[Mesa-dev] [PATCH] nir/lower_tex: Fix the channel ordering during conversion of AYUV images

[Vivek Kasireddy]

On Tue, 15 Jan 2019 09:45:52 +0200
Tapani Pälli <tapani.palli at intel.com> wrote:

> On 1/15/19 4:34 AM, Lionel Landwerlin wrote:
> > When writing this I used this page to figure the bytes' ordering : 
> > https://docs.microsoft.com/en-us/windows/desktop/medfound/recommended-8-bit-yuv-formats-for-video-rendering#ayuv 
> > 
> > Of course endianess confuses everything :(
> > 
> > sunxi seems to support AYUV & VUYA : 
> > https://github.com/allwinner-zh/linux-3.4-sunxi/blob/master/include/video/sunxi_display2.h#L40 
> > 
> > 
> > Finally this patch (and its gstreamer comments) confuses me even
> > more : https://patchwork.freedesktop.org/patch/255529/
> > 
> > I really don't know what's right or wrong here...  
> 
> IMO order 1230 seems wrong to me. Vivek, was the order chosen just 
> because vivid driver outputs that or is it based on anything else,
> like some specification or other information?
Hi Tapani,
I chose the order just by looking at the Vivid driver output. YUYV and
VYUY buffers generated by the Vivid driver were displayed correctly on
Weston and I believed that YUV4 buffers (which I assumed were AYUV)
should have displayed correctly as well. 

-Vivek

> 
> 
> > -
> > Lionel
> > 
> > On 15/01/2019 00:49, Vivek Kasireddy wrote:  
> >> From: "Kasireddy, Vivek" <vivek.kasireddy at intel.com>
> >>
> >> The channel ordering should be 1230 instead of 2103.
> >>
> >> While displaying the packed YUV buffers generated by the Vivid
> >> (Virtual Video) driver on Weston, it was observed that AYUV images
> >> were not displayed correctly. Changing the ordering to 1230 makes
> >> AYUV buffers display as expected.
> >>
> >> CC: Lionel Landwerlin <lionel.g.landwerlin at intel.com>
> >> CC: Tapani Palli <tapani.palli at intel.com>
> >> Signed-off-by: Vivek Kasireddy <vivek.kasireddy at intel.com>
> >> ---
> >>   src/compiler/nir/nir_lower_tex.c | 6 +++---
> >>   1 file changed, 3 insertions(+), 3 deletions(-)
> >>
> >> diff --git a/src/compiler/nir/nir_lower_tex.c 
> >> b/src/compiler/nir/nir_lower_tex.c
> >> index a618b86b34c..7058c54f17c 100644
> >> --- a/src/compiler/nir/nir_lower_tex.c
> >> +++ b/src/compiler/nir/nir_lower_tex.c
> >> @@ -434,10 +434,10 @@ lower_ayuv_external(nir_builder *b, 
> >> nir_tex_instr *tex)
> >>     nir_ssa_def *ayuv = sample_plane(b, tex, 0);
> >>     convert_yuv_to_rgb(b, tex,
> >> -                     nir_channel(b, ayuv, 2),
> >>                        nir_channel(b, ayuv, 1),
> >> -                     nir_channel(b, ayuv, 0),
> >> -                     nir_channel(b, ayuv, 3));
> >> +                     nir_channel(b, ayuv, 2),
> >> +                     nir_channel(b, ayuv, 3),
> >> +                     nir_channel(b, ayuv, 0));
> >>   }
> >>   /*  
> > 
> >