(s->cur_timestamp * 90000LL * FRAME_RATE_BASE) / st->codec.frame_rate;
av_rescale((int64_t)s->cur_timestamp * st->codec.frame_rate_base, 90000, st->codec.frame_rate);
static void rtp_send_mpegvideo(AVFormatContext *s1,                               uint8_t *buf1, int size){    RTPContext *s = s1->priv_data;    AVStream *st = s1->streams[0];    int len, h, max_packet_size;    uint8_t *q;    max_packet_size = s->max_payload_size;    while (size > 0) {        /* XXX: more correct headers */        h = 0;        if (st->codec.sub_id == 2)            h |= 1 << 26; /* mpeg 2 indicator */        q = s->buf;        *q++ = h >> 24;        *q++ = h >> 16;        *q++ = h >> 8;        *q++ = h;        if (st->codec.sub_id == 2) {            h = 0;            *q++ = h >> 24;            *q++ = h >> 16;            *q++ = h >> 8;            *q++ = h;        }                len = max_packet_size - (q - s->buf);        if (len > size)            len = size;        memcpy(q, buf1, len);        q += len;        /* 90 KHz time stamp */        /* XXX: overflow */        s->timestamp = s->base_timestamp +             (s->cur_timestamp * 90000LL * FRAME_RATE_BASE) / st->codec.frame_rate;        rtp_send_data(s1, s->buf, q - s->buf);        buf1 += len;        size -= len;    }    s->cur_timestamp++;}