Blackdetect

Video Single output Transform

Detect video intervals that are (almost) black.

FFmpeg filter: blackdetect — 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 Blackdetect(…));
$result = $node->outputs()[0];

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

$result = $video->apply(new Blackdetect(…));

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
black_min_duration	float	2	≥ 0	set minimum detected black duration in seconds
picture_black_ratio_th	float	0.98	0–1	set the picture black ratio threshold
pixel_black_th	float	0.1	0–1	set the pixel black threshold

FFmpeg also names these options (use the parameter shown above): d → black_min_duration, pic_th → picture_black_ratio_th, pix_th → pixel_black_th.

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