The Channel Layout or Channel Mode of a video or audio file shows the nature of sound reproduction. In video files, this only affects the audio data stream, not the visible video or image stream.
There are two values that can be given out by the Channel Layout data: mono and stereo. This is closely linked to the number of channels since mono usually represents 1 channel and stereo 2 (or even more). The distinction between the two is thus quite obvious. Mono or monaural sound production sounds like there is only one channel and only one source and direction for the audio stream. Stereo or stereophonic sound imitates sound coming from several directions and sources which can especially well perceived when wearing headphones or using more loudspeakers.