The pixel data represents "printing density", the density that is seen by the print film.

After this line follows the binary pixel data.

A raw image is the unprocessed set of pixel data directly from the camera's sensor, often saved in a proprietary format.

Over time the format has been improved and there is support for compression of some parts of the pixel data.

If image content is to be identified to understand the meaning of an image, the only available independent information is the low-level pixel data.

ETC1 takes 4x4 groups of pixel data and compresses each into a single 64-bit word.

Before compressing, non-destructive delta filters are applied on the pixel data.

These are parallel data lines that carry pixel data.

For example, every re-exposure of a window or background region needs to have its (compressed) pixel data resent over the network.

In this way x11vnc can manage the scratch region to store and retrieve pixel data without having to resend it over the network.