Data Compression Techniques for Digital Video Recording

摘要

An overview of investigations on compression techniques for experimental digitalvideo recorders of the last decade, which also reviewed HDTV (High Definition Television) consumer recording, electronic still picture storage, and low rate multimedia applications, is presented. An intraframe Discrete Cosine Transform (DCT) coding system for compressing standard resolution YUV component TV signals with a factor of 4 to 6 to a bit rate of 20 to 25 Mbit/s is described. This architecture was employed successfully in an experimental digital recording system. Measures for enhancing the system robustness for both errors and during the trick modes are investigated. Bit rate reduction and recording of HDTV signals for consumer applications was studied in two ways: a gradual introduction of HDTV recording based on already existing digital TV recorders; and HDTV recording with TV recording features on the same (small) recording mechanics. In such a system, HDTV signals can be independently coded from the TV signals, but they need to be more compressed than TV signals, because feasible recording mechanics allow only for the double or triple bit rate used for TV signals. The additional bit rate reduction was obtained by applying motion compensated DCT coding every second video frame. This technique was combined with intraframe DCT coding in every first frame, thereby creating a feasible system which still allows for editing and trick modes on two frame basis, and which offers a compressed HDTV bit rate around 50 Mbit/s.