How to add a toy camera look with Claude

Give input.mp4 a toy camera look for the whole clip. 1) With ffmpeg, grade it: curves=r='0/0 0.3/0.18 0.7/0.72 1/0.95':g='0/0 0.3/0.24 0.7/0.8 1/1':b='0/0.08 0.3/0.3 0.7/0.8 1/1' (red held down so the picture leans cyan, more contrast, blue-lifted shadows), then eq=saturation=1.8. 2) Then, per frame with numpy and Pillow, make the edges soft and dark like a cheap plastic lens. For each pixel, let r be its distance from the frame center with x measured in half-widths and y in half-heights, divided by sqrt(2) so r is 0 at the center and 1 at the corners; s = clamp((r - 0.45) / 0.55, 0, 1) and edge = s*s*(3 - 2*s). Blend the sharp frame with a copy blurred by Pillow's GaussianBlur(7) using edge as the blurred copy's weight, then multiply by 1 - 0.85*edge, so the middle stays sharp and untouched and the corners are blurred and 85% darker. The cool blue-white backdrop (around RGB 193, 203, 216) should come out cyan-turquoise (around RGB 163, 213, 221), the frame corners should be around brightness 35, and the middle of the frame should stay as bright as before. Don't add any text (if you ever do, draw it with Pillow, not ffmpeg's drawtext). Keep the size (540x960), 30fps, the 6 second length and the audio. Encode H.264 yuv420p and save it as output.mp4.

#!/usr/bin/env python3
"""Toy camera: punchy, oversaturated cyan-shifted color, with corners that go soft and then dark like a cheap plastic lens.

Usage: python3 toy-camera.py input.mp4 output.mp4
Needs ffmpeg, numpy and Pillow (pip install numpy pillow).
"""
import json
import subprocess
import sys

import numpy as np
from PIL import Image, ImageFilter

RED = "0/0 0.3/0.18 0.7/0.72 1/0.95"      # red S-curve, held down so the picture leans cyan
GREEN = "0/0 0.3/0.24 0.7/0.8 1/1"        # green S-curve: more contrast
BLUE = "0/0.08 0.3/0.3 0.7/0.8 1/1"       # blue S-curve with lifted blacks, so shadows go blue
SATURATION = 1.8                          # extra color on top of the curves (1 leaves it as is)
BLUR = 7                                  # Gaussian blur radius, in pixels, at the corners
DARKEN = 0.85                             # how much darker the very corners get (0.85 = 85% darker)
CLEAR = 0.45                              # sharp, undarkened middle, as a share of the distance to the corner


def probe(path):
    info = json.loads(subprocess.check_output(["ffprobe", "-v", "error", "-select_streams", "v:0", "-show_entries",
                                               "stream=width,height", "-of", "json", path]))
    return info["streams"][0]["width"], info["streams"][0]["height"]


def falloff():
    """0 in the middle of the frame, rising smoothly to 1 at the corners."""
    y, x = np.mgrid[0:h, 0:w].astype(np.float32)
    r = np.hypot((x - w / 2) / (w / 2), (y - h / 2) / (h / 2)) / np.sqrt(2)
    s = np.clip((r - CLEAR) / (1 - CLEAR), 0, 1)
    return (s * s * (3 - 2 * s))[:, :, None]


def render(src, out):
    grade = f"fps=30,curves=r='{RED}':g='{GREEN}':b='{BLUE}',eq=saturation={SATURATION}"
    reader = subprocess.Popen(["ffmpeg", "-v", "error", "-i", src, "-vf", grade,
                               "-f", "rawvideo", "-pix_fmt", "rgb24", "-"], stdout=subprocess.PIPE)
    writer = subprocess.Popen(["ffmpeg", "-y", "-v", "error", "-f", "rawvideo", "-pix_fmt", "rgb24", "-s", f"{w}x{h}",
                               "-r", "30", "-i", "-", "-i", src, "-map", "0:v", "-map", "1:a?",
                               "-c:v", "libx264", "-crf", "18", "-pix_fmt", "yuv420p", "-c:a", "copy", "-shortest", out],
                              stdin=subprocess.PIPE)
    edge = falloff()
    shade = 1 - DARKEN * edge
    while raw := reader.stdout.read(w * h * 3):
        img = Image.frombuffer("RGB", (w, h), raw)
        sharp = np.asarray(img, np.float32)
        soft = np.asarray(img.filter(ImageFilter.GaussianBlur(BLUR)), np.float32)
        frame = (sharp * (1 - edge) + soft * edge) * shade
        writer.stdin.write(np.clip(frame, 0, 255).astype(np.uint8).tobytes())
    writer.stdin.close()
    if reader.wait() or writer.wait():
        sys.exit("ffmpeg failed")


src, out = sys.argv[1:3]
w, h = probe(src)
render(src, out)