HEVC or h.265 is the most advanced codec for now because it has the lowest bitrate without losing the image quality. The codec has three main features that distinguishes it from others: parallel decoding, random access to images within the video stream and larger maximum block size. HEVC is aimed to offer the same level of video quality as AVC (h.264), but with improved compression, that is why a video file compressed with the codec will be twice smaller.

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