Timeline edits

Trim, splice, freeze, reverse, and speed changes on the timeline.

Several timeline steps in one project? Use videoPipeline() (advanced) instead of chaining createVideo calls.

Single operation: use the createVideo keys below (one per call).

#trim

What it does: Copies [startTime, endTime] into a new file with stream copy (-c copy) — fast, no re-encode, but cuts must land on keyframes for frame-accuracy.

1await painter.createVideo({2  source: './livestream.mp4',3  trim: {4    startTime: 120,5    endTime: 180,6    outputPath: './highlight-2min.mp4',7  },8});

#replaceSegment (splice)

What it does: Splices replacement footage into [targetStartTime, targetEndTime] of source, keeping head/tail. Same operation as videoPipeline().splice({ … }).

##Modes

Cannot pass both replacementVideo and replacementFrames.

##Options

1await painter.createVideo({2  source: './main.mp4',3  replaceSegment: {4    targetStartTime: 10,5    targetEndTime: 25,6    replacementVideo: './broll.mp4',7    replacementStartTime: 0,8    replacementDuration: 15,9    outputPath: './main-with-broll.mp4',10  },11});

#freezeFrame

What it does: Output = before clip + still image held duration seconds + after clip (concat).

Supports onProgress on final concat.

1await painter.createVideo({2  source: './slides.mp4',3  freezeFrame: {4    time: 8,5    duration: 2.5,6    outputPath: './slides-pause.mp4',7  },8  onProgress: (p) => console.log(p.percent),9});

#reverse

What it does: Plays video backwards (-vf reverse -af areverse). CPU heavy, long runs on big files.

1await painter.createVideo({2  source: './clip.mp4',3  reverse: { outputPath: './clip-rev.mp4' },4});

#changeSpeed

What it does: setpts on video; atempo (possibly chained) on audio. >2× or <0.5× speed uses multiple atempo stages (FFmpeg limit 0.5–2 per stage).

1await painter.createVideo({2  source: './slow.mp4',3  changeSpeed: { speed: 2, outputPath: './fast-review.mp4' },4});

#createTimeLapse

What it does: Same helper as changeSpeed — speed defaults to 10 if omitted.

1await painter.createVideo({2  source: './clouds.mp4',3  createTimeLapse: {4    speed: 30,5    outputPath: './clouds-tl.mp4',6  },7});