SVC on Twitter    SVC on Facebook    SVC on LinkedIn

 

Here Come HD Optical Discs

THE DVD may be the most successful electronic gadget of all time. DVD players are everywhere, and they're cheap, too. Every new computer sold today has at least one DVD-ROM drive in it.

THE DVD may be the most successful electronic gadget of all time. DVD players are everywhere, and they're cheap, too. Every new computer sold today has at least one DVD-ROM drive in it.

DVD players evolved from SD interlaced playback through analog outputs to full-blown models with HD resolution video scaling through DVI and HDMI outputs. There are numerous write-once and write-many red-laser DVD formats, such as DVD-R, DVD-RW, DVD+R, DVD+RW, and even a new, dual-layer DVD format with 8.5 GB of capacity.

Now, manufacturers are setting two new blue-laser DVD formats upon us. Why? Because we now need to record and play back HDTV. Red-laser DVDs are fine for playing standard-definition video, but they don't have enough capacity to hold a two-hour HD movie, encoded in MPEG-2 at 1920x1080 resolution (or 1280x720 resolution, for that matter).

And why do we need to play back movies or other video content in an HD format? Because our fixed-pixel displays (DLP, plasma, LCD, LCoS) have gotten so large with such high pixel density that SD video just isn't good enough any more.

To complicate matters, there are two incompatible formats competing in the HD disc arena. The first is Toshiba's HD-DVD, which uses a 405 nanometer (nm) blue laser and a 36 Mb/s constant data rate for playback with disc capacities of 15 GB (single layer) and 25 GB (dual layer). NEC, Sanyo, HP, and Microsoft have also endorsed it.

The second is Blu-ray, supported by Sony, Panasonic, Pioneer, Sharp, Philips, Samsung, LG, HP, Apple, and Dell. Blu-ray also uses a 405 nm blue laser and a 36 Mb/s constant data rate. However, it has a larger numerical aperture and thus greater storage capacity, with 25 GB standard on single-layer discs and 50 GB available on dual-layer discs.

At first glance, a blue laser DVD doesn't look much different than a red-laser DVD. In the case of HD-DVD, the similarities run deeper — both RL-DVD and HD-DVD have a 0.6 mm protection layer and almost the same numerical aperture (0.6 mm for RL, 0.65 mm for HD-DVD). The lasers also sit the same height from the disc surface at 1 mm.

Blu-ray, while it offers greater capacity over HD-DVD, has a shallower protection layer (only 0.1 mm) and a much wider aperture (0.85 mm). In addition, the blue laser pickup sits almost on top of the DVD surface with a spacing of about 0.3 mm. So it's a whole different ball of wax for mastering and burning.

If you guessed that neither disc format works in the other guy's players, you win the prize! So, how can a consumer possibly know which format to go with? Which will be the winner?

Both systems support a wide range of digital codecs, including MPEG-2, MPEG-4 (AVC), and even Windows Media. No advantage there. Both will encode movies in a 1080p/24 format for the North American market, with the capability in the future to show 24p native, or double or triple to 48 Hz and 72 Hz, not to mention perform 2:3 pull-up to 60 Hz. Again, no advantage to either side.



1 2 3 Next
Browse Back Issues
BROWSE ISSUES
  March 2014 Sound & Video Contractor Cover February 2014 Sound & Video Contractor Cover January 2014 Sound & Video Contractor Cover December 2013 Sound & Video Contractor Cover November 2013 Sound & Video Contractor Cover October 2013 Sound & Video Contractor Cover  
March 2014 February 2014 January 2014 December 2013 November 2013 October 2013