DVD-MS or AVI --> MPEG2--> DVD: How to predict size,l

[Pcollacchi]

I'm converting video captured from Windows MCE (DVD-MS) and camcorder (DV AVI) to DVD. For the sake of this question, lets assume that quality is not that important.

Source files are usually quite large (> 10Gb) and generally I'd like to get them onto a single DVD.

I've converted one of each type to MPEG2, one, "MPCC" using TMPGenc Express, and the other, "Jaisha", using I forget what, but the actual file system size of both are about the same, 3.5Gb for "Jaisha" and 4.2Gb for "MPCC", yet when I go to author and burn the DVD using Roxio, it tells me that the Jaisha project will be about 3.8Gb and the MPCC project will expand to a whopping 12Gb.

1.) Why basically is Roxio creating DVD's of vastly different size. (parameters for each are shown below)

2.) Conceptually, what video and audio parameters might I tweak during the encoding from DVD-MS or AVI to MPEG2 that will let me predict the final DVD size? For example, I was hacking around with a bit rate calculator that calculates bit rates given a destination output size. I don't understand the intracies, but I get that in order to mash the thing onto a single DVD I can change certain other parameters.

(Ultimately I might wish to choose "quality", or I might choose to cram the thing on a single DVD, but it's a good exercise. And I think I understand frame size -- 720x480 v 350v480, so lets keep the frame size at 720x480. What are the other dimensions that influence MPEG2 file size and DVD file size?)

Thanks fpr helping.


Jaisha

File size: 3.544
Time length: 00:52:21
File Type: Program Stream
Dimensions 720x480
Display Size 720x480
Frame Rate 29.97FPS
VBV_buffer 224KB
Progressive: Prog or Int
Encoding MPEG2
Stream iD xE0
Aspect Ration 4/3
Bit Rate 9.000Mbps
Profile Main/Main
Chroma 4:2:0

Audio
Stream ID xC0
Bit Rate 224Kbps
MPEG layer Layer2
Sampling Rate 48000Hz


MPCC

File size: 4.195Gb
Time length: 02:55:00
File Type: Program Stream
Dimensions 720x480
Display Size 720x480
Frame Rate 29.97FPS
VBV_buffer 224KB
Progressive: Prog or Int
Encoding MPEG2
Stream iD xE0
Aspect Ration 4/3
Bit Rate 8.000Mbps
Profile Main/Main
Chroma 4:2:0

Audio
Stream ID LPCM:0 (xA0)
Bit Rate 16bits
MPEG layer Channels:2
Sampling Rate 48000Hz

[Krispy Kritter]

The first thing to catch my eye is the length (time). One file is 55min, the other is 2 hours and 55min. So that accounts for Roxio creating vastly different file sizes.

The biggest control that you have over the final size, is the bit rate. The highest that it can be by DVD spec is 10Mbps (including the audio). You could try experimenting and see how low that you can get it before you start to notice the picture degrade. Depending on your source material, you should be able to get it down to 2000-5000. The avg DVD movie rate is 5000, currently your files are 8000 and 9000.