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 light trails to input.mp4 Brightness (0-1) where a highlight starts to leave a trail: 0.86 Brightness where the trail is at full strength: 0.90
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 light trails 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 |
|---|---|---|
LOW | 0.86 | Brightness (0-1) where a highlight starts to leave a trail. Lower it for more trails. |
HIGH | 0.90 | Brightness where the trail is at full strength. |
DECAY | 0.975 | Share of a trail that survives each frame. Closer to 1 gives longer streaks. |
GLOW | 2.5 | Blur sigma in pixels that softens the streaks. |
DIM | 0.75 | The picture's brightness under the trails, so they stand out. 1 turns dimming off. |
START | 1.0 | Second the trails start. |
Without the skill
Don’t want to install the skill? Paste this prompt into Claude Code and Claude writes the command itself.
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Add a light trails (long-exposure) effect to input.mp4 with ffmpeg, starting at 1.0 seconds; the first second stays untouched. Convert to RGB and split the video into two copies. Copy 1, the base: from 1.0 seconds on, scale every channel down to 75% of its value (output max 0.75 on a 0-1 scale). Copy 2, the trails: per channel, map input levels 0.86-0.90 to 0-1 so only the brightest highlights survive and everything darker turns black; keep it black before 1.0 seconds (fade it in over 0.04 seconds), then run ffmpeg's lagfun filter with decay 0.975 so each highlight leaves a fading trail as it moves, and soften it with a Gaussian blur of sigma 2.5 pixels. Add copy 2 onto copy 1 with an additive blend. Keep the size, the 30fps frame rate, the 6-second length and the audio, encode H.264 yuv420p, and save it as output.mp4.Run it without Claude
This is the exact command we tested. Save it as light-trails.sh and run:
sh light-trails.sh input.mp4 output.mp4Show the command
#!/bin/sh
# Light trails: from 1s the shot dims and its brightest highlights drag long glowing streaks behind them.
# Usage: sh light-trails.sh input.mp4 output.mp4
# Needs ffmpeg.
set -e
IN="$1"; OUT="$2"
LOW=0.86 # brightness (0-1) where a highlight starts to leave a trail
HIGH=0.90 # brightness where the trail is at full strength
DECAY=0.975 # share of a trail that survives each frame (closer to 1 = longer streaks)
GLOW=2.5 # blur sigma in pixels that softens the streaks
DIM=0.75 # the picture's brightness under the trails, so they stand out (1 = no dimming)
START=1.0 # second the trails start
ffmpeg -y -v error -i "$IN" -filter_complex "
[0:v]format=gbrp,split[base][hi];
[base]colorlevels=romax=$DIM:gomax=$DIM:bomax=$DIM:enable='gte(t,$START)'[dimmed];
[hi]colorlevels=rimin=$LOW:gimin=$LOW:bimin=$LOW:rimax=$HIGH:gimax=$HIGH:bimax=$HIGH,
fade=t=in:st=$START:d=0.04,lagfun=decay=$DECAY,gblur=sigma=$GLOW[trails];
[dimmed][trails]blend=all_mode=addition,format=yuv420p[v]" \
-map "[v]" -map 0:a? -r 30 -c:v libx264 -crf 18 -c:a copy "$OUT"
