How to add a pop-in text with Claude

Add a pop-in headline to input.mp4: "NEW FORMULA" in black on a yellow (255, 214, 0) rounded box, centered 20% of the way down, growing from nothing at 0.3 seconds to full size by 0.65 seconds with a slight overshoot, then staying. 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
"""Pop-in text: a headline on a yellow box springs out of nothing, overshoots a little and settles.

Usage: python3 pop-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, ImageFont

TEXT = "NEW FORMULA"
START = 0.3              # second the pop starts
POP = 0.35               # seconds the pop takes
SIZE = 0.09              # text height as a share of the frame width
Y = 0.20                 # where the box's center sits (0 = top, 1 = bottom)
BOX = (255, 214, 0)      # box 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 badge():
    """The headline on its box, drawn once at full size."""
    font = ImageFont.truetype(FONT_FILE, round(w * SIZE))
    pad = round(w * SIZE * 0.45)
    x0, y0, x1, y1 = ImageDraw.Draw(Image.new("RGBA", (1, 1))).textbbox((0, 0), TEXT, font=font)
    img = Image.new("RGBA", (x1 - x0 + 2 * pad, y1 - y0 + 2 * pad))
    draw = ImageDraw.Draw(img)
    draw.rounded_rectangle([0, 0, img.width - 1, img.height - 1], radius=pad // 2, fill=BOX)
    draw.text((pad - x0, pad - y0), TEXT, font=font, fill="black")
    return img


def overlay(t):
    img = Image.new("RGBA", (w, h))
    scale = ease_out_back((t - START) / POP) if t >= START else 0
    if scale > 0.02:
        b = full.resize((max(1, round(full.width * scale)), max(1, round(full.height * scale))), Image.LANCZOS)
        img.alpha_composite(b, (round(w / 2 - b.width / 2), round(h * Y - b.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)
full = badge()
render(src, out)