Video data protocol

Hi,

I have a question videoconference connections.

In case of regular voice connections I set the B protocols: B1 - 1, B2 - 1,
B3 - 0, convert voice data to a-Law (or u-Law) format, reverse bit order and
just put these data to data_req frame (each sides use the same data format).

And how it works with video?
I think I shuld set B protocols the same (1, 1, 0) and convert video data
using some h.26x codec.
Is it right?

In case of video there are several formats H.263 CIF, H.263 QCIF, H.261 etc.
So where the information about video format is placed in data receveid/sent
to capi?
In what way voice and video data are sent together to capi?

In other words, What is the video (and audio) data protocol for ISDN?

Thanks for any response
Krzysztof Sniezynski