❉Recipe
Speed Ramp
ffmpeg filtergraphRetime a clip with setpts so a short i2v clip stretches to fill the voiceover beat (slow-mo) without re-rolling — the per-segment retime used in the master bake.
5 units use it
What it is
## What it is
A presentation-timestamp retime. `setpts=f*PTS` multiplies every frame's timestamp by `f`, so `f>1` slows the clip down (stretch) and `f<1` speeds it up. The choose-path bake uses it to stretch a fixed 3.9s i2v clip to cover a longer voiceover line: `f = (vo + 1.0) / 3.9`, applied only when the needed time exceeds the base clip length.
## When to use it
- A scene clip is shorter than the VO/beat it must cover — slow it instead of re-generating.
- A hold/anticipation beat where a gentle slow-mo adds weight.
## Knobs
- `f` = the PTS multiplier. >1 = slower, <1 = faster.
- Video-only retime (`setpts`); audio would need a matching `atempo` if present (the bake strips audio with `-an` and remixes later).
How to use it standalone
# Verbatim retime from scripts/tmp-bake-*.sh (plain-segment slow-mo branch): # t = vo + 1.0; if t > BASE(3.9): f = t / BASE ffmpeg -y -t 3.9 -i scene.mp4 -vf "$VF,setpts=$f*PTS" -an -c:v libx264 -preset veryfast -crf 20 -r 24 scene_slow.mp4 # VF = scale=1080:1920:force_original_aspect_ratio=increase,crop=1080:1920,fps=24,setsar=1,format=yuv420p
| Param | Value |
|---|---|
| fps | 24 |
| f_formula | (vo + 1.0) / 3.9 |
| base_clip_sec | 3.9 |
Units that use this recipe
5 unitsEvery finished unit with Speed Ramp in its recipe. Open one to see the full ingredient list, or remix straight from a tile.
