[linux-dvb] Re: V4Lx and colorspace formats...

[Michael Hunold <hunold@convergence.de>]

Hello Guido,

> Did some tests with dvb-kernel+other drivers and using UYVY-Format instead of 
> YUV2 in kvdr.
Ok, ok, you got me. 8-) Although I said that I won't look at the DVB 
driver...

> The results:
>
> linux-dvb: (same with "old" 0.9.4-drivers)
> YUV2 working with glitches, UYVY wrong colors
I've fixed this. You can now use UYVY and the colors will be right. This 
was a driver bug.

Just to make things clear:
VIDEO_PALETTE_YUV422 corrseponds to xv 0x32595559 (YUY2)
VIDEO_PALETTE_UYVY corresponds to xv 0x59565955 (UYVY)

If you change this accordingly in kvdr.cpp and kvdr_xv.cpp everything is 
fine.

But again: please use VIDEO_PALETTE_UYVY, because it's not swapped in 
software!

(Little note: It's YUY2, not YUV2)

> dvb-kernel:
> YUV2 not working, UYVY working fine _without_ the annoying glitches and with 
> much less cpu !!!
YUY2 will never be supported (software swapping).

> bttv:
> YUV2 working, UYVY not working
Which bttv version are you using? IMHO bttv supports both version, but 
it might be in 0.9.x versions (v4l2) only.

> So i'am in the very unfortunate position to choose my poison:
> Not a single combination allows for bttv+dvb both running fine with the same 
> colorspace.
The problem is now, that VIDEO_PALETTE_YUV422 is supported, although 
it's slow. There is no way to get this information from the driver. It 
would be best if VIDEO_PALETTE_YUV422 was removed from the driver 
completely.

So you could test first if the driver supports VIDEO_PALETTE_UYVY and if 
so, use it. Otherwise test and use VIDEO_PALETTE_YUV422.

Btw: you don't check any of the ioctl return values in kvdr, do you?

> As kvdr is intended for dvb only i would skip (Xv)-support for bttv - but it 
> would be fine, if linux-dvb and dvb-kernel would both support UYVY the same 
> way - is this just a temporary discrepancy?
Yes, now they both support VIDEO_PALETTE_UYVY.

CU
Michael.



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