Blackframe

Video Single output Transform

Detect frames that are (almost) black.

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

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

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

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
amount	int	98	0–100	percentage of the pixels that have to be below the threshold for the frame to be considered black
threshold	int	32	0–255	threshold below which a pixel value is considered black

FFmpeg also names these options (use the parameter shown above): thresh → threshold.

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