Mac Newbie is Puzzled about Aspect Ratio and Image Size

[Remillard]

Hello,

Well I'm new to Mac-dom. We bought my wife a G4 iMac and it's been pretty nice so far. We got the one with the SuperDrive and then bought Toast 6 with the idea that we could put video onto DVD eventually. I've coasterized one DVD (burned about a quarter inch and then said "Drive reports error" so I haven't quite figured out what's wrong there) and so I've switched to SVCD as the discs if I blow it, aren't as expensive.

Anyhow, on to the questions. I have an AVI video in DivX format that I would like to put onto either SVCD, and then eventually DVD. The resolution is 640x480. Ergo, the aspect ratio is 4:3, so as far as I can tell, this is perfect for the TV (if I'm understanding things correctly).

I've put this onto SVCD, and it worked alright, except for the fact that it seems to have focused on the center of the image. There is a little cut off at the top, bottom, right, and left. It's almost like there's a viewport on the main image. The shape looks okay, so it's not compressing it vertically or horizontally to make it fit. I think the aspect ratio is correct, but is there an image size that I need to worry about?

Now the application for the encoding/burning is Toast 6. It seems to use QuickTime for all its converting needs. I have not found any control anywhere that says "This is for a regular TV, make it that size, without cutting anything off." So I think I might have to migrate to something that gives me more control, but I don't know what that might be.

Does anyone know what I'm doing wrong here with the video getting cut off at the margins? Do I need to get something to convert aspect ratio? Do I need to get something that sets some sort of correct image size?

Alright, thanks for listening. Here's hoping someone out there can help me out a bit. I did do forum searches on aspect ratio and so forth, but they all seemed much more esoteric than what I was looking for.

Regards,
Remillard

[havema-1]

You can calculate the correct scaling, cropping and padding values using the info on this site:

http://www.uwasa.fi/~f76998/video/conversion/

Notice that on a TV screen there is overscanning -- i.e. the TV crops several % of the image's sides. This is normal and it varies somewhat on different TVs so you have to position your titles and other material in the video to the "action- and title-safe" areas so they won't be cropped by overscanning.