Fieldmatch

Video Single output Transform

Field matching for inverse telecine.

FFmpeg filter: fieldmatch — the official reference.

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

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

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

$result = $video->apply(new Fieldmatch(…), $other);

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
order	FieldmatchOrder	auto	auto, bff, tff	specify the assumed field order
mode	FieldmatchMode	pc_n	pc, pc_n, pc_u, pc_n_ub, pcn, pcn_ub	set the matching mode or strategy to use
ppsrc	bool	false	—	mark main input as a pre-processed input and activate clean source input stream
field	FieldmatchField	auto	auto, bottom, top	set the field to match from
mchroma	bool	true	—	set whether or not chroma is included during the match comparisons
y0	int	0	≥ 0	define an exclusion band which excludes the lines between y0 and y1 from the field matching decision
y1	int	0	≥ 0	define an exclusion band which excludes the lines between y0 and y1 from the field matching decision
scthresh	float	12	0–100	set scene change detection threshold
combmatch	FieldmatchCombmatching	sc	none, sc, full	set combmatching mode
combdbg	FieldmatchDbglvl	none	none, pcn, pcnub	enable comb debug
cthresh	int	9	-1–255	set the area combing threshold used for combed frame detection
chroma	bool	false	—	set whether or not chroma is considered in the combed frame decision
blockx	int	16	4–512	set the x-axis size of the window used during combed frame detection
blocky	int	16	4–512	set the y-axis size of the window used during combed frame detection
combpel	int	80	≥ 0	set the number of combed pixels inside any of the blocky by blockx size blocks on the frame for the frame to be detected as combed

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