bool FFmpegSave::initVideoH264()
{
    //查找視頻編碼器(如果源頭是H265則采用HEVC作為編碼器)
    AVCodecID codecID = FFmpegHelper::getCodecID(videoStreamIn);
    if (codecID == AV_CODEC_ID_HEVC) {
        videoCodec = avcodec_find_encoder(AV_CODEC_ID_HEVC);
    } else {
        videoCodec = avcodec_find_encoder(AV_CODEC_ID_H264);
    }

    if (!videoCodec) {
        debug("編碼失敗", QString("錯誤: 查找視頻編碼器失敗"));
        return false;
    }

    //創(chuàng)建視頻編碼器上下文
    videoCodecCtx = avcodec_alloc_context3(videoCodec);
    if (!videoCodecCtx) {
        debug("編碼失敗", QString("錯誤: 創(chuàng)建視頻編碼器上下文失敗"));
        return false;
    }

    //為了兼容低版本的編譯器推薦選擇第一種方式
#if 1
    //放大系數(shù)是為了小數(shù)位能夠正確放大到整型
    int ratio = 10000;
    videoCodecCtx->time_base.num = 1 * ratio;
    videoCodecCtx->time_base.den = frameRate * ratio;
    videoCodecCtx->framerate.num = frameRate * ratio;
    videoCodecCtx->framerate.den = 1 * ratio;
#elif 0
    videoCodecCtx->time_base = {1, frameRate};
    videoCodecCtx->framerate = {frameRate, 1};
#else
    videoCodecCtx->time_base = videoStreamIn->codec->time_base;
    videoCodecCtx->framerate = videoStreamIn->codec->framerate;
#endif

#if 0
    videoCodecCtx->qmin = 10;
    videoCodecCtx->qmax = 51;
    videoCodecCtx->me_range = 16;
    videoCodecCtx->max_qdiff = 4;
    videoCodecCtx->qcompress = 0.6;
#endif

    //初始化視頻編碼器參數(shù)(如果要文件體積小一些畫質差一些可以調整碼率)
    //參數(shù)說明 https://blog.csdn.net/qq_40179458/article/details/110449653
    videoCodecCtx->bit_rate = FFmpegHelper::getBitRate(videoWidth, videoHeight);
    videoCodecCtx->width = videoWidth;
    videoCodecCtx->height = videoHeight;
    videoCodecCtx->gop_size = 25;
    videoCodecCtx->max_b_frames = 3;
    videoCodecCtx->pix_fmt = AV_PIX_FMT_YUV420P;
    videoCodecCtx->level = 50;
    videoCodecCtx->profile = FF_PROFILE_H264_MAIN;

    //加上下面這個才能在文件屬性中看到分辨率等信息 https://www.cnblogs.com/lidabo/p/15754031.html
    if (saveVideoType == SaveVideoType_Mp4) {
        videoCodecCtx->flags |= AV_CODEC_FLAG_GLOBAL_HEADER;
    }

    //加載預設 https://blog.csdn.net/JineD/article/details/125304570
    if (videoCodecCtx->codec_id == AV_CODEC_ID_H264) {
        av_opt_set(videoCodecCtx->priv_data, "preset", "slow", 0);
        //設置零延遲(本地攝像頭視頻流保存如果不設置則播放的時候會越來越模糊)
        av_opt_set(videoCodecCtx->priv_data, "tune", "zerolatency", 0);
    } else if (videoCodecCtx->codec_id == AV_CODEC_ID_HEVC) {
        av_opt_set(videoCodecCtx->priv_data, "x265-params", "qp=20", 0);
        av_opt_set(videoCodecCtx->priv_data, "preset", "ultrafast", 0);
        av_opt_set(videoCodecCtx->priv_data, "tune", "zero-latency", 0);
    }

