[FFmpeg-devel] [PATCH] lavc/rawdec: Only use AV_PIX_FMT_PAL8 for 1 bpp video

Mats Peterson matsp888 at yahoo.com
Mon Feb 1 04:48:08 CET 2016


On 01/31/2016 11:22 PM, Mats Peterson wrote:

>> also i dont think its just avi. The raw video decoder is potentially
>> used for more than avi.
>> mkv and nut come to mind as potential formats that might use the
>> same codepath
>>
>
> Yes it is used for other file formats as well, but only AVI and
> QuickTime explicitly have a palettized 1 bpp mode (as far as I know), so
> they should use pal8 for 1 bpp, and not monow. Other formats aren't
> affected.
>
> Mats


Your patch that switches to monow when a 1 bpp AVI doesn't contain a 
palette is rather kludgy and redundant to me. And users will undoubtly 
be more surprised when they discover that monow is used for the special 
case of 1 bpp AVI without a palette, rather than using pal8 consistently 
for all 1 bpp AVI files, just like 2 and 4 bpp.

I don't understand what's so important about retaining monow inside 
FFmpeg when it comes to AVI, when it's obviously OK to convert 2 and 4 
bpp to pal8. Once again, if you want a straight passthrough of 1 bpp AVI 
video data, just use "-c:v copy".

Mats



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