[FFMPEG]MUXER：MPEGTS

代码文件：libavformat/mpegtsenc.c

##1.PAT/PMT插入间隔

1.1.插入间隔实质是根据ts->pat_period*90000.0) ，sdt_packet_period和 force_pat共同决定的;

static void retransmit_si_info(AVFormatContext *s, int force_pat, int64_t dts)
{
    ......
    if (++ts->pat_packet_count == ts->pat_packet_period ||
        (dts != AV_NOPTS_VALUE && ts->last_pat_ts == AV_NOPTS_VALUE) ||
        (dts != AV_NOPTS_VALUE && dts - ts->last_pat_ts >= ts->pat_period*90000.0) ||
        force_pat) {
        ts->pat_packet_count = 0;
        if (dts != AV_NOPTS_VALUE)
            ts->last_pat_ts = FFMAX(dts, ts->last_pat_ts);
        mpegts_write_pat(s);
        for (i = 0; i < ts->nb_services; i++)
            mpegts_write_pmt(s, ts->services[i]);
    }