单Track
static size_t constexpr kMaxAddTrackMS = 3000;

//如果track未就绪，我们先缓存帧数据，但是有最大个数限制(100帧时大约4秒)，防止内存溢出
static size_t constexpr kMaxUnreadyFrame = 100;

namespace mediakit{

bool MediaSink::addTrack(const Track::Ptr &track_in) {
    GET_CONFIG(bool, enabel_audio, General::kEnableAudio);
    if (!enabel_audio) {
        //关闭音频时，加快单视频流注册速度
        _max_track_size = 1;
        if (track_in->getTrackType() == TrackAudio) {
            //音频被全局忽略
            return false;
        }
    } else {
        //是否添加静音音频
        GET_CONFIG(bool, addMuteAudio, General::kAddMuteAudio);
        if (addMuteAudio && track_in->getTrackType() == TrackVideo) {
            addMuteAudioTrack();
        }
    }
    lock_guard<recursive_mutex> lck(_mtx);
    if (_all_track_ready) {
        WarnL << "all track is ready, add this track too late!";
        return false;
    }
    //克隆Track，只拷贝其数据，不拷贝其数据转发关系
    auto track = track_in->clone();
    auto track_type = track->getTrackType();
    if (track_type == TrackAudio) {
        //确保添加非静音音频track时，取消之前的静音音频track
        _mute_audio_maker = nullptr;
    }
    _track_map[track_type] = track;
    _track_ready_callback[track_type] = [this, track]() {
        onTrackReady(track);
    };
    _ticker.resetTime();

    track->addDelegate(std::make_shared<FrameWriterInterfaceHelper>([this](const Frame::Ptr &frame) {
        if (_all_track_ready) {
            return onTrackFrame(frame);
        }
        auto &frame_unread = _frame_unread[frame->getTrackType()];
        if (frame_unread.size() > kMaxUnreadyFrame) {
            //未就绪的的track，不能缓存太多的帧，否则可能内存溢出
            frame_unread.clear();
            WarnL << "cached frame of unready track(" << frame->getCodecName() << ") is too much, now cleared";
        }
        //还有Track未就绪，先缓存之
        frame_unread.emplace_back(Frame::getCacheAbleFrame(frame));
        return true;
    }));
    return true;
}

void MediaSink::resetTracks() {
    lock_guard<recursive_mutex> lck(_mtx);
    _all_track_ready = false;
    _track_map.clear();
    _track_ready_callback.clear();
    _ticker.resetTime();
    _max_track_size = 2;
    _frame_unread.clear();
}

bool MediaSink::inputFrame(const Frame::Ptr &frame) {
    lock_guard<recursive_mutex> lck(_mtx);
    auto it = _track_map.find(frame->getTrackType());
    if (it == _track_map.end()) {
        return false;
    }
    auto ret = it->second->inputFrame(frame);
    if (_mute_audio_maker && frame->getTrackType() == TrackVideo) {
        //视频驱动产生静音音频
        _mute_audio_maker->inputFrame(frame);
    }
    checkTrackIfReady(nullptr);
    return ret;
}

void MediaSink::checkTrackIfReady_l(const Track::Ptr &track){
    //Track由未就绪状态转换成就绪状态，我们就触发onTrackReady回调
    auto it_callback = _track_ready_callback.find(track->getTrackType());
    if (it_callback != _track_ready_callback.end() && track->ready()) {
        it_callback->second();
        _track_ready_callback.erase(it_callback);
    }
}

void MediaSink::checkTrackIfReady(const Track::Ptr &track){
    if (!_all_track_ready && !_track_ready_callback.empty()) {
        if (track) {
            checkTrackIfReady_l(track);
        } else {
            for (auto &pr : _track_map) {
                checkTrackIfReady_l(pr.second);
            }
        }
    }

    if(!_all_track_ready){
        if(_ticker.elapsedTime() > kMaxWaitReadyMS){
            //如果超过规定时间，那么不再等待并忽略未准备好的Track
            emitAllTrackReady();
            return;
        }

        if(!_track_ready_callback.empty()){
            //在超时时间内，如果存在未准备好的Track，那么继续等待
            return;
        }

        if(_track_map.size() == _max_track_size){
            //如果已经添加了音视频Track，并且不存在未准备好的Track，那么说明所有Track都准备好了
            emitAllTrackReady();
            return;
        }

        if(_track_map.size() == 1 && _ticker.elapsedTime() > kMaxAddTrackMS){
            //如果只有一个Track，那么在该Track添加后，我们最多还等待若干时间(可能后面还会添加Track)
            emitAllTrackReady();
            return;
        }
    }
}

void MediaSink::addTrackCompleted(){
    lock_guard<recursive_mutex> lck(_mtx);
    _max_track_size = _track_map.size();
    checkTrackIfReady(nullptr);
}

void MediaSink::emitAllTrackReady() {
    if (_all_track_ready) {
        return;
    }

