Audio can be faded up or down in volume, mixed with music, sound effects, narration, and sweetened in numerous ways. The VCR makes heads spin - Inside your camcorder is a miniature videocassette recorder. It records audio, maybe with high fidelity, and records video. It doesn't care where the audio and video come from. Once the VCR receives audio and video signals, regardless of their sources, it has the job of recording them on the tape.
Video signals consist of many electrical vibrations.
Each piece of data represents an electrical vibration, and somehow that vibration needs to be recorded on the tape. Audio, on the other hand, consists of only several thousand vibrations per second, making it easier to record. Since audio is easier, let's explain audio first. Tape, which is a long ribbon of plastic impregnated with metal particles, slides over the audio record head allowing each of the magnetic vibrations to magnetize a tiny portion of the tape. Let's use our imaginations again.