---
title: "How to add a blinds transition with Claude (tested prompt and ffmpeg command)"
description: "Ten horizontal slats of clip B close over clip A one after another, starting at the bottom of the frame and climbing to the top in one second. Install one skill and ask Claude Code, or run the ffmpeg command we tested yourself."
url: https://www.recharm.com/effects/blinds-transition
---

# How to add a blinds transition with Claude

Ten horizontal slats of clip B close over clip A one after another, starting at the bottom of the frame and climbing to the top in one second.

Made by the command on this page, from our own test clips.

## Get this effect

1. ### Switch to Code in your [Claude Desktop App](https://claude.com/download)

2. ### Install the skill (once)

   ```
   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/skills
   ```

3. ### Ask for the effect

   ```
   Join clipA.mp4 and clipB.mp4 with a blinds transition
   Length of the transition in seconds: 1.0
   ```

## 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 blinds 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`     | `1.0`   | Length of the transition in seconds. |

## Without the skill

Don’t want to install the skill? Paste this prompt into Claude Code and Claude writes the command itself.

```
Join clipA.mp4 and clipB.mp4 with a 1.0 second venetian blinds transition: cut the frame into 10 equal horizontal slats that fill with B one after another, bottom slat first and top slat last, each slat filling from its top edge down (ffmpeg xfade transition=vuslice, duration=1, offset = A's length minus 1). Crossfade the audio over the same 1.0 second. Match B's size and frame rate to A. Use ffmpeg, keep the audio and save it as output.mp4 (H.264, yuv420p).
```

## Run it without Claude

This is the exact command we tested. Save it as `blinds-transition.sh` and run:

```
sh blinds-transition.sh clipA.mp4 clipB.mp4 output.mp4
```

```
#!/bin/sh
# Blinds transition: clip B closes over clip A in ten horizontal slats, bottom slat first, over 1s. The sound crossfades underneath.
# Usage: sh blinds-transition.sh clipA.mp4 clipB.mp4 output.mp4  (both clips need an audio track)
set -e
A="$1"; B="$2"; OUT="$3"
D=1.0   # 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=${SIZE#*x}
# xfade needs both clips at the same size and frame rate, so B is fitted to A first.
# vuslice cuts the frame into 10 horizontal slats that fill with B one after another, bottom to top.
ffmpeg -y -i "$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=$FPS,format=yuv420p,setsar=1[b];\
[a][b]xfade=transition=vuslice:duration=$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"
```

## More transitions

- [Barn door transition **Barn door transition**](https://www.recharm.com/effects/barn-door)
- [Block dissolve **Block dissolve**](https://www.recharm.com/effects/block-dissolve)
- [Blur transition **Blur transition**](https://www.recharm.com/effects/blur-transition)
- [Bounce transition **Bounce transition**](https://www.recharm.com/effects/bounce-transition)
- [Brush stroke transition **Brush stroke transition**](https://www.recharm.com/effects/brush-stroke-transition)

## Find 3x _winning ads_

Recharm cuts your ad footage into tagged, searchable clips: hooks, testimonials, product shots. Find the shots that win, add the effect with Claude, and ship 3x more ad edits.

[Start 14-day free trial](https://www.recharm.com/get-started)