[FFmpeg-user] Apparently the ffmpeg software scaler "sucks"

Andy Furniss adf.lists at gmail.com
Wed May 18 12:49:36 CEST 2016

Peter Rabbitson wrote:
> On 05/18/2016 06:45 AM, Reuben Martin wrote:
>> curl -s http://www.4p8.com/eric.brasseur/gamma-1.0-or-2.2.png | \
>> ffmpeg -f image2pipe -i - \ -vf
>> 'eq=gamma=0.454545,scale=w=iw/2:h=ih/2,eq=gamma=2.2' \ -vframes 1
>> -c:v bmp -f image2pipe - | ffplay -i -

Messes up a ramp though quantisation wise - maybe not enough bits used
to work with linear light. Didn't try flags.

> This is also suggested in the article from which I got the image. My
>  question was more: shouldn't ffmpeg (as a mid-to-high-end authoring
>  tool) apply this by default? Or at least have some sort of
> easily-accessible -sws-flag or somesuch?

Maybe tricky - I don't know, but that example seems to be for srgb and
video has slightly different curves/ expected display gamma.

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