In this category, different pixel formats are explained - but what are pixel formats?
Anyone who talks about pixel formats necessarily means the color representation of the pixels, since this is the primary information of pixels. These are often different color channels with different resolutions, from which the color depth results.
The resolution of such a color channel is specified in bits; the value range for a color channel is accordingly from 0 to (2number of bits - 1). The color depth results from the sum of all bits of the color channels. 32 bit color depth can be composed, for example, by 4 color channels of 8 bits each - or by 3 color channels of 10 bits each plus 2 unused bits for padding.
Padding is a method of easily calculating memory addresses by using certain bits unused or otherwise.