--- title: "How to add a ripple transition with Claude (tested prompt and script)" description: "Rings of water ripples spread out from the middle of clip A, bending the picture with light and dark bands, and clip B shows inside the widening wave until it fills the frame. Install one skill and ask Claude Code, or run the Python script we tested yourself." url: https://www.recharm.com/effects/ripple-transition --- # How to add a ripple transition with Claude Rings of water ripples spread out from the middle of clip A, bending the picture with light and dark bands, and clip B shows inside the widening wave until it fills the frame. Made by the script 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 ripple transition Length of the transition in seconds: 1.2 Where the ripples start, 0-1 across and down the frame: 0.5, 0.5 ``` ## 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 ripple transition. ## Settings you can change Ask Claude to change any of these, or edit them at the top of the script. | Setting | Default | What it does | | ------------ | ---------- | ------------------------------------------------------------------ | | `D` | `1.2` | Length of the transition in seconds. | | `X, Y` | `0.5, 0.5` | Where the ripples start, 0-1 across and down the frame. | | `WAVELENGTH` | `70` | Distance between ripple rings in pixels. | | `AMP` | `14` | Furthest a ripple bends the picture, in pixels. | | `AHEAD` | `60` | How far the ripples reach ahead of the wave front, in pixels. | | `BEHIND` | `200` | How far the trailing rings reach behind the wave front, in pixels. | | `EDGE` | `60` | Width of the soft edge where clip A turns into clip B, in pixels. | | `SHINE` | `28` | Brightness of the light and dark bands on the ripples. | | `FPS` | `30` | Output frame rate. | ## Without the skill Don’t want to install the skill? Paste this prompt into Claude Code and Claude writes the script itself. ``` Join clipA.mp4 and clipB.mp4 with a 1.2 second ripple transition that starts 1.2 seconds before clipA.mp4 ends, so the output is A's length plus B's length minus 1.2 seconds (10.8 seconds for two 6 second clips; B starts from its first frame when the transition starts). Use Python with numpy and OpenCV (cv2.remap), working frame by frame at 30fps and fitting B to A's size first. On each transition frame, with progress p from 1/36 to 1: a wave front grows from the center of the frame at radius R = p * (distance from the center to a corner + 60) pixels. For every pixel at distance r from the center, let d = r - R, strength = sin(pi * p) * exp(-(d / s)^2) with s = 60 pixels when d > 0 (ahead of the front) and 200 pixels behind it, and phase = 2 * pi * d / 70. Bend both clips radially by sampling each pixel from 14 * strength * sin(phase) pixels closer to the center (reflect at the borders). Show B inside the front and A outside it, mixing with weight clip(0.5 - d / 60, 0, 1) for B, then add 28 * strength * cos(phase) to all three channels so the rings get light and dark bands like water. Leave every frame outside the transition untouched, so clip A is clean until 4.8 seconds and clip B is clean from 6.0 seconds. Crossfade the audio over the same 1.2 seconds. Keep the audio and save it as output.mp4 (H.264, yuv420p). ``` ## Run it without Claude This is the exact script we tested. Save it as `ripple-transition.py` and run: ``` python3 ripple-transition.py clipA.mp4 clipB.mp4 output.mp4 ``` ``` #!