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
Join clipA.mp4 and clipB.mp4 with a flash transition Length of the transition in seconds: 0.6
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.
Put a sale badge on @clip1.mp4, give @clip2.mp4 a VHS look, then join them with a flash transition.
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 |
|---|---|---|
D | 0.6 | Length of the transition in seconds. |
In other editors
From each editor’s own help pages, in our words. We haven’t run these ourselves.
Closest built-in: White Flash transition · desktop
- Import your video and place it on the timeline.
- Trim the clips, then open the Transitions tab and search for White Flash.
- Place the transition between the clips.
- Click the transition and move the slider to set its duration.
Page only names White Flash under overlay-style transitions (light leaks, lens flares) and never describes its look.
Source: The 8 Best Film Transitions to Make Your Videos Look Seamless And Engaging (CapCut), checked October 22, 2026.
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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Join clipA.mp4 and clipB.mp4 with a 0.6 second flash transition: A fades up to pure white, then B fades in from white (ffmpeg xfade fadewhite). Crossfade the audio over the same 0.6 seconds. Match B's size and frame rate to A. Use ffmpeg and save it as output.mp4.Run it without Claude
This is the exact command we tested. Save it as flash-transition.sh and run:
sh flash-transition.sh clipA.mp4 clipB.mp4 output.mp4Show the command
#!/bin/sh
# Flash transition: the picture burns out to white between the two clips, over 0.6s. The sound crossfades underneath.
# Usage: sh flash-transition.sh clipA.mp4 clipB.mp4 output.mp4 (both clips need an audio track)
set -e
A="$1"; B="$2"; OUT="$3"
D=0.6 # transition length in seconds
LEN=$(ffprobe -v error -show_entries format=duration -of csv=p=0 "$A")
OFFSET=$(echo "$LEN - $D" | bc)
SIZE=$(ffprobe -v error -select_streams v:0 -show_entries stream=width,height -of csv=s=x:p=0 "$A")
FPS=$(ffprobe -v error -select_streams v:0 -show_entries stream=r_frame_rate -of csv=p=0 "$A")
W=${SIZE%x*}; H=${SIZE#*x}
# xfade needs both clips at the same size and frame rate, so B is fitted to A first
ffmpeg -y -i "$A" -i "$B" -filter_complex "\
[0:v]fps=$FPS,format=yuv420p,setsar=1[a];\
[1:v]scale=$W:$H:force_original_aspect_ratio=increase,crop=$W:$H,fps=$FPS,format=yuv420p,setsar=1[b];\
[a][b]xfade=transition=fadewhite:duration=$D:offset=$OFFSET[v];\
[0:a][1:a]acrossfade=d=$D[au]" \
-map "[v]" -map "[au]" -c:v libx264 -crf 18 -pix_fmt yuv420p -c:a aac "$OUT"
