Get this effect
Switch to Code in your Claude Desktop App
Install the skill (once)
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Install the Recharm video effects skill: download https://recharm-growth-staging.s3.us-east-2.amazonaws.com/website/downloads/recharm-video-effects.zip and unzip it into ~/.claude/skillsAsk for the effect
Add a smooth slow motion to input.mp4 Playback speed: 0.5 Seconds of output to keep: 6
Several videos, several effects, one ask
Put your clips in the folder, mention them with @, and ask for everything at once. Claude runs one tested script after another on each clip, then joins them.
Add a smooth slow motion to @clip1.mp4, put a sale badge on @clip2.mp4, give @clip3.mp4 a VHS look, then join all three with crossfades.
Settings you can change
Ask Claude to change any of these, or edit them at the top of the command.
| Setting | Default | What it does |
|---|---|---|
SPEED | 0.5 | Playback speed. 0.5 is half speed, so the first 3 seconds of the input fill 6 seconds; 0.25 is quarter speed. |
LENGTH | 6 | Seconds of output to keep. |
FPS | 30 | Output frame rate. The frames the slow-down leaves missing are interpolated from the motion. |
Without the skill
Don’t want to install the skill? Paste this prompt into Claude Code and Claude writes the command itself.
Show the prompt
Turn input.mp4 (540x960, 30fps, 6 seconds) into smooth slow motion at half speed (0.5x): output time t shows input time t / 2 (output 1.0s = input 0.5s, 3.0s = 1.5s, 5.5s = 2.75s), so the first 3 seconds of the input fill a 6-second output. Don't repeat frames: build the in-between frames with motion-compensated frame interpolation (ffmpeg setpts=PTS/0.5 then minterpolate=fps=30:mi_mode=mci:mc_mode=aobmc:me_mode=bidir:vsbmc=1), so every output frame at 30fps differs from the one before. Don't crop, zoom or add anything to the picture, and don't add any text. Keep the input's audio playing at normal speed, cut to 6 seconds. Keep the size and 30fps frame rate, and save it as output.mp4.Run it without Claude
This is the exact command we tested. Save it as smooth-slow-motion.sh and run:
sh smooth-slow-motion.sh input.mp4 output.mp4Show the command
#!/bin/sh
# Smooth slow motion: play the shot at half speed, building the missing in-between frames from the motion.
# Usage: sh smooth-slow-motion.sh input.mp4 output.mp4
# Needs ffmpeg (its minterpolate filter does the frame interpolation).
set -e
IN="$1"; OUT="$2"
SPEED=0.5 # playback speed (0.5 = half speed: the first 3 seconds of the input fill 6 seconds)
LENGTH=6 # seconds of output to keep
FPS=30 # output frame rate; at 0.5x every other frame is a new, interpolated one
ffmpeg -y -i "$IN" -filter_complex \
"[0:v]setpts=PTS/$SPEED,minterpolate=fps=$FPS:mi_mode=mci:mc_mode=aobmc:me_mode=bidir:vsbmc=1[v]" \
-map "[v]" -map 0:a? -t "$LENGTH" -c:v libx264 -crf 18 -pix_fmt yuv420p -c:a aac "$OUT"
