[FFmpeg-user] question about displace filter

[Michael Koch]

 > Yes, with geq filter. Remap filter documentation is on FFmpeg wiki.

I can't find an example how to make the Xmap and Ymap files with ffmpeg.
In the wiki the files are made with a C program which is difficult to 
understand.
https://trac.ffmpeg.org/wiki/RemapFilter

This example is from the documentation of the displace filter:

ffmpeg -i INPUT -f lavfi -i nullsrc=s=hd720,lutrgb=128:128:128 -f lavfi 
-i 
nullsrc=s=hd720,geq='r=128+30*sin(2*PI*X/400+T):g=128+30*sin(2*PI*X/400+T):b=128+30*sin(2*PI*X/400+T)' 
-lavfi '[0][1][2]displace' OUTPUT

However for the remap filter we need only one 16-bit value per pixel. 
Not three 8-bit RGB values. How can this be created with ffmpeg?

Michael