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

[Christian König]

Hi guys,

Nayan have you taken into account that the pixel center is at 0.5 and 
not 0.0?

Regards,
Christian.

Am 26.06.2016 um 22:30 schrieb 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.
>
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