static double get_sync_ipts(const OutputStream *ost)
{
    const InputStream *ist = ost->sync_ist;
    OutputFile *of = &output_files[ost->file_index];

	ost->sync_ist->pts = fabs(ost->sync_ist->pts);

	fprintf(stderr, "ist->pts:%ld, of->start_time:%ld, [ost->file_index]: %d, AV_TIME_BASE:%d\n", ist->pts, of->start_time, ost->file_index, AV_TIME_BASE);
    return (double)(ist->pts - of->start_time) / AV_TIME_BASE;
}


static void do_video_out(AVFormatContext *s,
                         OutputStream *ost,
                         InputStream *ist,
                         AVFrame *in_picture,
                         int *frame_size, float quality)
{
    int nb_frames, i, ret, format_video_sync;
    AVFrame *final_picture;
    AVCodecContext *enc;
    double sync_ipts;
    double duration = 0;

    enc = ost->st->codec;

    if (ist->st->start_time != AV_NOPTS_VALUE && ist->st->first_dts != AV_NOPTS_VALUE) {
        duration = FFMAX(av_q2d(ist->st->time_base), av_q2d(ist->st->codec->time_base));
        if(ist->st->avg_frame_rate.num)
            duration= FFMAX(duration, 1/av_q2d(ist->st->avg_frame_rate));

        duration /= av_q2d(enc->time_base);
    }

	double tmpSync_ipts = get_sync_ipts(ost);
    sync_ipts = tmpSync_ipts / av_q2d(enc->time_base);
	fprintf(stderr, "sync_ipts:%f, get_sync_ipts(ost):%f, av_q2d(enc->time_base):%f\n", sync_ipts, tmpSync_ipts, av_q2d(enc->time_base));

    /* by default, we output a single frame */
    nb_frames = 1;

    *frame_size = 0;

    format_video_sync = video_sync_method;
    if (format_video_sync == VSYNC_AUTO)
        format_video_sync = (s->oformat->flags & AVFMT_VARIABLE_FPS) ? ((s->oformat->flags & AVFMT_NOTIMESTAMPS) ? VSYNC_PASSTHROUGH : VSYNC_VFR) : 1;

    if (format_video_sync != VSYNC_PASSTHROUGH) {
        double vdelta = sync_ipts - ost->sync_opts + duration;
        // FIXME set to 0.5 after we fix some dts/pts bugs like in avidec.c
        if (vdelta < -1.1)
            nb_frames = 0;
        else if (format_video_sync == VSYNC_VFR) {
            if (vdelta <= -0.6) {
                nb_frames = 0;
            } else if (vdelta > 0.6)
                ost->sync_opts = lrintf(sync_ipts);
        } /*else if (fabs(vdelta) > 1.1)
            nb_frames = lrintf(vdelta);
fprintf(stderr, "vdelta:%f = sync_ipts:%f, ost->sync_opts:%"PRId64", duration:%f nb_frames:%d\n", vdelta, sync_ipts, ost->sync_opts, duration, nb_frames);
	//av_log(NULL, AV_LOG_VERBOSE, "vdelta [ffmpeg]\n");
        if (nb_frames == 0) {
            ++nb_frames_drop;
            av_log(NULL, AV_LOG_VERBOSE, "*** drop! [ffmpeg]\n");
        } else if (nb_frames > 1) {
            nb_frames_dup += nb_frames - 1;
            av_log(NULL, AV_LOG_VERBOSE, "*** %d dup! [ffmpeg]\n", nb_frames - 1);
        }*/nb_frames = 1;
    } else
        ost->sync_opts = lrintf(sync_ipts);

    nb_frames = FFMIN(nb_frames, ost->max_frames - ost->frame_number);
    if (nb_frames <= 0)
        return;

    do_video_resample(ost, ist, in_picture, &final_picture);

