unpackrgb565.py

from PIL import Image
import struct

# https://msdn.microsoft.com/en-us/library/windows/desktop/dd390989(v=vs.85).aspx
red_mask = 0xF800;
green_mask = 0x7E0;
blue_mask = 0x1F;

def rgb565pixunpack(pixel):
    r = (pixel & red_mask) >> 11;
    g = (pixel & green_mask) >> 5;
    b = (pixel & blue_mask);
    return r, g, b

# https://github.com/iPodLinux/hotdog/blob/master/hotdog_ipg.c
def unpack(fc):
    width = struct.unpack_from('<i', fc[0:4])[0]
    height = struct.unpack_from('<i', fc[4:8])[0]
    id = struct.unpack_from('<i', fc[8:12])[0]
    other = struct.unpack_from('<i', fc[12:16])[0]

    if id != 4097:
        raise Exception("not rgb565 but %d"%id)

    img = Image.new('RGB', (width, height), "black")
    pixels = img.load()
    fc = fc[16:]
    for i in range(width):
        for j in range(height):
            pixel = struct.unpack_from('<H', fc)[0]
            pixels[i,j] = rgb565pixunpack(pixel)
            fc = fc[2:]

    return img


if __name__ == '__main__':
    import sys
    f = open(sys.argv[1], 'rb')
    img = unpack(f.read())
    f.close()
    img.show()