PS will work if there is only one stream as the muxer doesn't set
       correctly dts/length for muxed packets. (so pretty useless ;)
        - added mpeg1/2 video. (how overcomplicated is rfc2250),
       tested with mplayer+live.com (but I'm not sure that my ES parsing
       is ok.)
        - btw, there is a ttl option.