Cropdetect

Video Single output Transform

Auto-detect crop size.

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

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

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

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
limit	float	0.094117647058824	0–65535	Threshold below which the pixel is considered black
round	int	16	≥ 0	Value by which the width/height should be divisible
reset_count	int	0	≥ 0	Recalculate the crop area after this many frames
skip	int	2	≥ 0	Number of initial frames to skip
max_outliers	int	0	≥ 0	Threshold count of outliers
mode	CropdetectMode	black	black, mvedges	set mode
high	float	0.098039215686275	0–1	Set high threshold for edge detection
low	float	0.058823529411765	0–1	Set low threshold for edge detection
mv_threshold	int	8	0–100	motion vector threshold when estimating video window size

FFmpeg also names these options (use the parameter shown above): reset → reset_count.

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