How to add a live stream overlay with Claude

Make input.mp4 look like a live stream. From 0.5 seconds (fading in over 0.25 seconds), put a red (230, 30, 45) pill badge reading "LIVE" in white with a white dot before it, 7.2% of the frame width tall, with its top-left corner 4% across and 3.5% down; right next to it, 2% of the width further right, a translucent black pill with a white eye icon and a viewer count that starts at 1,248 and climbs by 60 a second. Then add five comments, one every 0.9 seconds from 1.0 seconds: jess_r "is it good for oily skin?", dani.b "just ordered two", sam_lee "the glow is unreal", priya.m "link please!!", tom.w "restocked yet?". Each is a translucent black pill 11% of the frame width tall, left edge 4% across, with a colored circle avatar showing the username's first letter, the username in small light gray bold text above the message in white bold text. The newest comment slides up into place with its bottom at 90% down over 0.25 seconds and pushes the older ones up one row; keep four on screen and fade out the oldest. 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
"""Live stream overlay: a red LIVE badge, a climbing viewer count and comments that scroll up the left side.

Usage: python3 live-stream-overlay.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

COMMENTS = [("jess_r", "is it good for oily skin?"),   # (username, message), one arriving every GAP seconds
            ("dani.b", "just ordered two"),
            ("sam_lee", "the glow is unreal"),
            ("priya.m", "link please!!"),
            ("tom.w", "restocked yet?")]
START = 0.5              # second the badge and viewer count appear
FIRST = 1.0              # second the first comment arrives
GAP = 0.9                # seconds between comments
SLIDE = 0.25             # seconds a comment takes to slide in
SHOWN = 4                # comments on screen at once; older ones fade out at the top
VIEWERS = 1248           # viewer count at START; it climbs by RISE a second
RISE = 60
RED = (230, 30, 45)      # LIVE badge 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")
AVATARS = [(255, 159, 67), (72, 219, 251), (29, 209, 161), (156, 136, 255), (254, 202, 87)]


def pill(size, fill):
    img = Image.new("RGBA", size)
    ImageDraw.Draw(img).rounded_rectangle([0, 0, size[0] - 1, size[1] - 1], radius=size[1] // 2, fill=fill)
    return img


def live_badge():
    font = ImageFont.truetype(FONT_FILE, round(w * 0.042))
    bh = round(w * 0.072)
    img = pill((round(font.getlength("LIVE") + bh * 1.35), bh), RED + (255,))
    draw = ImageDraw.Draw(img)
    r = bh * 0.13
    draw.ellipse([bh * 0.42 - r, bh / 2 - r, bh * 0.42 + r, bh / 2 + r], fill="white")
    draw.text((bh * 0.72, bh / 2), "LIVE", font=font, anchor="lm", fill="white")
    return img


def viewer_pill(count):
    font = ImageFont.truetype(FONT_FILE, round(w * 0.038))
    bh = round(w * 0.072)
    text = f"{count:,}"
    img = pill((round(font.getlength(text) + bh * 1.45), bh), (0, 0, 0, 140))
    draw = ImageDraw.Draw(img)
    cx, cy = bh * 0.5, bh / 2
    draw.ellipse([cx - bh * 0.22, cy - bh * 0.13, cx + bh * 0.22, cy + bh * 0.13], outline="white", width=2)
    draw.ellipse([cx - bh * 0.07, cy - bh * 0.07, cx + bh * 0.07, cy + bh * 0.07], fill="white")
    draw.text((bh * 0.9, cy), text, font=font, anchor="lm", fill="white")
    return img


def comment(i):
    user, message = COMMENTS[i]
    name_font = ImageFont.truetype(FONT_FILE, round(w * 0.032))
    text_font = ImageFont.truetype(FONT_FILE, round(w * 0.04))
    bh = round(w * 0.11)
    width = round(bh * 1.15 + max(name_font.getlength(user), text_font.getlength(message)) + bh * 0.4)
    img = pill((width, bh), (0, 0, 0, 120))
    draw = ImageDraw.Draw(img)
    draw.ellipse([bh * 0.14, bh * 0.14, bh * 0.86, bh * 0.86], fill=AVATARS[i % len(AVATARS)])
    draw.text((bh / 2, bh / 2), user[0].upper(), font=name_font, anchor="mm", fill="white")
    draw.text((bh * 1.05, bh * 0.3), user, font=name_font, anchor="lm", fill=(205, 205, 205))
    draw.text((bh * 1.05, bh * 0.68), message, font=text_font, anchor="lm", fill="white")
    return img


def ease(p):
    p = min(max(p, 0), 1)
    return 1 - (1 - p) ** 3


def faded(img, alpha):
    if alpha >= 1:
        return img
    out = img.copy()
    out.putalpha(out.getchannel("A").point(lambda a: round(a * alpha)))
    return out


def overlay(t):
    img = Image.new("RGBA", (w, h))
    if t < START:
        return img
    shown = ease((t - START) / SLIDE)
    x, y = round(w * 0.04), round(h * 0.035)
    img.alpha_composite(faded(badge, shown), (x, y))
    img.alpha_composite(faded(viewer_pill(VIEWERS + int((t - START) * RISE)), shown), (x + badge.width + round(w * 0.02), y))
    bottom, row = h * 0.9, bubbles[0].height * 1.18
    arrivals = [FIRST + i * GAP for i in range(len(COMMENTS))]
    for i, bubble in enumerate(bubbles):
        if t < arrivals[i]:
            continue
        pushed = sum(ease((t - a) / SLIDE) for a in arrivals[i + 1:] if t >= a)   # rows later comments pushed it up
        came_in = ease((t - arrivals[i]) / SLIDE)
        alpha = came_in * min(max(SHOWN - pushed, 0), 1)
        if alpha > 0.01:
            top = bottom - bubble.height - pushed * row + (1 - came_in) * row * 0.6
            img.alpha_composite(faded(bubble, alpha), (x, round(top)))
    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)
badge = live_badge()
bubbles = [comment(i) for i in range(len(COMMENTS))]
render(src, out)