On Samstag 16 September 2006 16:42, Heikki Lindholm wrote:
> la, 2006-09-16 kello 15:25 +0200, Stefan Lucke kirjoitti:
> > On Samstag 16 September 2006 13:38, Heikki Lindholm wrote:
> > > YV12 has different U/V plane order compared to I420. This patch fixes
> > > the YUV() method in the dfb driver accordingly. Without the patch YV12
> > > has wrong colours.
> >
> > So you get wrong colors when YV12 is selected.
>
> Yes.
>
> > Do you get wrong colors too when I420 is selected ?
>
> No. By the spec the U/V ordering is not the same for the I420 and YV12
> color spaces, hence we need to swap pointers somewhere if the source
> data (the video) is always in the same format. When looking at different
> sources of information, there might well be some inconsistency in what
> exactly is the U/V order for the YV12 (or I420.) Anyway, if my patch
> works correctly for other hw (I have g400) then it's probably correct.
>
>From naming that would be correct.
I want to explain my argumentation again.
We get some date from the decoder. Ffmpeg's name for that is YV12.
- If we select X11-Xv with YV12 we get correct colors.
- We get correct colors if we convert YV12 -> YUY2 and allocate an X11-Xv
surface
for format YUY2.
- We get correct colors (same decoder + same YV12 -> YUY2 converter) when
we use a YUY2 surface of directfb.
- Our software OSD converter (RGB -> YV12) produces correct colors too.
By this, it is proven to my opinion that our interpertation of decoded planes
is correct.
First plane Y, second plane U and third plane V.
- We have to specify I420 insteadof YV12 for most DirectFB drivers. So DirectFB
does something bad.
Quoted code from DirectFB is a prove for the fact that they have mixed I420 and
YV12,
as it is not executed in case of I420. With I420 we get correct colors.
If they would swap chroma components in case of DSPF_I420 every thing would be
fine.
It should be an acceptable action for users to toggle between I420 and YV12 to
get
the correct colors.
We could rename the OSD option to some less technical term if thats an issue.
But I definitly vote against touching a swap in this place.
> > In DirectFB is I420 vs YV12 is swapped. I know that video is YV12. But
> > we have to specify I420 in DirectFB. With X11 it is YV12 :-).
> >
> > Look at the code of gfxdriver/radeon/radeon_overlay.c, (line 661):
> >
> > 661 if (surface->format == DSPF_YV12) {
> > 662 __u32 tmp = offsets[1];
> > 663 offsets[1] = offsets[2];
> > 664 offsets[2] = tmp;
> > 665 }
> >
> > They swap U/V in case of YV12 :-( .
> >
> > There is to my optinion no need to swap again.
> >
--
Stefan Lucke
_______________________________________________
Softdevice-devel mailing list
[email protected]
https://lists.berlios.de/mailman/listinfo/softdevice-devel
