CDA refers to CD Audio music tracks. This file format is widely used for the distribution of commercial music through compact discs. These files do not contain any information about the actual pulse code modulation. The data is encoded and stored in two types of recording methods. The first Mono requires at least 44.1 kHz of sampling rate and 16 bits of sample size whereas the second Stereo requires at least twice that of Mono. As you may have already predicted, Stereo recording requires much higher storage space compared to Mono.