Trims a downloaded section with ffmpeg smart cut: frame-accurate on both trim handles, without re-encoding anything beyond the small head span that has to cross into the next keyframe. See planSmartCut for why the tail never needs an encode.
Local source file and trim range relative to that file.
Optional
Optional callback polled while ffmpeg runs; kills child processes when true.
Output path for the trimmed media file.
Trims a downloaded section with ffmpeg smart cut: frame-accurate on both trim handles, without re-encoding anything beyond the small head span that has to cross into the next keyframe. See planSmartCut for why the tail never needs an encode.