static void compute_pkt_fields2(AVStream *st, AVPacket *pkt){
static int compute_pkt_fields2(AVStream *st, AVPacket *pkt){
static void compute_pkt_fields2(AVStream *st, AVPacket *pkt){    int b_frames = FFMAX(st->codec.has_b_frames, st->codec.max_b_frames);    int num, den, frame_size;//    av_log(NULL, AV_LOG_DEBUG, "av_write_frame: pts:%lld dts:%lld cur_dts:%lld b:%d size:%d st:%d\n", pkt->pts, pkt->dts, st->cur_dts, b_frames, pkt->size, pkt->stream_index);    /*    if(pkt->pts == AV_NOPTS_VALUE && pkt->dts == AV_NOPTS_VALUE)        return -1;*/                if(pkt->pts != AV_NOPTS_VALUE)        pkt->pts = av_rescale(pkt->pts, st->time_base.den, AV_TIME_BASE * (int64_t)st->time_base.num);    if(pkt->dts != AV_NOPTS_VALUE)        pkt->dts = av_rescale(pkt->dts, st->time_base.den, AV_TIME_BASE * (int64_t)st->time_base.num);    /* duration field */    pkt->duration = av_rescale(pkt->duration, st->time_base.den, AV_TIME_BASE * (int64_t)st->time_base.num);    if (pkt->duration == 0) {        compute_frame_duration(&num, &den, st, NULL, pkt);        if (den && num) {            pkt->duration = av_rescale(1, num * (int64_t)st->time_base.den, den * (int64_t)st->time_base.num);        }    }    //XXX/FIXME this is a temporary hack until all encoders output pts    if((pkt->pts == 0 || pkt->pts == AV_NOPTS_VALUE) && pkt->dts == AV_NOPTS_VALUE && !b_frames){        pkt->dts=//        pkt->pts= st->cur_dts;        pkt->pts= st->pts.val;    }    //calculate dts from pts        if(pkt->pts != AV_NOPTS_VALUE && pkt->dts == AV_NOPTS_VALUE){        if(b_frames){            if(st->last_IP_pts == AV_NOPTS_VALUE){                st->last_IP_pts= -pkt->duration;            }            if(st->last_IP_pts < pkt->pts){                pkt->dts= st->last_IP_pts;                st->last_IP_pts= pkt->pts;            }else                pkt->dts= pkt->pts;        }else            pkt->dts= pkt->pts;    }    //    av_log(NULL, AV_LOG_DEBUG, "av_write_frame: pts2:%lld dts2:%lld\n", pkt->pts, pkt->dts);    st->cur_dts= pkt->dts;    st->pts.val= pkt->dts;    /* update pts */    switch (st->codec.codec_type) {    case CODEC_TYPE_AUDIO:        frame_size = get_audio_frame_size(&st->codec, pkt->size);        /* HACK/FIXME, we skip the initial 0-size packets as they are most likely equal to the encoder delay,           but it would be better if we had the real timestamps from the encoder */        if (frame_size >= 0 && (pkt->size || st->pts.num!=st->pts.den>>1 || st->pts.val)) {            av_frac_add(&st->pts, (int64_t)st->time_base.den * frame_size);        }        break;    case CODEC_TYPE_VIDEO:        av_frac_add(&st->pts, (int64_t)st->time_base.den * st->codec.frame_rate_base);        break;    default:        break;    }}