MPEG was developed in 1993 as MPEG-1 and it was a very popular format for audio and video storage. Today it is the most compatible media format in the world. When the format first appeared, it was innovate and ahead of its time, provided relatively high quality files while reducing their size and made it easy to upload and download files by compressing them. These features allowed creating video CDs, digital TV and digital audio broadcasting. Due to its age, MPG is no longer covered by any patents, that is why both Mac and Windows applications along with many hardware support MPEG video and audio natively.

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