--- title: "How to add a star rating animation with Claude (tested prompt and script)" description: "A dark card pops up near the bottom of the frame reading \"4.9\" beside five empty star outlines, which fill gold one at a time from left to right. Install one skill and ask Claude Code, or run the Python script we tested yourself." url: https://www.recharm.com/effects/star-rating-animation --- # How to add a star rating animation with Claude A dark card pops up near the bottom of the frame reading "4.9" beside five empty star outlines, which fill gold one at a time from left to right. Made by the script on this page, from our own test clip. ## 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 ``` Add a star rating animation to input.mp4 Reviews: 2,148 reviews ``` ## 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 star rating animation 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 script. | Setting | Default | What it does | | ------------------ | --------------- | ----------------------------------------------------------- | | `RATING` | `4.9` | The score shown; the last star fills by its fraction. | | `REVIEWS` | `2,148 reviews` | Small line under the stars. | | `START` | `0.5` | Second the card pops up. | | `FIRST_STAR, STEP` | `1.0, 0.3` | Second the first star fills, and the seconds between stars. | | `Y` | `0.80` | Card center, as a share of the frame height. | | `GOLD` | `(255, 185, 0)` | Filled star color. | ## Without the skill Don’t want to install the skill? Paste this prompt into Claude Code and Claude writes the script itself. ``` Add an animated star rating to input.mp4. At 0.5 seconds a dark rounded card pops up over 0.3 seconds with a slight overshoot: 84% of the frame width, 30% as tall as it is wide, centered across and 80% down, color (22, 22, 30) at 88% opacity, corner radius a fifth of its height. On its left, "4.9" in white bold type 56% of the card height tall; to its right, five star outlines in grey (150, 150, 160) spread evenly from 38% to 94% across the card at 40% of its height, each star 34% of the card height from point to point, with "2,148 reviews" in light grey (185, 185, 195) under them. Starting at 1.0 seconds, the stars fill solid gold (255, 185, 0) one by one, left to right, every 0.3 seconds; each starts 35% larger and settles to size over 0.2 seconds, and the fifth fills only its left 90% to match 4.9. The card then stays to the end. Use Python with Pillow to draw it and ffmpeg to put it on the video (don't rely on ffmpeg's drawtext filter), keep the audio, and save it as output.mp4. ``` ## Run it without Claude This is the exact script we tested. Save it as `star-rating-animation.py` and run: ``` python3 star-rating-animation.py input.mp4 output.mp4 ``` ``` #!/usr/bin/env python3 """Star rating animation: a dark rating card pops up and five gold stars fill in one by one beside "4.9". Usage: python3 star-rating-animation.py input.mp4 output.mp4 Needs ffmpeg and Pillow (pip install pillow). """ import json import math import subprocess import sys from pathlib import Path from PIL import Image, ImageDraw, ImageFont RATING = 4.9 # the score; the last star fills by its fraction (0.9 of a star for 4.9) REVIEWS = "2,148 reviews" # small line under the stars START = 0.5 # second the card pops up POP = 0.3 # seconds the card's pop takes FIRST_STAR = 1.0 # second the first star fills STEP = 0.3 # seconds between stars WIDTH = 0.84 # card width as a share of the frame width (centered across) Y = 0.80 # card center, as a share of the frame height GOLD = (255, 185, 0) # filled star color CARD = (22, 22, 30, 225) # card color and opacity FONTS = ["/System/Library/Fonts/Supplemental/Arial Bold.ttf", # macOS "/usr/share/fonts/truetype/dejavu/DejaVuSans-Bold.ttf", # Linux "C:/Windows/Fonts/arialbd.ttf"] # Windows FONT_FILE = next((f for f in FONTS if Path(f).exists()), None) or sys.exit("No bold font found: add one to FONTS") def star_points(cx, cy, r): """The ten corners of a five-pointed star, point up.""" return [(cx + (r if i % 2 == 0 else r * 0.42) * math.sin(i * math.pi / 5), cy - (r if i % 2 == 0 else r * 0.42) * math.cos(i * math.pi / 5)) for i in range(10)] def card_layout(): """The card with the score, empty star outlines and review count, plus where each star sits on it.""" cw = round(w * WIDTH) ch = round(cw * 0.30) img = Image.new("RGBA", (cw, ch)) draw = ImageDraw.Draw(img) draw.rounded_rectangle([0, 0, cw - 1, ch - 1], radius=ch // 5, fill=CARD) draw.text((ch * 0.22, ch * 0.50), f"{RATING:.1f}", font=ImageFont.truetype(FONT_FILE, round(ch * 0.56)), anchor="lm", fill="white") r = ch * 0.17 # star radius x0, gap = cw * 0.38, (cw * 0.94 - cw * 0.38) / 5 # stars span 38% to 94% of the card centers = [(x0 + gap * (i + 0.5), ch * 0.40) for i in range(5)] for cx, cy in centers: draw.polygon(star_points(cx, cy, r), outline=(150, 150, 160), width=max(2, round(r / 9))) draw.text((x0 + gap * 2.5, ch * 0.80), REVIEWS, font=ImageFont.truetype(FONT_FILE, round(ch * 0.15)), anchor="mm", fill=(185, 185, 195)) return img, centers, r def gold_star(r, fill): """A gold star on its own square, with only the left `fill` share of it colored.""" d = math.ceil(r * 2) + 2 img = Image.new("RGBA", (d, d)) ImageDraw.Draw(img).polygon(star_points(d / 2, d / 2, r), fill=GOLD) img.paste((0, 0, 0, 0), (round(d / 2 - r + 2 * r * fill), 0, d, d)) return img def overlay(t): img = Image.new("RGBA", (w, h)) if t < START: return img c = card.copy() for i, (cx, cy) in enumerate(centers): p = (t - FIRST_STAR - i * STEP) / 0.2 # each star fills with a 0.2-second pop fill = min(1.0, RATING - i) if p >= 0 and fill > 0: s = 1 + 0.35 * (1 - min(p, 1)) ** 2 # starts 35% bigger and settles g = gold_star(radius, fill) g = g.resize((round(g.width * s), round(g.height * s)), Image.LANCZOS) c.alpha_composite(g, (round(cx - g.width / 2), round(cy - g.height / 2))) scale = ease_out_back((t - START) / POP) if scale < 0.02: return img c = c.resize((max(1, round(c.width * scale)), max(1, round(c.height * scale))), Image.LANCZOS) img.alpha_composite(c, (round(w / 2 - c.width / 2), round(h * Y - c.height / 2))) return img def ease_out_back(p): """0 -> 1 with a small overshoot past 1 before settling, which reads as a 'pop'.""" p = min(max(p, 0), 1) return 1 + 2.70158 * (p - 1) ** 3 + 1.70158 * (p - 1) ** 2 def probe(path): info = json.loads(subprocess.check_output(["ffprobe", "-v", "error", "-select_streams", "v:0", "-show_entries", "stream=width,height,r_frame_rate:format=duration", "-of", "json", path])) s = info["streams"][0] num, den = s["r_frame_rate"].split("/") return s["width"], s["height"], s["r_frame_rate"], float(num) / float(den), float(info["format"]["duration"]) def render(src, out): """Draw overlay(t) on every frame of src and save to out, keeping the audio.""" ff = subprocess.Popen(["ffmpeg", "-y", "-v", "error", "-i", src, "-f", "rawvideo", "-pix_fmt", "rgba", "-s", f"{w}x{h}", "-r", rate, "-i", "-", "-filter_complex", "[0:v][1:v]overlay=shortest=1,format=yuv420p[v]", "-map", "[v]", "-map", "0:a?", "-c:v", "libx264", "-crf", "18", "-c:a", "copy", out], stdin=subprocess.PIPE) for i in range(math.ceil(duration * fps)): ff.stdin.write(overlay(i / fps).tobytes()) ff.stdin.close() if ff.wait(): sys.exit("ffmpeg failed") src, out = sys.argv[1:3] w, h, rate, fps, duration = probe(src) card, centers, radius = card_layout() render(src, out) ``` ## More ugc and social proof - [Comment reply overlay **Comment reply overlay**](https://www.recharm.com/effects/comment-reply-overlay) - [Day counter **Day counter**](https://www.recharm.com/effects/day-counter) - [Emoji rain **Emoji rain**](https://www.recharm.com/effects/emoji-rain) - [Floating hearts **Floating hearts**](https://www.recharm.com/effects/floating-hearts) - [Follow button animation **Follow button animation**](https://www.recharm.com/effects/follow-button-animation) ## Find 3x _winning ads_ Recharm cuts your ad footage into tagged, searchable clips: hooks, testimonials, product shots. 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