SP stands for short play. The speed setting and tape thickness determines the image and sound reproduction quality. This speed provides the highest quality. It uses the most amount of tape in the cassette. The amount of time available to record on cassettes varies because they have different tape lengths.
LP stands for long play. On this setting, the tape will record twice as much material as on SP. The reproduction quality is not quite as good as SP.
SLP is for super long play and records the longest amount of time. With this VCR setting, the tape records three times as long as the SP setting. The video and audio recording quality is not as good as LP.