Extract frames

The frame preset creates JPEGs and returns only files matching the generated output pattern.

const files = await video.fnExtractFrameToJPG('/media/frames', {
  start_time: '00:00:10',
  duration_time: 30,
  every_n_seconds: 5,
  number: 6,
  size: '640x?',
  quality: 2,
  file_name: 'preview_%s',
});

Sampling modes

Choose exactly one:

• every_n_frames: capture every N decoded frames
• every_n_seconds: capture at a time interval
• every_n_percentage: divide the source by a percentage interval

Combining modes rejects with error code 107 instead of creating an ambiguous filter.

Size expressions

Expression	Result
640x360	Exact dimensions
640x?	Fixed width, calculated height
?x360	Calculated width, fixed height
50%	Half the source dimensions

Odd dimensions are rounded down to an even number for codec compatibility.

Filename replacements

• %t: current timestamp
• %s: requested size
• %x: requested width expression
• %y: requested height expression

The frame sequence suffix is added automatically.