[INFO] Another Tonemapping Discussion. (FFmpeg)

[DevSker]

"Converting primaries to bt709 before tonemapping is incompatible with a tonemap desaturation value of other than 0, it clips pixels to black that have colors outside the bt709 colorspace." I've tested that statement and could reproduce the problem.
Also, is it possible to change the "npl" value? Seems like it's 100, but using higher values can give you better results.

About the black pixels:
Using "zscale=t=linear:npl=100,format=gbrpf32le,zscale=p=bt709,tonemap=tonemap=mobius:desat=1,zscale=t=bt709:m=bt709:r=tv,format=yuv420p"
Instead of something like "zscale=t=linear:npl=100,format=gbrpf32le,tonemap=tonemap=mobius:desat=1,zscale=p=bt709:t=bt709:m=bt709:r=tv,format=yuv420p"
Had this issue:

(https://cdn.discordapp.com/attachments/4...desat1.mp4)

About npl:
As you can see on the samples below, npl=100 is just too bright and can make some details almost disappear. Parameters used: ffmpeg -i HDRSample.webm -vf zscale=t=linear:npl=(>=100),format=gbrpf32le,tonemap=tonemap=mobius:desat=0,zscale=p=bt709:t=bt709:m=bt709:r=tv,format=yuv420p -c:v libx264 -preset veryslow -crf 18 output.mp4

npl=100 -> https://cdn.discordapp.com/attachments/4...desat0.mp4
npl=200 -> https://cdn.discordapp.com/attachments/9...desat0.mp4
npl=500 -> https://cdn.discordapp.com/attachments/4...desat0.mp4
npl=1000 -> https://cdn.discordapp.com/attachments/4...desat0.mp4

Sample -> https://cdn.discordapp.com/attachments/9...ample.webm