    DebugL << "all track ready use " << _ticker.elapsedTime() << "ms";
    if (!_track_ready_callback.empty()) {
        //这是超时强制忽略未准备好的Track
        _track_ready_callback.clear();
        //移除未准备好的Track
        for (auto it = _track_map.begin(); it != _track_map.end();) {
            if (!it->second->ready()) {
                WarnL << "track not ready for a long time, ignored: " << it->second->getCodecName();
                it = _track_map.erase(it);
                continue;
            }
            ++it;
        }
    }

    if (!_track_map.empty()) {
        //最少有一个有效的Track
        _all_track_ready = true;
        onAllTrackReady();

        //全部Track就绪，我们一次性把之前的帧输出
        for(auto &pr : _frame_unread){
            if (_track_map.find(pr.first) == _track_map.end()) {
                //该Track已经被移除
                continue;
            }
            pr.second.for_each([&](const Frame::Ptr &frame) {
                onTrackFrame(frame);
            });
        }
        _frame_unread.clear();
    }
}

vector<Track::Ptr> MediaSink::getTracks(bool trackReady) const{
    vector<Track::Ptr> ret;
    lock_guard<recursive_mutex> lck(_mtx);
    for (auto &pr : _track_map){
        if(trackReady && !pr.second->ready()){
            continue;
        }
        ret.emplace_back(pr.second);
    }
    return ret;
}

class FrameFromStaticPtr : public FrameFromPtr {
public:
    template<typename ... ARGS>
    FrameFromStaticPtr(ARGS &&...args) : FrameFromPtr(std::forward<ARGS>(args)...) {};
    ~FrameFromStaticPtr() override = default;

    bool cacheAble() const override {
        return true;
    }
};

