| Video || Audio || RGB || YUV || YUV422 || multiple instances || processing type || frames needed |
| yes || no || yes || yes || no || yes || PRE/POST || 1 |
Detect black regions on top, bottom, left and right of an image. It is suggested that the filter is run for around 100 frames. It will print its detected parameters every frame. If you don't notice any change in the printout for a while, the filter probably won't find any other values. The filter converges, meaning it will learn.
Default values are shown in [green]
in square brackets.
- range Apply filter to [start-end]/step frames (0-oo - 0-oo/0-oo) [0-oo/1]
- limit The sum of a line must be below this limit to be considered as black (0-255) 
- post Run as a POST filter
- Calc -Y instead of the default -j