blind uses a raw video format with a simple container. A file begins with
an plain-text line, containing the number of frames, the width, the height,
and the pixel format, all separated by a single regular blank space, without
and leading or tailing white space. After this line, which ends with an LF,
there is a NUL-byte followed by the 4 characters "uivf" (unportable, interim
video format). This head is followed by the video frame-by-frame with row-major
frames. Pixels are independently encoded, and are encoded unscaled CIE XYZ with
non-premultiplied alpha and without any transfer-function, with values stored
in native doubles or optionally in native floats. These two configurations are
the only options, but the container format is designed so this can be changed
arbitrarily in the future.