The length of video one can fit on a DVD is determined exclusively by the bitrate used to compress the video and audio. As Bob pointed out, the lower the bitrate, the lower the quality of the video. If you have a video with a lot of motion or video noise, then the video quality will fall apart pretty quickly as you reduce the bitrate, if you have a basically static shot of a "talking head", you can use a MUCH lower bitrate without the video taking a significant quality hit.

John

Guys I understand all that. My question was, using the default DVDA 24p widescreen template in Vegas 5 to render my 24p video, what's the max amount of time I can fit on one DVD. It looks like the average bit rate for the default video is 6 Mbps and for ac3 audio is 192 Kbps for a total of around 6.2Mbps. Isn't that roughly 75-80 minutes on a 4.7GB disc allowing some overhead?

Since you understand completely everything that has been said in the previous two responses, then the answer is:

One hour, thirty-eight minutes, twenty-eight seconds.

This is based on the fact that the default 24p Widescreen template uses an average bitrate of 6,000,000 bps. Since you are implying that you don't want to change anything, including the bitrate, this is the amount of time you can get, assuming no fancy menus and assuming no other video or audio on the disc. My bitrate calculator (which I used to answer your question) also assumes a default subpicture size of 207,000 bits and allows 2.7% reserve for the DVD menus and other overhead. It also assumes the audio is encoded using the AC-3 encoder at 192 kbps.

This is an exact answer to your question, exactly as it was asked, assuming you understand everything in the two previous, excellent answers to your question.

While I use my own bitrate calculator, because I added lots of bells and whistles that I wanted, the usual calculator that many people use can be found here:

Bitrate Calculator

It can give you the answer to this, and many other questions.

Finally, there is absolutely zero reason to ever use the default template without changing the bitrate. That, in my opinion, would be folly. Instead, if you have less than 1:38 running time, for heavens sake, INCREASE the bitrate so you get better quality video.

Assuming one non-motion menu and a safety margin of 1% of the total space on the disc, you can get roughly 98 minutes of video on a single-sided 4.7 gig disc using 6mbps video and 192kbps audio.

John

Thanks for the replies.

Johnmeyer - I wasn't trying to be a dickhead; perhaps I could have stated my original question better. I actually find the default Vegas 24p template to be quite acceptable for DVD's. Thanks for your thorough and precise answer to my question. :-)

"While I use my own bitrate calculator, because I added lots of bells and whistles that I wanted, ..."

You aren't going to share?