Fauux Mystery Decoder for 2021 puzzle

blend.png

decoder.py

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
#
#    Copyright © 2021 Manoel Vilela
#
#    @project: Fauux Mystery Decoder for 2021 puzzle
#     @author: Manoel Vilela
#      @email: manoel_vilela@engineer.com
#

"""Ensure you have installed:

pip install numpy av Pillow

Execute this script after download blue.mov, green.mov and red.mov files from
fauux.neocities.org website.

This is only a part of the puzzle.

Good luck.
"""


import typing as T
import av
import numpy as np
from av.video.frame import VideoFrame
from PIL import Image

files_by_window_size = {
    "blue.mov": 8,
    "green.mov": 16,
    "red.mov": 32
}


def address_windowed(idx, x_shape, y_shape, window):
    x = window * (idx // (x_shape // window))
    y = window * (idx % (y_shape // window))
    return x, y


def video_to_array_frames(video: str) -> T.List[np.array]:
    video = av.open(video)
    frames = []
    for packet in video.demux():
        for frame in packet.decode():
            if isinstance(frame, VideoFrame):
                img = frame.to_image()  # PIL/Pillow image
                arr = np.asarray(img)  # numpy array
                frames.append(arr)
    return frames


def blend_arrays(arrays: T.List[np.array], window: int) -> np.array:
    array_shape = arrays[0].shape
    x_shape, y_shape, _ = array_shape
    array_base = np.zeros(array_shape)

    for idx, array in enumerate(arrays):
        x, y = address_windowed(idx, x_shape, y_shape, window)
        x_w = x + window
        y_w = y + window
        array_base[x:x_w, y:y_w, :] = array[x:x_w, y:y_w, :]

    return array_base


def red_blend_arrays(arrays: T.List[np.array]) -> np.array:
    array_shape = (512, 512, 3)
    x_shape, y_shape, _ = array_shape
    array_base = np.zeros(array_shape)
    window = 32

    for idx, array in enumerate(arrays):
        x, y = address_windowed(idx, x_shape, y_shape, window)
        x_w = x + window
        y_w = y + window
        array_base[x:x_w, y:y_w, :] = array

    return array_base


def convert_array_into_image(array: np.array) -> Image:
    x = array / array.max()
    return Image.fromarray((x * 255).astype(np.uint8))


def blend_windowed_video(video_file: str) -> np.array:
    print(f"Decoding... {video_file}")
    frames = video_to_array_frames(video_file)
    if video_file.startswith("red"):
        return red_blend_arrays(reversed(frames))
    else:
        return blend_arrays(frames, window=files_by_window_size[video_file])


def save_image(image: Image) -> None:
    image.save("blend.png", format="png")
    print("Saved blend.png file.")


def main():
    r = blend_windowed_video("red.mov")
    g = blend_windowed_video("green.mov")
    b = blend_windowed_video("blue.mov")
    blended_array = np.zeros((512, 512, 3))
    blended_array[:, :, 0] = r[:, :, 0]
    blended_array[:, :, 1] = g[:, :, 1]
    blended_array[:, :, 2] = b[:, :, 2]
    image = convert_array_into_image(blended_array)
    save_image(image)


if __name__ == '__main__':
    main()