RAW: This file type uses pulse code modulation. This method encodes information in a signal by varying the amplitude of the pulses. This limits pulse amplitude to several predifined values.
RIFF: This file type uses ADPCM(Adaptive Pulse Code Modulation). This method compresses data that has been encoded in the PCM form. It stores only the changes between the samples, not the sample themselves. This compresses PCM data by a ratio of 4:1 since it uses only 4 bits for the sample change rather than the 16 bits for the original PCM value.
MP3: This file type uses lossy compression that does not seriously degrade the quality of the sound it filters out.
jamesking1994 