[FFmpeg-user] lagfun misunderstanding?

[Michael Koch]

Am 29.03.2020 um 18:09 schrieb Zedsquared:
>> It's a decimal input which is then treated as a binary bitmask. So dec
>> 10 becomes bin 1010 i.e. filter the 1st and 3rd planes.
>>
>> Gyan
> Ah! that would explain a lot!
>
> I can confirm I'm still confused, however..
>
> My understanding is that RGB24 has three planes, red then green then blue.
>  From your example it seems the masks act big endian so bit 0x08 represents
> the first plane and bit 0x02 the third?
>
> Using planes=10 ( should be Red  and Blue) gives a trail effect on the blue,
> there is no strong red in that source:
> see http://www.robinbussell.co.uk/mov/greenlagtest11.mp4
>
> However using planes=4 (should be G plane by my reasoning) seems to have no
> effect:
>
> http://www.robinbussell.co.uk/mov/greenlagtest12.mp4
>
>
> Just for completeness, here is
>
> planes= 2 :http://www.robinbussell.co.uk/mov/greenlagtest13.mp4 .. blue
> trails evident
>
> In the above examples I also turned up the green before lagfun so full line
> for last example is:
>
>   ffmpeg -i IMG_1685.MOV -q:v 0 -vcodec h264 -acodec aac -strict -2 -filter:v
> format=pix_fmts=rgb24,colorlevels=romax=0.6:bomax=0.6,lagfun=decay=0.999:planes=2
> greenlagtest13.mp4

Try this workaround:

ffmpeg -i IMG_1685.MOV -filter_complex 
"format=rgb24,extractplanes=r+g+b[r][g][b];[g]lagfun=decay=0.999[gg];[gg][b][r]mergeplanes=0x001020:gbrp" 
-t 5 -y greenlagtest.mp4

Michael