Continuously Variable Slope Delta modulation is a voice coding method. It is a delta modulation with variable step size (adaptive delta modulation), first proposed by Greefkes and Riemens in 1970
MP3 is an audio format that can compress and encode an audio file. It uses the lossy compression algorithm to contain audio data. The lossy compression helps to reduce the data significantly without losing audio quality. MP3s are created using different bit rates maintaining the original quality.