The Digital Fact Book - Quantel

DTo maximize quality and playing time DVD-Video uses variable bit rate (VBR) MPEG-2coding where the bit rate varies with the demands of the material. Typically a 525/60 TVformat, 24 f/s movie would use an average bit rate of 3.5 Mb/s, but for sections with agreat deal of movement it could peak at 8 or 9 Mb/s. Only 24 f/s are coded onto the disk,the 3:2 pull-down conversion to 30 f/s taking place in the player. This allows a 120-minute24 f/s movie to fit on a DVD-5. To store video (not film) with 50 or 60 discrete fields persecond, the bit rate tends to average around 6 or 7 Mb/s, but again depends on the runningtime, original material and desired picture quality.Multi-channel audio DVD-Video supports PCM, MPEG and Dolby Digital audio, foranything from mono, stereo, Dolby Surround to 5.1 channels. Digital Theatre Sound (DTS)and Sony Dynamic Digital Sound (SDDS) are options. Up to eight separate audio streamscan be supported, allowing multiple languages, audio description, director’s commentary,etc. For example, a release may have 5.1 Dolby Digital English, two-channel Dolby DigitalSpanish with Dolby Surround, and mono French.Region coding Disks can be region-coded and so only play in a particular region(as defined in the player), a set of regions or be ‘code-free’.The region numbers are:1. Canada, US, US Territories2. Japan, Europe, South Africa, Middle East (including Egypt)3. Southeast Asia, East Asia (including Hong Kong)4. Australia, New Zealand, Pacific Islands, Central America, South America, Caribbean5. Former Soviet Union, Indian Subcontinent, Africa (also North Korea, Mongolia)6. ChinaSee also: HD DVD, Blu-ray Disc, Dolby Digital, Dolby Surround, MPEG-2, MPEG-4DVEDigital Video Effects (systems). These have been supplied as separate machines butincreasingly are being included as an integral part of systems. The list of effects variesbut will always include picture manipulations such as zoom and position and may go on torotations, 3D perspective, page turns, picture bending and curls, blurs, etc. Picture qualityand control also vary widely depending on the processing techniques used.See also: Axis, Global76