Elbg

Video Single output Transform

Apply posterize effect, using the ELBG algorithm.

FFmpeg filter: elbg — the official reference.

Add it to a graph. The explicit form works for every filter — bind it to its input and read the result from outputs():

$node   = $video->addFilter(new Elbg(…));
$result = $node->outputs()[0];

Shorthand. Single-output filters can skip the node — apply() returns the result stream directly:

$result = $video->apply(new Elbg(…));

When to use it

TODO — when this filter shines: what it’s the right tool for, what to reach for instead when it isn’t, and how it composes with neighbouring filters.

How to use it

TODO — prose: how the filter actually works and what its key parameters mean (the explanation FFmpeg’s terse option help omits).

Examples

TODO — runnable PHP, with the equivalent ffmpeg CLI alongside.

Gotchas

TODO

See also

TODO

Parameters

Parameter	Type	Default	Range / values	Description
codebook_length	int	256	≥ 1	set codebook length
nb_steps	int	1	≥ 1	set max number of steps used to compute the mapping
seed	int	-1	≥ -1	set the random seed
pal8	bool	false	—	set the pal8 output
use_alpha	bool	false	—	use alpha channel for mapping

FFmpeg also names these options (use the parameter shown above): l → codebook_length, n → nb_steps, s → seed.

---

Maps to FFmpeg’s elbg filter. Verified against ffmpeg n7.1.1.