How to add a scrolling ticker with Claude

Add a scrolling ticker to input.mp4 (540x960). From 0.5 seconds to the end, show a full-width yellow (255, 210, 0) band 8% of the frame height tall, centered 82% down the frame, fading in over 0.2 seconds. On it, "FREE SHIPPING  •  NEW FORMULA  •  BACK IN STOCK  •  " repeated end to end in near-black (20, 20, 20) bold, text 7.5% of the frame width high and vertically centered in the band, scrolls from right to left at 40% of the frame width per second: the first letter enters at the band's right edge at 0.5 seconds and the copies follow with no gap, so the text never runs out. Nothing shows before 0.5 seconds and the rest of the frame is left as it is. 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
"""Scrolling ticker: a yellow band near the bottom with black text crawling endlessly from right to left.

Usage: python3 scrolling-ticker.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

TEXT = "FREE SHIPPING  •  NEW FORMULA  •  BACK IN STOCK  •  "
START = 0.5              # second the band appears and the text starts entering from the right
FADE = 0.2               # seconds the band takes to fade in
SPEED = 0.4              # scroll speed, in frame widths per second
Y = 0.82                 # band center (0 = top, 1 = bottom)
BAND = 0.08              # band height as a share of the frame height
SIZE = 0.075             # text height as a share of the frame width
COLOR = (255, 210, 0)    # band color
INK = (20, 20, 20)       # 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 text_strip():
    """The band as one long image: a frame width of plain band, then TEXT repeated for as far as it will scroll."""
    font = ImageFont.truetype(FONT_FILE, round(w * SIZE))
    loop = round(font.getlength(TEXT))
    copies = math.ceil(duration * SPEED * w / loop) + 1
    img = Image.new("RGBA", (w + copies * loop, round(h * BAND)), COLOR)
    draw = ImageDraw.Draw(img)
    for i in range(copies):
        draw.text((w + i * loop, img.height / 2), TEXT, font=font, anchor="lm", fill=INK)
    return img


def overlay(t):
    img = Image.new("RGBA", (w, h))
    if t < START:
        return img
    x = round((t - START) * SPEED * w)
    band = strip.crop((x, 0, x + w, strip.height))
    band.putalpha(round(255 * min((t - START) / FADE, 1)))
    img.paste(band, (0, round(h * Y - strip.height / 2)))
    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)
strip = text_strip()
render(src, out)