Digital audio data reduction technique. Uses the concept of frequency masking to economize on bandwidth. Dominant signals are encoded while imperceptible signals in neighboring frequency bands are discarded. This is a moderately quick data reduction technique (about 80-125 ms), and results in data reduction of 8:1 to 12:1. MPEG L2 and L3 use this scheme.
Lossy compression techniques based on the study of human perception. Perceptual coding systems identify and remove information that is least likely to be missed by the average human observer.
A method of reducing the number of bits needed to encode an audio or video signal by ignoring information unlikely to be heard or seen. Also called "lossy compression."
An approach to digital coding that records only the portions of sound or picture: that we believed to be audible or visible.
A method of processing a digital audio signal in which knowledge of auditory masking is used to predict what portions of the signal would not be heard by normal listeners. These portions are then either discarded, or more simply encoded, so that the data rate used to communicate the signal is reduced, as is the storage capacity. Several such "lossy" coding systems exist, and they all sound excellent at high data rates, degrading by different amounts in different ways as the data rate is reduced.
A digital audio coding technique that reduces the amount of data needed to produce high-quality sound. Perceptual digital audio coding takes advantage of the fact that the human ear screens out a certain amount of sound that is perceived as noise. Reducing, eliminating, or masking this noise significantly reduces the amount of data that needs to be provided.
A lossy audio compression technique used by Dolby Digital which relies on the limits of human perception—signals beyond the range of human hearing are dropped.