The subcomponents of a clip. For images, an alpha channel can contain a matte or mask image to key certain regions of the image to be transparent. Alpha Channel is the channel where the transparency values of bitmap-based images to be used in layers are stored. It can be expressed in values of 8, 10, 12, or 16 bits, depending on the format (just like the red, green, and blue channels).
For audio, a channel is a representation of sound arriving from or going to a single point. For example, a single speaker can produce one channel of audio, and a single speaker can accept one channel of audio. A digital audio file may contain multiple channels of data. Music that is mixed for headphone listening is saved as a file with two channels, one sent to the left ear, one sent to the right.