bitrate problems

VEGAS Pro

bitrate problems

Posted by Bryce Kelley on January 31, 2011 at 2:03 am

Hi,
I’m using Sony Vegas and DVD Architect.
I used the bitrate calculator at videohelp.com to figure out how to fit multiple titles onto one 4.7GB DVD-R.
But DVD architect shows that my disc space used is 5.1GB.
I understand that a bitrate calculator only gives an ‘estimated’ value. But would it overshoot by this much, or is there something about this process that I’m not understanding?

I have 4 titles, one introduction, and one menu background (video).
All of these were calculated into the equation when I used bitrate calculator.
The length of each video is:

introduction: 00:00:30
menu background: 00:00:59
Title One: 00:29:12)
Title Two: 00:22:53
Title Three: 00:23:57
Title Four: 00:27:06

The combined duration is 01:44:37.

I rendered the video and audio separately.
Here are the settings I used:

Video:

MPEG-2
VBR
max: 8,000,000 bps
average: 5,560,320 bps
minimum: 2,000,000 bps

Audio:

AC3
348 Kbps
48,000 Hz
24 Bit, Stereo

When I used the bitrate calculator, I changed the ISO from 25 to 30 since in the help section, it was suggested to increase it for menus etc. Not that I’m making any complex menus, but I do plan to have the basic title selection and chapter selection options, so I increased the value just to be on the safe side.

Any suggestions before I return to the ol’ drawing board? How should I render these files in Vegas to make them fit onto a DVD?
I don’t want to change my audio settings and I don’t want to use DVD shrink or any other method that will decrease the quality any more than I need to. Basically, I think I just need to know how to correctly calculate my bitrates.
But if you’ve noticed anything else I may be doing wrong, please point me in the right direction.

B

Bryce Kelley replied 15 years, 7 months ago 2 Members · 4 Replies
4 Replies

Bryce Kelley
January 31, 2011 at 2:47 am

I failed to also mention this info, just in case you need it:

Video: 29.970 fps, 720×480 Lower field first, YUV, 6 Mbps
Pixel Aspect Ratio: 0.909
Mike Kujbida
January 31, 2011 at 3:24 am

DVDA has a long history of incorrectly reporting file sizes.
If you know your total file size is under the limit (and I;m sure it is), then ignore the warning and proceed as usual.
My guess is that DVDA won’t give you any more grief.
Bryce Kelley
January 31, 2011 at 5:30 am

Thanks Mike! I’ll give it a try.
Bryce Kelley
February 1, 2011 at 6:18 pm

Well, I found that it was in fact too big to fit on the dvd.

But then I discovered it was only because I didn’t change the kilobit size in the bitrate calculator to 1 kilobit = 1024.

To anyone reading this post, Sony Vegas defines 1 kilobit as 1024, while some other rendering programs define it as 1000. So be sure to specify this when you’re using a bitrate calculator or you will end up with the same problem.

Now I know! …and knowing is half the battle (as they used to say on the GI Joe PSA’s in the 80s) 🙂

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