/usr/bin/env python3 """Ripple transition: rings of water ripples spread out from the middle of clip A, bending the picture, and clip B shows inside the widening wave. Usage: python3 ripple-transition.py clipA.mp4 clipB.mp4 output.mp4 (both clips need an audio track) Needs ffmpeg, numpy and OpenCV (pip install numpy opencv-python-headless). """ import json import subprocess import sys import cv2 import numpy as np D = 1.2 # transition length in seconds X, Y = 0.5, 0.5 # where the ripples start (0-1 across and down the frame) WAVELENGTH = 70 # distance between ripple rings in pixels AMP = 14 # furthest a ripple bends the picture, in pixels AHEAD = 60 # how far the ripples reach ahead of the wave front, in pixels BEHIND = 200 # how far the trailing rings reach behind it, in pixels EDGE = 60 # width of the soft edge where A turns into B, in pixels SHINE = 28 # brightness of the light and dark bands on the ripples FPS = 30 def probe(path): info = json.loads(subprocess.check_output(["ffprobe", "-v", "error", "-select_streams", "v:0", "-show_entries", "stream=width,height:format=duration", "-of", "json", path])) return info["streams"][0]["width"], info["streams"][0]["height"], float(info["format"]["duration"]) def frames(path): """Every frame of a clip, fitted to A's size at 30fps, as an RGB array.""" fit = f"scale={w}:{h}:force_original_aspect_ratio=increase,crop={w}:{h},fps={FPS}" ff = subprocess.Popen(["ffmpeg", "-v", "error", "-i", path, "-vf", fit, "-f", "rawvideo", "-pix_fmt", "rgb24", "-"], stdout=subprocess.PIPE) while True: chunk = ff.stdout.read(w * h * 3) if len(chunk) < w * h * 3: return yield np.frombuffer(chunk, np.uint8).reshape(h, w, 3) def ripple(a, b, p): """Frame at progress p (0-1): a ring-shaped wave grows from (X, Y), B inside it and A outside, both bent by the ripples.""" d = r - p * reach # distance past the wave front strength = np.sin(np.pi * p) * np.exp(-(d / np.where(d > 0, AHEAD, BEHIND)) ** 2) phase = 2 * np.pi * d / WAVELENGTH push = AMP * strength * np.sin(phase) # outward (+) or inward (-) bend map_x = (xs - push * ux).astype(np.float32) map_y = (ys - push * uy).astype(np.float32) bent_a = cv2.remap(a, map_x, map_y, cv2.INTER_LINEAR, borderMode=cv2.BORDER_REFLECT) bent_b = cv2.remap(b, map_x, map_y, cv2.INTER_LINEAR, borderMode=cv2.BORDER_REFLECT) inside = np.clip(0.5 - d / EDGE, 0, 1)[..., None] out = bent_a * (1 - inside) + bent_b * inside return out + (SHINE * strength * np.cos(phase))[..., None] # light on one slope of each ring, shade on the other a_path, b_path, out = sys.argv[1:4] w, h, a_len = probe(a_path) ys, xs = np.mgrid[0:h, 0:w].astype(np.float32) dx, dy = xs - X * w, ys - Y * h r = np.hypot(dx, dy) ux, uy = dx / np.maximum(r, 1), dy / np.maximum(r, 1) reach = np.hypot(max(X, 1 - X) * w, max(Y, 1 - Y) * h) + EDGE # the front passes the farthest corner at the end start = round((a_len - D) * FPS) # first frame of the transition steps = round(D * FPS) ff = subprocess.Popen(["ffmpeg", "-y", "-v", "error", "-f", "rawvideo", "-pix_fmt", "rgb24", "-s", f"{w}x{h}", "-r", str(FPS), "-i", "-", "-i", a_path, "-i", b_path, "-filter_complex", f"[1:a][2:a]acrossfade=d={D}[au]", "-map", "0:v", "-map", "[au]", "-c:v", "libx264", "-crf", "18", "-pix_fmt", "yuv420p", "-c:a", "aac", out], stdin=subprocess.PIPE) b_frames = frames(b_path) for i, a in enumerate(frames(a_path)): if i >= start: a = ripple(a, next(b_frames), (i - start + 1) / steps) ff.stdin.write(np.clip(a, 0, 255).astype(np.uint8).tobytes()) for b in b_frames: ff.stdin.write(b.tobytes()) ff.stdin.close() if ff.wait(): sys.exit("ffmpeg failed") ``` ## More transitions - [Barn door transition **Barn door transition**](https://www.recharm.com/effects/barn-door) - [Blinds transition **Blinds transition**](https://www.recharm.com/effects/blinds-transition) - [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) ## 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)