Understanding DVD Encoding

[Suhit Gupta]

<div class='os_post_top_link'><a href='http://www.emedialive.com/Articles/ReadArticle.aspx?ArticleID=8309&PageNum=1' target='_blank'>http://www.emedialive.com/Articles/ReadArticle.aspx?ArticleID=8309&PageNum=1</a><br /><br /></div>"Part of what makes today's consumer-friendly DVD authoring tools so accessible is their success in shielding users from encoding and other techie tasks. But while ignorance may be bliss, aspiring DVD authors can't do competent commercial work without a working understanding of the encoding process. What's really happening behind the scenes, and what do you need to know about encoding to produce top-quality results?"<br /><br />Colleen Kelly of emedialive.com has a point in that entry level DVD authoring tools allow beginners to create DVDs quite trivially. However, these tools abstract away most of the technical details and understanding from the user, perhaps hurting those beginners that aspire to become professionals in the field because they never learn the true software process that is involved. Therefore, she writes this article explaining some of the ins-and-outs of these pieces of software, and how DVD encoding and compression works.

[Philip Colmer]

An interesting article but the content wasn't quite what I expected. I thought that it was going to deal more with the structure of a DVD itself (i.e. menus, subtitles, etc) - the things that entry-level tools really don't give you much choice over.

Whilst the article offers some interesting thoughts (e.g. always use VBR instead of CBR when encoding the video), some of the justification doesn't make sense. For example, on page 2 it talks about how

"... entry level tools will do their best to push users into the 6-9Mbps range for home video encoding. Hollywood movies, by contrast, have an average bit rate of around 3-5Mbps."
It then says that using VBR allows

"the encoder to produce difficult-to-compress sequences like football scenes at higher data rates, say 5.5Mbps, which translates to higher quality video"
But that is still below the encoding range that the entry level tool would aim for! So what I don't understand is what is so wrong with using that higher data rate?

If the point they are making is that the higher data rate consumes more space so you are then restricted to how much you can fit on the disc, then OK, I get that point. However, I've just finished a three year home video project and the total content runs to 40 minutes. I don't think I'm going to start worrying about needing to use VBR in order to reduce the amount of space taken up if I can whack the data rate up to 9MB and get best quality possible. It just doesn't make sense to me.

I do agree, though, that if you are tight for space and need to get more onto the disc, VBR is your answer.

However, as with most product ranges available out in the big bad world, there is a place for entry-level tools and a place for professional tools. The entry-level tools allow the user to get an end result without having to worry about the additional complexity that is going on behind the scenes. It seems to me that Colleen is knocking those products a bit too harshly. I got a bit confused as to who she is aiming this article at!

I also found it mildly amusing that whilst she refers to products from companies like Sony & Pinnacle, she didn't make any reference to Adobe - who managed to place an advert within the text on every page :)

--Philip