Apple Mac 5260/100 - Manual (Page 16)

Basics TV/FM Radio Tuner Card - 14
The TV picture is in its own window on the desktop, and the
default size of the window is 320x240 pixels. The picture
can be resized from 160x120 pixels up to 640x480 pixels.
The resolution of the picture does not increase at larger
window sizes, but the image is expanded by doubling the
pixel size or by two-dimensional linear interpolation.
The TV signal is carried in YUV format for improved picture
clarity. The YUV format is 16-bit, with 8 bits for the Y
(luminance) channel and 8 bits for the U and V
(chrominance) channels to share by multiplexing. The
picture is clearer because the YUV format carries more
levels of luminance information.