Hello Leonid,.
is there way to "catch" vertical frame (field) synchronization
using BT8x8 cards and bttv driver ?
You have to distinguish between the synchronisation of your image source
(ie. the bt8x8 card) and the synchronisation of your output (ie. your
graphics adapter).
In overlay mode (ie. when the bt8x8 is writing directly to your
framebuffer) there is nearly no way that you can synchronize these two,
especially if you're using a TFT. While the video is incoming with 25
frames (or 50 fields) per seconds, the TFT is usally displaying it's
picture with 60 frames per seconds.
In grabbing mode (ie. when the bt8x8 writes the picture to some
offscreen memory), the synchronisation of your incoming picture is not
important.
What you really need is a way to synchronise the output, ie. a way to
tell your output device: "wait for the next vertical sync, then flip to
the next frame, so I don't get any tearing effects".
I don't know if X finally has something (ie. a "X vsync extension") like
this, otherwise you need to use some other toolkit like DirectFB
(http:/www.directfb.org) that lets you sync your output to the vsync.
Regards,
Leo.
CU
Michael.
