YUV overlay won't set the proper mode

Hi all,

I’m writing an application for live display from a 1394 camera. SDL is
so nice I can’t resist using it but I have a problem…

Basically, I receive a YUV flow in the format YUYV YUYV … I should
thus be able to use the YUY2 overlay format (supported by my video
card). This, however, does not seem to work.

If I generate images of the two different formats (YUY2 and UYVY) and I
try the two SDL modes (SDL_YUY2_OVERLAY and SDL_UYVY_OVERLAY), this give
4 possible arrangements. The results are, in a table:

	input image format:




This seems to indicate that either SDL cannot change the overlay mode
properly (and is stuck to YUY2) or that the video card/drivers have
problems. I had complaints from user using different video cards, for
some it works fine, others always get the infamous green/purple image.

I’m using SDL 1.2.3 on a RH7.2 with an ATI RAGE LT PRO (laptop). People
using a matrox G400 reported failure, but a G450 works.

I’m wondering if this is a know issue for SDL or if it’s some
cards/drivers problem.

Thanks for your help,

_ Damien Douxchamps
(?- PhD Student / Research Assistant
//\ Image Processing Group, Telecom Laboratory, UCL, Belgium
V_/_ http://www.tele.ucl.ac.be/MEMBERS/Douxchamps_Damien_e.html