FFmpeg - Crop image white space

Question

I'm looking for a way, with FFmpeg, to crop an image removing all white pixels; something like the Photoshop's "crop white spaces".

I tried looking around but I didn't find a solution, here is an example of what I'm looking for:

Given this:

I would be able to obtain this:

How should I get this edit?

Answer 1

1. Use negate to invert the image colors and cropdetect to find crop parameters:

   ffmpeg -loop 1 -i input.png -frames:v 3 -vf "negate,cropdetect=limit=0:round=0" -f null -
   ...
   [Parsed_cropdetect_1 @ 0x5581f7287580] x1:198 x2:1255 y1:472 y2:968 w:1058 h:496 x:198 y:472 pts:3 t:0.120000 crop=1056:496:200:472
   

2. Test with ffplay if desired:

   ffplay -vf crop=1056:496:200:472 input.png
   

3. Then use crop:

   ffmpeg -i input.png -vf crop=1056:496:200:472 output.png
   

See ffmpeg get value from cropdetect for a Bash shell example to extract the cropdetect value for scripted usage.