    //打開視頻編碼器
    int result = avcodec_open2(videoCodecCtx, videoCodec, NULL);
    if (result < 0) {
        debug("打開編碼", QString("錯誤: 打開視頻編碼器失敗 %1").arg(FFmpegHelper::getError(result)));
        return false;
    }

    videoPacket = FFmpegHelper::creatPacket(NULL);
    return true;
}

bool FFmpegSave::initVideoMp4()
{
    //必須先設置過輸入視頻流
    if (!videoStreamIn || fileName.isEmpty()) {
        return false;
    }

    //有部分視頻參數(shù)不正確保存不了 http://tv.netxt.cc:1998/live/y.flv
    if (videoStreamIn->time_base.num == 0) {
        return false;
    }

    QByteArray fileData = fileName.toUtf8();
    const char *filename = fileData.data();

    //開辟一個格式上下文用來處理視頻流輸出
    int result = avformat_alloc_output_context2(&formatCtx, NULL, "mp4", filename);
    if (result < 0) {
        debug("創(chuàng)建格式", QString("錯誤: %1").arg(FFmpegHelper::getError(result)));
        return false;
    }

    //創(chuàng)建視頻流用來輸出視頻數(shù)據(jù)到文件
    videoStreamOut = avformat_new_stream(formatCtx, NULL);
    result = FFmpegHelper::copyContext(videoCodecCtx, videoStreamOut, true);
    if (result < 0) {
        debug("創(chuàng)建視頻", QString("錯誤: %1").arg(FFmpegHelper::getError(result)));
        goto end;
    }

    //打開輸出文件
    result = avio_open(&formatCtx->pb, filename, AVIO_FLAG_WRITE);
    if (result < 0) {
        debug("打開輸出", QString("錯誤: %1").arg(FFmpegHelper::getError(result)));
        goto end;
    }

    //寫入文件開始符
    result = avformat_write_header(formatCtx, NULL);
    if (result < 0) {
        debug("寫入失敗", QString("錯誤: %1").arg(FFmpegHelper::getError(result)));
        goto end;
    }

    return true;

end:
    //關閉釋放并清理文件
    this->close();
    this->deleteFile(fileName);
    return false;
}

void FFmpegSave::writePacket(AVPacket *packet)
{
    packetCount++;
    if (saveVideoType == SaveVideoType_H264) {
        file.write((char *)packet->data, packet->size);
    } else if (saveVideoType == SaveVideoType_Mp4) {
        AVRational timeBaseIn = videoStreamIn->time_base;
        AVRational timeBaseOut = videoStreamOut->time_base;

        //沒有下面這段判斷在遇到不連續(xù)的幀的時候就會錯位(相當于每次重新計算時間基準保證時間正確)
        //不連續(xù)幀的情況有暫停錄制以及切換播放進度導致中間有些幀不需要錄制
        double fps = frameRate;//av_q2d(videoStreamIn->r_frame_rate);
        double duration = AV_TIME_BASE / fps;
        packet->pts = (packetCount * duration) / (av_q2d(timeBaseIn) * AV_TIME_BASE);
        packet->dts = packet->pts;
        packet->duration = duration / (av_q2d(timeBaseIn) * AV_TIME_BASE);

        //重新調整時間基準
        packet->pts = av_rescale_q_rnd(packet->pts, timeBaseIn, timeBaseOut, (AVRounding)(AV_ROUND_NEAR_INF | AV_ROUND_PASS_MINMAX));
        packet->dts = packet->pts;
        //packet->dts = av_rescale_q_rnd(packet->dts, timeBaseIn, timeBaseOut, (AVRounding)(AV_ROUND_NEAR_INF | AV_ROUND_PASS_MINMAX));
        packet->duration = av_rescale_q(packet->duration, timeBaseIn, timeBaseOut);
        packet->pos = -1;

        //寫入一幀數(shù)據(jù)
        int result = av_interleaved_write_frame(formatCtx, packet);
        if (result < 0) {
            debug("寫入失敗", QString("錯誤: %1").arg(FFmpegHelper::getError(result)));
        }
    }

    av_packet_unref(packet);
}