Live is not a video editor and does not pretend to be. What it does is show you a picture while you work on the audio, keep them locked together, and export the pair — which is all you need to score to picture.
Getting the video in
Drag a video file onto a track in the Arrangement View. The audio from the file lands as a normal audio clip, and a Video Window opens showing the picture. Scrub the arrangement and the picture follows.
The video clip behaves like an audio clip — move it, trim it, and the picture moves with it.
Working to picture
- Locators are your friend. Drop one at every hit point you need to catch. Name them. Now you can jump between them and see the frame you are writing to.
- Set the ruler to show time rather than bars while you are placing hits, then switch back to bars to write the music.
- The tempo is yours to choose — pick one where the hit points land near bar lines and the writing gets much easier. This is what tempo mapping is for.
Trimming tricks
The video's start is set by the clip's start marker, so trimming the front of the audio clip trims the front of the picture. To hold a frame or offset the picture without moving the audio, use the clip's start offset rather than moving the clip.
Getting it back out
Export with Create Video enabled and Live muxes your finished audio back onto the original picture. The video is not re-encoded, so nothing is lost — it is your audio on their frames.
Check the frame rate before you deliver. Most sync problems in a video export are a frame rate mismatch rather than anything you did in the timeline.
Worth knowing
The same workflow covers more than film. Scoring a game trailer, building a DJ set to visuals, editing a podcast against a recorded video call — all the same three moves: import, locate the hit points, export with the picture.