static uint8_t s_mute_adts[] = {0xff, 0xf1, 0x6c, 0x40, 0x2d, 0x3f, 0xfc, 0x00, 0xe0, 0x34, 0x20, 0xad, 0xf2, 0x3f, 0xb5, 0xdd,
                                0x73, 0xac, 0xbd, 0xca, 0xd7, 0x7d, 0x4a, 0x13, 0x2d, 0x2e, 0xa2, 0x62, 0x02, 0x70, 0x3c, 0x1c,
                                0xc5, 0x63, 0x55, 0x69, 0x94, 0xb5, 0x8d, 0x70, 0xd7, 0x24, 0x6a, 0x9e, 0x2e, 0x86, 0x24, 0xea,
                                0x4f, 0xd4, 0xf8, 0x10, 0x53, 0xa5, 0x4a, 0xb2, 0x9a, 0xf0, 0xa1, 0x4f, 0x2f, 0x66, 0xf9, 0xd3,
                                0x8c, 0xa6, 0x97, 0xd5, 0x84, 0xac, 0x09, 0x25, 0x98, 0x0b, 0x1d, 0x77, 0x04, 0xb8, 0x55, 0x49,
                                0x85, 0x27, 0x06, 0x23, 0x58, 0xcb, 0x22, 0xc3, 0x20, 0x3a, 0x12, 0x09, 0x48, 0x24, 0x86, 0x76,
                                0x95, 0xe3, 0x45, 0x61, 0x43, 0x06, 0x6b, 0x4a, 0x61, 0x14, 0x24, 0xa9, 0x16, 0xe0, 0x97, 0x34,
                                0xb6, 0x58, 0xa4, 0x38, 0x34, 0x90, 0x19, 0x5d, 0x00, 0x19, 0x4a, 0xc2, 0x80, 0x4b, 0xdc, 0xb7,
                                0x00, 0x18, 0x12, 0x3d, 0xd9, 0x93, 0xee, 0x74, 0x13, 0x95, 0xad, 0x0b, 0x59, 0x51, 0x0e, 0x99,
                                0xdf, 0x49, 0x98, 0xde, 0xa9, 0x48, 0x4b, 0xa5, 0xfb, 0xe8, 0x79, 0xc9, 0xe2, 0xd9, 0x60, 0xa5,
                                0xbe, 0x74, 0xa6, 0x6b, 0x72, 0x0e, 0xe3, 0x7b, 0x28, 0xb3, 0x0e, 0x52, 0xcc, 0xf6, 0x3d, 0x39,
                                0xb7, 0x7e, 0xbb, 0xf0, 0xc8, 0xce, 0x5c, 0x72, 0xb2, 0x89, 0x60, 0x33, 0x7b, 0xc5, 0xda, 0x49,
                                0x1a, 0xda, 0x33, 0xba, 0x97, 0x9e, 0xa8, 0x1b, 0x6d, 0x5a, 0x77, 0xb6, 0xf1, 0x69, 0x5a, 0xd1,
                                0xbd, 0x84, 0xd5, 0x4e, 0x58, 0xa8, 0x5e, 0x8a, 0xa0, 0xc2, 0xc9, 0x22, 0xd9, 0xa5, 0x53, 0x11,
                                0x18, 0xc8, 0x3a, 0x39, 0xcf, 0x3f, 0x57, 0xb6, 0x45, 0x19, 0x1e, 0x8a, 0x71, 0xa4, 0x46, 0x27,
                                0x9e, 0xe9, 0xa4, 0x86, 0xdd, 0x14, 0xd9, 0x4d, 0xe3, 0x71, 0xe3, 0x26, 0xda, 0xaa, 0x17, 0xb4,
                                0xac, 0xe1, 0x09, 0xc1, 0x0d, 0x75, 0xba, 0x53, 0x0a, 0x37, 0x8b, 0xac, 0x37, 0x39, 0x41, 0x27,
                                0x6a, 0xf0, 0xe9, 0xb4, 0xc2, 0xac, 0xb0, 0x39, 0x73, 0x17, 0x64, 0x95, 0xf4, 0xdc, 0x33, 0xbb,
                                0x84, 0x94, 0x3e, 0xf8, 0x65, 0x71, 0x60, 0x7b, 0xd4, 0x5f, 0x27, 0x79, 0x95, 0x6a, 0xba, 0x76,
                                0xa6, 0xa5, 0x9a, 0xec, 0xae, 0x55, 0x3a, 0x27, 0x48, 0x23, 0xcf, 0x5c, 0x4d, 0xbc, 0x0b, 0x35,
                                0x5c, 0xa7, 0x17, 0xcf, 0x34, 0x57, 0xc9, 0x58, 0xc5, 0x20, 0x09, 0xee, 0xa5, 0xf2, 0x9c, 0x6c,
                                0x39, 0x1a, 0x77, 0x92, 0x9b, 0xff, 0xc6, 0xae, 0xf8, 0x36, 0xba, 0xa8, 0xaa, 0x6b, 0x1e, 0x8c,
                                0xc5, 0x97, 0x39, 0x6a, 0xb8, 0xa2, 0x55, 0xa8, 0xf8};

#define MUTE_ADTS_DATA s_mute_adts
#define MUTE_ADTS_DATA_LEN sizeof(s_mute_adts)
#define MUTE_ADTS_DATA_MS 130

bool MuteAudioMaker::inputFrame(const Frame::Ptr &frame) {
    if (frame->getTrackType() == TrackVideo) {
        auto audio_idx = frame->dts() / MUTE_ADTS_DATA_MS;
        if (_audio_idx != audio_idx) {
            _audio_idx = audio_idx;
            auto aacFrame = std::make_shared<FrameFromStaticPtr>(CodecAAC, (char *) MUTE_ADTS_DATA, MUTE_ADTS_DATA_LEN,
                                                                 _audio_idx * MUTE_ADTS_DATA_MS, 0, ADTS_HEADER_LEN);
            return FrameDispatcher::inputFrame(aacFrame);
        }
    }
    return false;
}

bool MediaSink::addMuteAudioTrack() {
    if (getTrack(TrackAudio, false)) {
        WarnL << "audio track already existed";
        return false;
    }
    if (addTrack(std::make_shared<AACTrack>())) {
        _mute_audio_maker = std::make_shared<MuteAudioMaker>();
        _mute_audio_maker->addDelegate(std::make_shared<FrameWriterInterfaceHelper>([this](const Frame::Ptr &frame) {
            return inputFrame(frame);
        }));
        return true;
    }
    return false;
}


}//namespace mediakit