Certainly nothing greater than 133 minutes on a standard DVD-5 disc should be accepted for presentation use. Another caveat is that, just like current CD-ROM and Video CD technology, DVD can also accommodate MPEG-1 encoding - this is particularly true of DVD-ROM.

This yields a video quality that is, at best, only as good as VHS tape. Again, read the disc label - this video quality is definitely not adequate for presentation use.

While DVD-V supports both NTSC and PAL, the same problem exists as with current technology. The player needs to be able to reproduce both standards.
Interactivity is built-in to accommodate different endings, different versions (e.g.: two cuts of the same movie, with different ratings), or different camera angles for the same scene. Basic interactive enduing is built-in, with the ability to jump to a title, chapter, or track.

For compatibility with existing television sets, DVD's MPEG-2 video resolutions and frame rates are closely tied to NTSC and PAL/SECAM video formats. Note that while DVD does use the same 16:9 aspect ratio as HDTV, this 16:9 encoding is simply wide screen, it is not HDTV.

The current DVD standard simply does not support HDTV - a new HD-DVD standard will be required to support it The two most common flavors of HDTV in the US are 720p (1280x720 at 24p, 20p, and 60p) and 1080i (1920x1080 at 24p, 30p and 60i) - 24p means 24 progressive frames/sec, and 60i means 60 interlaced fields/sec (i.e.: 30 frames/sec). These HD formats are 2.7 and 6 times the resolution of current DVD respectively, and the 60p version is twice the frame rate.

DVD has the capability to produce near-studio-quality video and better-than-CD-quality audio. DVD is vastly superior to consumer videotape and generally better than laserdisc. However, quality depends on many production factors. As compression experience and technology improves we will see increasing quality, but as production costs decrease we will also see more shoddily produced discs. Low-budget DVD's will even use MPEG-1 encoding (which is no better than VHS) instead of higher-quality MPEG-2.

DVD video is usually encoded from digital studio master tapes to MPEG-2 format. The encoding process uses "lossy" compression that removes redundant information (such as areas of the picture that don't change) and information that's not readily perceptible by the human eye. The resulting video, especially when it is complex or changing quickly, may sometimes contain visual flaws, depending on the processing quality and amount of compression. At average video data rates of 3.5 to 5 Mbps (million bits/second), compression artifacts may be occasionally noticeable. Higher data rates can result in higher quality, with almost no perceptible difference from the master at rates above 6 Mbps. As MPEG compression technology improves, better quality is being achieved at lower rates. Currently encoding is done either at CBR (constant bit-rate) or VBR (variable bit-rate) which allows more data to be stored, e.g. a scene with a lot of quick motion would be encoded at a higher bit rate than a static scene (a chart, for example).

Video from DVD sometimes contains visible artifacts such as color banding, blurriness, fuzzy dots, shimmering, missing detail. It's important to understand that the term "artifact" refers to anything that was not originally present in the picture. Artifacts are sometimes caused by poor MPEG encoding, but artifacts are more often caused by a poorly adjusted TV, bad cables, electrical interference, sloppy digital noise reduction, improper picture enhancement, poor film-to-video transfer, film grain, player faults, disc read errors, etc. Most DVD's exhibit few visible MPEG compression artifacts on a properly configured system.

DVD audio quality is superb. DVD includes the option of PCM (pulse code modulation) digital audio with sampling sizes and rates higher than audio CD. Alternatively, audio for most movies is stored as discrete, multi-channel surround sound using Dolby Digital or DTS audio compression similar to the digital surround sound formats used in theaters. As with video, audio quality depends on how well the processing and encoding was done. In spite of compression, Dolby Digital and DTS can be close to or better than CD quality.

A typical DVD-5 disc is expected to be produced with up to 133 minutes of audio and video at an average data rate of 4.7Mbps (3.5Mbps for the video portion, or 36:1 compression). This should yield good quality video, but there may be some visible compression artifacts.

The DVD-9 disc, however, will allow up to two hours of material at an average data rate of 9.5Mbps, which should be free of visible artifacts. The density of the disc vs. its running time should always be checked as an indicator of the quality of the video on the disc - a DVD-5 DVD can hold up to six hours of video and audio, if highly compressed (i.e.: over 70:1 compression).