Timeline operations

Read /invideo first.

An edit is a list of operations, applied all or none. Look up each op's fields before its first use (timeline_catalog), and check a big edit with dry_run: true before it lands.

Frame math

• Fields ending in _f are frames at the timeline's own rate; _seconds fields are seconds. Frames = seconds × fps: half a second is 15 frames at 30 fps, 12 at 24.
• Read the rate from the timeline; never assume it.
• Ranges include their start and exclude their end: a clip from 0 to 90 ends on frame 89.
• Reads give times as {value, rate}, which is value / rate seconds.

Tracks and layering

• Higher video tracks draw over lower ones. Build up: footage, then the grade on an adjustment clip over everything below it (add_adjustment), then type and overlays on top.
• A video's sound is its own audio clip, linked to the picture. They move, trim and delete together.
• Give each track one job and name it (set_name): dialogue, music, effects; footage, b-roll, titles. Lock what you aren't touching (set_track_locked).