[vlc] Re: YV12 rendering errors

[MagicITX]

On 1/13/06, MagicITX <magicitx at gmail.com> wrote:
>
> I was having trouble with VLC on a VIA EPIA system using the openchrome Xv
> driver.  While working to resolve it with Thomas Hellstrom of the openchrome
> project he reported: "It seems that VLC doesn't format the Xv images as the
> X server tells it to do. In particular, it doesn't adhere to pitches. This
> makes YV12 produce rendering errors on widths that are not multiples of 32,
> but YUY2 is OK for widths that are multiples of 16. (when dmablit is on,
> otherwise the openchrome driver requests that strides and widths are the
> same). This should really be communicated to the VLC developers."
>
> --
>
> Tim
> www.magicitx.com
>

I updated the openchrome driver and via drm driver but vlc had green tint on
the bottom lines of the image.  That is the effect of the above bug.  Thomas
added:

"That's the VLC bug. (3 above). The via driver tells vlc to use 368 for
chroma stride, but it uses 360. Hence there is no chroma data for the last
lines, and if you look closely the rest of the picture is in black and white
with diagonal misrendered colors on it. It works when not using PCI DMA,
because then the via driver tells VLC to use 360, which it does anyway.

A temporary workaround for 720 width is to use YUY2, but the best thing
would be if you communicated this to VLC developers."

I'll take a look at the vlc code and see if I can fix it.

--

Tim
www.magicitx.com
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