imx-drm: Color issues scanning out YUV420 frames through the overlay plane.

imx-drm: Color issues scanning out YUV420 frames through the overlay plane.

[Javier Martin]

Hi,
I am using mainline kernel 4.1 and I was writing a small application 
that uses double buffering to read YUV420 frames from a file at 30fps 
and displays them using the overlay plane in the imx-drm driver.

The first issue I noticed is that the image was green so I had to apply 
the following patches to make the U and V components be scanned out 
properly:

http://lists.freedesktop.org/archives/dri-devel/2014-October/071052.html
http://lists.freedesktop.org/archives/dri-devel/2014-October/071025.html
http://lists.freedesktop.org/archives/dri-devel/2014-October/071048.html

The thing is that, even after applying the 3 patches above, colors are a 
bit strange. They seem about right but there are some artifacts, like a 
saturation effect that spoils the image. You can see some snapshots here 
to see what I am talking about:
https://imageshack.com/i/f0nAM5Xbj
https://imageshack.com/i/hl7bZMNjj
https://imageshack.com/i/eyRjURxRj

And the original video is the first one in this page:
http://media.xiph.org/video/derf/

On the other hand, colors in the primary plane using the fbdev interface 
and RGB look correct.

Has anyone seen something similar or is YUV420 working fine for you?

Regards,
Javier.

Re: imx-drm: Color issues scanning out YUV420 frames through the overlay plane.

[Javier Martin]

Sorry for sending this to the wrong list.

On 07/08/15 09:25, Javier Martin wrote:
> Hi,
> I am using mainline kernel 4.1 and I was writing a small application
> that uses double buffering to read YUV420 frames from a file at 30fps
> and displays them using the overlay plane in the imx-drm driver.
>
> The first issue I noticed is that the image was green so I had to apply
> the following patches to make the U and V components be scanned out
> properly:
>
> http://lists.freedesktop.org/archives/dri-devel/2014-October/071052.html
> http://lists.freedesktop.org/archives/dri-devel/2014-October/071025.html
> http://lists.freedesktop.org/archives/dri-devel/2014-October/071048.html
>
> The thing is that, even after applying the 3 patches above, colors are a
> bit strange. They seem about right but there are some artifacts, like a
> saturation effect that spoils the image. You can see some snapshots here
> to see what I am talking about:
> https://imageshack.com/i/f0nAM5Xbj
> https://imageshack.com/i/hl7bZMNjj
> https://imageshack.com/i/eyRjURxRj
>
> And the original video is the first one in this page:
> http://media.xiph.org/video/derf/
>
> On the other hand, colors in the primary plane using the fbdev interface
> and RGB look correct.
>
> Has anyone seen something similar or is YUV420 working fine for you?
>
> Regards,
> Javier.
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