DVI & software implications

Posted by: Arun Mehan on 08 December 2004

With the increasing availability of DVI on DVD players, does this mean that the software will change? I realize that most players can output 540p via progressive component, but if we want native 720p or 1080i will the software have to change also? Will our favourite DVD titles be re-released with higher resolutions? Is this similar to a SACD versus CD?

So many questions and worries, please help.
Posted on: 08 December 2004 by Frank Abela
There isn't a simple answer to this. If you 'want' native 720 or 1080, you can either use an upscaler or you can put it on the disc.

In fact the push to higher definition is not due to DVI, but to HDTV which allows you to have a higher definition picture than is available from standard PAL and NTSC.

There are two competing formats for high definition discs (of course Frown ). These are Blu-Ray and HD-DVD. Both formats have enough storage capacity to be able to store high definition films on the disc. However, 'high definition' hasn't been particularly well defined since it stipulates only 'above 720p'.

So yes, it's similar to DVD-A vs SACD. And if it's really similar, then the question is whether the vast buying public is prepared to upgrade to Blu-Ray or HD-DVD given that they adore their DVD-V quality already.

All opinions are my own and do not reflect the opinion of any organisations I work for, except where this is stated explicitly.
Posted on: 09 December 2004 by Arun Mehan
Thanks Frank, as usual you are a fountain of information. I was just too lazy to do my research this time Smile

I knew HD was pushing the new formats, but that was the extent of my knowledge. HD broadcasting is in its infancy in North America but some of the results are astonishing. I'm not a football fan but for some reason, the HD football broadcasts have the best picture and I can't believe the difference from 540p DVD.

I guess we'll have to wait and see (as usual) regarding the future of the Blu-Ray and HD-DVD formats. I guess it's safe to buy some gift sets this Christmas for myself then!
Posted on: 09 December 2004 by David Dever
Many original film (and television) titles digitized for intended DVD release (or for broadcast) were encoded at a resolution well above NTSC or PAL/SECAM specs...some of these already exist as Windows Media 9 hi-def releases at 720p or higher.

Most of the work on the transfer side is spent on setting the encoding breakpoints (keyframes); actual resolution and bitrate can then be arbitrarily adjusted to suit the release format.

Many of the people I know who work in video content creation or assembly are ALREADY working at 720p for DVD menus, let alone 1080p. Therefore, I'd expect a whole slew of re-re-releases as soon as computer drives for either or both hi-def disc formats hit the streets.
Posted on: 09 December 2004 by Jay
Originally posted by David Dever:
Most of the work on the transfer side is spent on setting the encoding breakpoints (keyframes); actual resolution and bitrate can then be arbitrarily adjusted to suit the release format.

Hi David

I understood everything but this sentence. What are keyframes?

Thx Jay
Posted on: 09 December 2004 by David Dever
Certain sections of video require higher bit rates to deliver a decent picture without compression artifacts. MPEG-2 encoding, for example, typically uses 8x8 pixel subframes and i-frames, among other things. (When you scratch a DVD, you can see this super-pixelization at work...)

These keyframes can be arbitrarily set closer, or to happen at specific intervals, so that more data storage (and bit transfer rate) is allocated to describe the DIFFERENCES between subframes during complicated scenes (e.g., closeup action).

It takes an experienced operator / engineer to make these decisions during the video mastering process (think of it as "bit budgeting"), though the quality of software-based encoders (which make the decisions heuristically, without pre-encoding) has definitely gotten better in the last couple years.

[This message was edited by David Dever on Fri 10 December 2004 at 1:31.]
Posted on: 10 December 2004 by Jay
Fantastic. Thank you very much.