 | Over two hours of play time, 8 on a 'flippy' or two sided disc or a dual-layer disc |
| Often features pan and scan and letterbox on the same DVD |
| Often supports regular TV aspect ratio of 4,3 and widescreen TVs with 16,9 |
| Up to eight tracks of digital audio permitting alternate languages and/or commentary
tracks from actors or directors. |
| Up to 32 subtitle tracks. |
| Up to nine camera angles. |
| Automatic 'seamless branching' permitting multiple storylines or ratings. For example,
the DVD Kalifornia permits the selection of the 'R' rated or unrated versions via a menu
selection. |
| Menu and other interactive features including some simple interactive quizzes or games. |
| Random access and programmability permitting selection of any track, random track
play, repeat of tracks or portions of tracks and/or 'bookmarking', i.e. user control return
points. |
| Forward and reverse single frame stepping. |
| Not susceptible to magnetic fields. Resistant to heat. |
| Six-channel analog output from internal audio decoder. |
| Recognition and output of DTS Digital Surround audio tracks |
| Parental lock which refuses playback of objectionable tracks or the whole disc. |
| Ability to read dual layer discs. |
Video Resolution
Currently, a DVD offers about 480 lines of resolution. This is
double the 240 lines of the VHS format. Once HDTV gets going the DVD specs permit an
upgrade (with newer players) to 720 lines of resolution. The 480 lines is best seen on a
progressing DVD player which can convert the 480 interlaced video
(480I) into 480 line progressive format (480p). The advantage
of this is the progressive display has a 31.5 kHz or higher scans rate which eliminates
all traces of scan delay and provides a more film like picture. Some of the more advanced
progressive scan sets now offer 1080 lines of resolution designated as 1080p sets.
Compatibility with Standard CDs
Most DVD players are fully compatible with standard audio CDs (CD-DA) as long as the CD
was produced in accordance with the 'Red Book' standards. There are problems with
some CD-Rs created under the 'Orange Book' part II standards. If you are buying a
DVD for your computer be sure that it is a type 2 DVD ROM. This is
especially important if you own a CD burner or often use CDs created on such a burner.
(Look for a gold or greenish color instead of the normal CD silver.) Although all current
DVD manufacturers permit the reading of CDs it is not part of the DVD
specifications. Normal CD-ROMs created under the 'Yellow Book'
standards are readable in DVD ROMS. CD-Rewritable created in accordance with the 'Orange
Book' Part III has a lower reflectivity difference, requiring new
automatic-gain-control (AGC) circuitry. CD-RW discs can't be read by most existing CD-ROM
drives and CD players. The new "MultiRead" standard addresses this, and
some DVD manufacturers have suggested they will support it. The optical circuitry in even
first-generation DVD-ROM drives and DVD players is usually able to read CD-RW discs, since
CD-RW does not have the "invisibility" problem of CD-R
Please be aware that DVDs cannot be played in CD-ROMs or audio CD players. The
pits are too small to be read, the track distances differ etc.
![disc[1].gif (36230 bytes)](images/disc1.gif)