    /* duplicates frame if needed */
    for (i = 0; i < nb_frames; i++) {
        AVPacket pkt;
        av_init_packet(&pkt);
        pkt.stream_index = ost->index;

        if (s->oformat->flags & AVFMT_RAWPICTURE &&
            enc->codec->id == CODEC_ID_RAWVIDEO) {
            /* raw pictures are written as AVPicture structure to
               avoid any copies. We support temporarily the older
               method. */
            enc->coded_frame->interlaced_frame = in_picture->interlaced_frame;
            enc->coded_frame->top_field_first  = in_picture->top_field_first;
            pkt.data   = (uint8_t *)final_picture;
            pkt.size   =  sizeof(AVPicture);
            pkt.pts    = av_rescale_q(ost->sync_opts, enc->time_base, ost->st->time_base);
            pkt.flags |= AV_PKT_FLAG_KEY;

            write_frame(s, &pkt, ost);
        } else {
            AVFrame big_picture;

            big_picture = *final_picture;
            /* better than nothing: use input picture interlaced
               settings */
            big_picture.interlaced_frame = in_picture->interlaced_frame;
            if (ost->st->codec->flags & (CODEC_FLAG_INTERLACED_DCT|CODEC_FLAG_INTERLACED_ME)) {
                if (ost->top_field_first == -1)
                    big_picture.top_field_first = in_picture->top_field_first;
                else
                    big_picture.top_field_first = !!ost->top_field_first;
            }

            /* handles same_quant here. This is not correct because it may
               not be a global option */
            big_picture.quality = quality;
            if (!enc->me_threshold)
                big_picture.pict_type = 0;
//            big_picture.pts = AV_NOPTS_VALUE;
            big_picture.pts = ost->sync_opts;
//            big_picture.pts= av_rescale(ost->sync_opts, AV_TIME_BASE*(int64_t)enc->time_base.num, enc->time_base.den);
// av_log(NULL, AV_LOG_DEBUG, "%"PRId64" -> encoder\n", ost->sync_opts);
            if (ost->forced_kf_index < ost->forced_kf_count &&
                big_picture.pts >= ost->forced_kf_pts[ost->forced_kf_index]) {
                big_picture.pict_type = AV_PICTURE_TYPE_I;
                ost->forced_kf_index++;
            }
            ret = avcodec_encode_video(enc,
                                       bit_buffer, bit_buffer_size,
                                       &big_picture);
            if (ret < 0) {
                av_log(NULL, AV_LOG_FATAL, "Video encoding failed\n");
                exit_program(1);
            }

            if (ret > 0) {
                pkt.data = bit_buffer;
                pkt.size = ret;
                if (enc->coded_frame->pts != AV_NOPTS_VALUE)
                    pkt.pts = av_rescale_q(enc->coded_frame->pts, enc->time_base, ost->st->time_base);
/*av_log(NULL, AV_LOG_DEBUG, "encoder -> %"PRId64"/%"PRId64"\n",
   pkt.pts != AV_NOPTS_VALUE ? av_rescale(pkt.pts, enc->time_base.den, AV_TIME_BASE*(int64_t)enc->time_base.num) : -1,
   pkt.dts != AV_NOPTS_VALUE ? av_rescale(pkt.dts, enc->time_base.den, AV_TIME_BASE*(int64_t)enc->time_base.num) : -1);*/

                if (enc->coded_frame->key_frame)
                    pkt.flags |= AV_PKT_FLAG_KEY;
                write_frame(s, &pkt, ost);
                *frame_size = ret;
                video_size += ret;
                // fprintf(stderr,"\nFrame: %3d size: %5d type: %d",
                //         enc->frame_number-1, ret, enc->pict_type);
                /* if two pass, output log */
                if (ost->logfile && enc->stats_out) {
                    fprintf(ost->logfile, "%s", enc->stats_out);
                }
            }
        }
        ost->sync_opts++;
        /*
         * For video, number of frames in == number of packets out.
         * But there may be reordering, so we can't throw away frames on encoder
         * flush, we need to limit them here, before they go into encoder.
         */
        ost->frame_number++;
    }
}