[vdr] Trying to understand MPEG-TS (PMT, PES etc)

Hi,

I am digging into DVB streams and TS demuxing, and I was wondering: is the PMT the *only* (reasonable) way to determine which codec a given PES is using, please?

The TS demuxing code that I am reading (*cough* xine's) seems to have the idea that if it receives an audio or video PES with a PID that it hasn't seen before then it can "autodetect" the stream (somehow?!). But if it has to wait for the next PMT anyway to determine which codec to use then I'm not sure that I understand the point.

Can anyone advise, please? My research into MPEG-TS has only revealed the following, with regards to PMTs:

"Each elementary stream is labeled with a stream_type value."

http://en.wikipedia.org/wiki/MPEG_transport_stream#PMT

Thanks, Chris