how many megs can I fit on DVD video?

[emazur]

I have 3 mpegs that in total are 4.27 meg, I load them into tsunami DVD Author and it's reported the size is too big (4479/4438 MB). I didn't add any extra music or video menu or crap like that. I realize that it takes some padding to make DVD compliant vobs but 200 meg is excessive, is it not? So i was wondering what other options (freeware/shareware if possible) that I have to fit these 3 mpegs onto a DVD movie. I can combine them into 1 mpeg if need be since they're all the same res/bitrate

[Matthew]

You should always do these calcs in bytes, if nothing else to avoid the 1024/1000 conversion issues.

Anyway just taking something I have on my HD atm, the m2v+ac3 is 4,529,865,448 in total. From memory when authored that should be undersized by about 50 MB, so overhead is around 120 MB. The video is only 103 mins though...overhead increases not only with filesize but also running time. If the video were 360 mins it would likely be oversized. So if these are 3 full movies encoded at a low bitrate then expect some fat overhead.

Combining the mpegs shouldn't make a difference to the overhead, and I don't think that using another authoring app will result in reduced overhead.

[emazur]

Hmm, that's too bad, though I suppose I can cut out the intro and/or credits of some of these captures. Is there a fairly reliable way to calculate overhead? FYI, in this case there are 3 clips of the following lengths (all 352x480 mpeg2 3000kbps video, 224 kbps mp2 audio):
1:33:18
1:34:20
1:25:34

[Matthew]

Fit2Disc, a payware app from author(s) of FitCd is supposed to have a really good bitrate calculator but I've never used it. DoItFast4U also has a (fairly crude) bitrate calculator.

I've done my own tests with video and found that it is quite hard to predict overhead. It varies with bitrate, and if you are doing VBR the average bitrate isn't a great figure to use when estimating overhead because how that bitrate is distributed affects overhead.

For audio the overhead seems to be about 1.6 percent for AC3 and 7.0 percent for mp2. i.e. if you have vobs with just video and then add audio, the vobs will increase by (audiofilesize*1.07) if you are using mp2.