CIMM DEFINITION: A compression technique that can be applied to any content whether an image, audio or video, that in the process, creates degradation because some of the data is discarded. Can sometimes lead to over compression.

2: The distortion that is introduced into audio or video by the compression algorithm (codec). Compressed images may have stray pixels that were not present in the original image. See codec. Aspect ratio – the width-to-height ratio of a picture or video frame. TV broadcasts at a 4:3 (1.33:1) aspect ratio; digital TV will be broadcast with a 16:9 (1.78:1) ratio; and most feature films are shot in at least a 1.85:1 ratio. IMUs have an aspect ratio of 6:5 (330x 250; 336 x 280; and 180 x 150). (Source: IAB)