[Mesa-dev] Fwd: [PATCH] st/vdpau: use bicubic filter for scaling

[Andy Furniss]

Nayan Deshmukh wrote:
> Hi Andy,
>
> On Sun, Jun 26, 2016 at 12:25 AM, Andy Furniss <adf.lists at gmail.com> wrote:
>
>> Nayan Deshmukh wrote:
>>
>>> Hi Andy,
>>>
>>> Thanks for testing the patches.
>>>
>>> Please send me the videos and ratios with which there is corruption.
>>>
>>
>>
>> https://drive.google.com/file/d/0BxP5-S1t9VEEaHZEM203RFpyNEE/view?usp=sharing
>>
>> This has no aspect encoded and displayed fullscreen on a 1920x1080
>> monitor shows vertical line artifacts over the first 2/3 of the image.
>>
>> When I say lines they are not lines as such just that the distortion
>> on the pendulum shows as it passes over imaginary lines at fixed
>> points on the screen.
>>
>> with mplayer -aspect 4/3 or 16/9 it doesn't.
>>
>
> I tested the videos and found out that the distortion is because of the
> amount
> of calculation done in the fragment shader. I tested the video with
> vl_median_filter
> and it showed no distortion however, with vl_matrix_filter( which requires
> more
> calculations than vl_median_filter) it showed the same distortion. I'll try
> to make it
> more efficient. But it still requires a lot of processing for a single
> pixel as it uses
> 15 neighbouring pixel.

Seems a bit strange, does the processing needed vary greatly with
similar scale amounts? I have a powerful GPU and can force clocks
high, but it makes no difference.

Below is a png showing the artifacts I see on pendulum fullscreen
are these what you see?

If rather than full screen I stretch out the window to scale, there
will be many sizes that don't produce those.

https://drive.google.com/file/d/0BxP5-S1t9VEEd2hwNVp0ZXRSZTA/view?usp=sharing

> Also I don't see any offsets with the videos, may be I am missing something.
> If could tell me more about the offsets, I'll try to debug them.

https://drive.google.com/file/d/0BxP5-S1t9VEEUGZTbndOMzBNZnM/view?usp=sharing

Is a default scale, if you download both pngs and use something to
display them both at the same time and line up the windows one on
top of the other then flip between them you can see although the
windows are lined up the images contained are not.

You can make your own screen/window shots with xwd and display them
with xwud. For me using fluxbox as a desktop it's easy to line up
windows as they snap a bit towards the edge of the screen YMMV.