How to add a text scramble reveal with Claude

Add a text scramble reveal to input.mp4: the line "GLOW IN 7 DAYS" in bold white with a black outline, its height 10% of the frame width, centered across and 13% down. From 0.5 seconds every letter slot (not the spaces) shows a random symbol from A-Z, 0-9 and #%&@$*?<>/+= in green (60, 255, 140), changing 15 times a second; each slot stays where its final letter sits so the line never shifts. Starting at 0.9 seconds the slots lock into their real white letters left to right, one every 0.08 seconds, so the whole line reads by about 2 seconds and then stays. Nothing shows before 0.5 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.

#!/usr/bin/env python3
"""Text scramble reveal: random green symbols flicker in every letter slot, then lock into a white headline left to right.

Usage: python3 text-scramble-reveal.py input.mp4 output.mp4
Needs ffmpeg and Pillow (pip install pillow).
"""
import json
import math
import random
import subprocess
import sys
from pathlib import Path

from PIL import Image, ImageDraw, ImageFont

TEXT = "GLOW IN 7 DAYS"
START = 0.5                  # second the scrambled symbols appear
FIRST_LOCK = 0.4             # seconds of pure scramble before the first letter locks
STAGGER = 0.08               # seconds between one letter locking and the next
FLICKER = 15                 # times a second each unlocked slot changes symbol
SYMBOLS = "ABCDEFGHJKLMNPQRSTUVXYZ0123456789#%&@$*?<>/+="
SIZE = 0.10                  # text height as a share of the frame width
Y = 0.13                     # text center, as a share of the frame height
SCRAMBLE_COLOR = (60, 255, 140)  # color of the symbols still scrambling
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 slot_centers():
    """Where each letter of the finished line sits, so symbols flicker in place and the line never shifts."""
    x = (w - font.getlength(TEXT)) / 2
    centers = []
    for i, ch in enumerate(TEXT):
        width = font.getlength(TEXT[:i + 1]) - font.getlength(TEXT[:i])
        centers.append(x + width / 2)
        x += width
    return centers


def overlay(t):
    img = Image.new("RGBA", (w, h))
    if t < START:
        return img
    draw = ImageDraw.Draw(img)
    tick = int(t * FLICKER)
    for i, (ch, cx) in enumerate(zip(TEXT, centers)):
        if ch == " ":
            continue
        if t >= START + FIRST_LOCK + i * STAGGER:
            glyph, color = ch, "white"
        else:
            glyph, color = random.Random(tick * 1000 + i).choice(SYMBOLS), SCRAMBLE_COLOR
        draw.text((cx, h * Y), glyph, font=font, anchor="mm", fill=color,
                  stroke_width=round(w * 0.007), stroke_fill="black")
    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)
font = ImageFont.truetype(FONT_FILE, round(w * SIZE))
centers = slot_centers()
render(src, out)