[FFmpeg-devel] [PATCH] fate/pixfmt: disable dithering in the scale filter

[James Almer]

On 11/8/2024 5:15 AM, Martin Storsjö wrote:
> On Thu, 7 Nov 2024, James Almer wrote:
> 
>> Should fix fate failures across different systems.
>>
>> Signed-off-by: James Almer <jamrial at gmail.com>
>> ---
>> This only hides the bug in the dither path for unscaled planar yuv 
>> 8bit to
>> hbd and vice-versa.
>> Someone more familiar with the code should check what exactly is going 
>> on.
> 
> LGTM, thanks! Good job in hunting this one down - it seems odd as the 
> exact output value seems stable on each machine (and valgrind doesn't 
> find any nondeterminism), but the output is different on most machines.

The only tests that fail are those using the DITHER_COPY method in 
planarCopyWrapper() when dither is used, and the only difference 
compared to the no dither path is accessing the "dithers" static const 
array defined in the same file.
Maybe compilers are doing something weird when aligning it, or accessing it?

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