As you ready about HD DVD and Blu-ray movies, you’ll come across many acronyms describing new technologies and standards. We’ve provided a glossary of some of the most common terms.

AACS
The Advanced Access Content System (AACS) is a copy protection standard use with HD DVD and Blu-ray discs delivering movie content.

Blu-ray Disc
Blu-ray is a new high-definition video disc standard that offers up to six times the visual detail of traditional DVDs. Blu-ray discs can hold up to 25GB on a single-layer disc and 50GB on a dual-layer disc. This extra capacity combined with the use of advanced video and audio codecs offers consumers an amazing HD experience.

Bitstream Processing (BSP)
Variable-length decoding of entropy coding schemes such as CABAC, and CAVLC.

CABAC
Context Adaptive Binary Arithmetic Coding (CABAC) is a lossless entropy coding system used in H.264 video compression. Decoding it is extremely costly and inefficient to implement as a pure software implementation both in terms of processing cycles and system power.

CAVLAC
CAVLC is a five-letter abbreviation standing for context-adaptive variable-length coding. CAVLC is a form of entropy coding used in H.264/AVC/MPEG-4 video/audio encoding and is an inherently lossless compression technique. Thus a file can be encoded this way without causing any quality loss.

DEBLOCKING
Technique used to minimize the block boundary artifacts: in-loop algorithm is used in H.264, and both in-loop and out-of-loop algorithms are used in VC-1.

DVI
Digital Visual Interface (DVI) is a video interface standard designed to maximize the visual quality of digital display devices such as flat panel LCD computer displays and digital projectors.

HDCP
High-Bandwidth Digital Content Protection (HDCP) is a form of copy protection technology designed to prevent transmission of non-encrypted high-definition content as travels across DVI or HDMI digitial connections. Graphics cards that are designed to meet the HDCP specification are necessary to view Blu-ray and HD DVD encrypted movies.

HD DVD
HD DVD is a new high definition video disc standard that delivers up to six times the image quality of standard DVD movies. HD DVD promises a major advancement over video discs in the same way that HDTVs deliver superior image detail over standard TV.

HDMI
High Definition Multimedia Interface (HDMI) is a new interface standard for consumer electronics devices that combines HDCP-protected digital video and audio into a single, consumer-friendly connector.

IDCT
Inversing the Discrete Cosine Transformations used in video compression to encode the differences between two frames.

Motion Compensation
Reconstruction of sections of predicted frames by using reference frames and motion vectors that describe where and how much the section has moved from the its position in the reference frame.