lossless-cut/docs/expressions.md

JavaScript expressions

LosslessCut has support for JavaScript expressions in certain dialogs. This is a base JavaScript environment with core JavaScript functionality available for you to use.

Select segments by expression

You will be given a global variable called segment (type Segment) and you can create an expression that returns true or false based on custom logic. For example to select all segments with a duration of less than 5 seconds use this expression:

segment.duration < 5

Edit segments by expression

LosslessCut has support for normal JavaScript expressions. You will be given a variable segment (type Segment) for each selected segment and can return a new segment with modified properties.

See more examples in-app.

Output name template

You can also use JavaScript expressions when referring to variables inside ${} in output file name templates, e.g. ${FILENAME.toLowerCase()}.

See also Export file name template.