Aeval

Audio Single output Transform

Filter audio signal according to a specified expression.

FFmpeg filter: aeval — 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   = $audio->addFilter(new Aeval(…));
$result = $node->outputs()[0];

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

$result = $audio->apply(new Aeval(…));

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
exprs	string	—	—	set the ’|‘-separated list of channels expressions
channel_layout	string	—	—	set channel layout

FFmpeg also names these options (use the parameter shown above): c → channel_layout.

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