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 glow to input.mp4 Only brightness above this (0-1) glows: 0.78 Blur sigma in pixels: how far the light spreads: 16
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 glow 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 |
|---|---|---|
THRESHOLD | 0.78 | Only brightness above this (0-1) glows. Lower it for more glow. |
RADIUS | 16 | Blur sigma in pixels: how far the light spreads. |
STRENGTH | 0.7 | How much of the halo is added back onto the picture (0-1). |
START | 0.5 | Second the glow starts fading up. |
RAMP | 1.0 | Seconds it takes to reach full strength. 0 turns it on at once. |
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 glow (bloom) effect to input.mp4 with ffmpeg: convert to RGB, take a copy that keeps only brightness above 0.78 on a 0-1 scale (map 0.78-1.0 to 0-1, everything darker goes black), blur it with a Gaussian blur of sigma 16 pixels, and add it back onto the original frame (additive blend) at 70% strength. The glow is off for the first 0.5 seconds, then fades up linearly to full strength over 1 second and stays on to the end. 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 glow-bloom.sh and run:
sh glow-bloom.sh input.mp4 output.mp4Show the command
#!/bin/sh
# Glow: the brightest parts of the picture spill a soft halo of light around them, fading up from 0.5s.
# Usage: sh glow-bloom.sh input.mp4 output.mp4
# Needs ffmpeg.
set -e
IN="$1"; OUT="$2"
THRESHOLD=0.78 # only brightness above this (0-1) glows
RADIUS=16 # blur sigma in pixels: how far the light spreads
STRENGTH=0.7 # how much of the halo is added back onto the picture (0-1)
START=0.5 # second the glow starts fading up
RAMP=1.0 # seconds it takes to reach full strength
ffmpeg -y -v error -i "$IN" -filter_complex "
[0:v]format=gbrp,split[base][hi];
[hi]colorlevels=rimin=$THRESHOLD:gimin=$THRESHOLD:bimin=$THRESHOLD,gblur=sigma=$RADIUS,fade=t=in:st=$START:d=$RAMP[glow];
[base][glow]blend=all_mode=addition:all_opacity=$STRENGTH,format=yuv420p[v]" \
-map "[v]" -map 0:a? -r 30 -c:v libx264 -crf 18 -c:a copy "$OUT"
