--- title: "How to add a fade-in text with Claude (tested prompt and script)" description: "\"Glow in 7 days\" in white slowly brightens out of thin air above the bottle, stays for two seconds, then dims away until only the footage is left. Install one skill and ask Claude Code, or run the Python script we tested yourself." url: https://www.recharm.com/effects/fade-in-text --- # How to add a fade-in text with Claude "Glow in 7 days" in white slowly brightens out of thin air above the bottle, stays for two seconds, then dims away until only the footage is left. 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 fade-in text to input.mp4 Text: Glow in 7 days ``` ## 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 fade-in text 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 | | ------- | ----------------- | ------------------------------------- | | `TEXT` | `Glow in 7 days` | The headline. | | `START` | `0.8` | Second the fade in starts. | | `FADE` | `0.8` | Seconds each fade takes. | | `HOLD` | `2.0` | Seconds the text stays fully visible. | | `Y` | `0.12` | Text center, 0-1 down the frame. | | `COLOR` | `(255, 255, 255)` | Text color. | ## Without the skill Don’t want to install the skill? Paste this prompt into Claude Code and Claude writes the script itself. ``` Add fade-in text to input.mp4: "Glow in 7 days" in bold white (255, 255, 255), 70 pixels tall (13% of the frame width), centered horizontally 12% of the way down, with a soft dark plum (40, 20, 60) shadow 3 pixels below it blurred by 5 pixels. It's invisible until 0.8 seconds, fades in linearly to full opacity by 1.6 seconds, holds until 3.6 seconds, then fades out linearly to nothing by 4.4 seconds. 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 `fade-in-text.py` and run: ``` python3 fade-in-text.py input.mp4 output.mp4 ``` ``` #!/usr/bin/env python3 """Fade-in text: a white headline fades up from nothing, holds, then fades back out. Usage: python3 fade-in-text.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, ImageFilter, ImageFont TEXT = "Glow in 7 days" # the headline START = 0.8 # second the fade in starts FADE = 0.8 # seconds each fade takes HOLD = 2.0 # seconds the text stays fully visible Y = 0.12 # text center, 0-1 down the frame SIZE = 0.13 # text height as a share of the frame width COLOR = (255, 255, 255) # text color 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 headline(): """The text with a soft dark shadow behind it, on a transparent frame.""" img = Image.new("RGBA", (w, h)) font = ImageFont.truetype(FONT_FILE, round(w * SIZE)) shadow = Image.new("RGBA", (w, h)) ImageDraw.Draw(shadow).text((w / 2, h * Y + 3), TEXT, font=font, anchor="mm", fill=(40, 20, 60, 230)) img.alpha_composite(shadow.filter(ImageFilter.GaussianBlur(5))) ImageDraw.Draw(img).text((w / 2, h * Y), TEXT, font=font, anchor="mm", fill=COLOR) return img def opacity(t): """0 before START, up to 1 over FADE, 1 for HOLD, back down to 0 over FADE.""" return min(max((t - START) / FADE, 0), 1, max((START + 2 * FADE + HOLD - t) / FADE, 0)) def overlay(t): a = opacity(t) if a <= 0: return blank img = text.copy() img.putalpha(text.getchannel("A").point(lambda v: round(v * a))) return img 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) text = headline() blank = Image.new("RGBA", (w, h)) render(src, out) ``` ## More captions and text - [AI chat reply animation **AI chat reply animation**](https://www.recharm.com/effects/ai-chat-typing) - [Animated bar chart **Animated bar chart**](https://www.recharm.com/effects/animated-bar-chart) - [Animated checklist **Animated checklist**](https://www.recharm.com/effects/animated-checklist) - [Animated line graph **Animated line graph**](https://www.recharm.com/effects/animated-line-graph) - [Animated pie chart **Animated pie chart**](https://www.recharm.com/effects/animated-pie-chart) ## 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)