Converting Quicktime Movie to MPEG-2

[Criggles]

I need to be able to encode a Quicktime I have at 720x480 to an MPEG-2 of the same size. However, no matter what I do, I always end up with a taller m2v file at the end of the encode. It consistently comes out at 720x540. If Letterboxing is checked in the options, the video is the correct aspect ratio but has black bars. If not, the video is stretched. Neither of these options is satisfactory. Why is this and what can I do to fix it?

[Case]

MPEG-1/MPEG-2/DV stores movie information using non-square pixels. On top of that, they use the exact same size (720x480) for 4:3 and 16:9 material, by stretching as needed on playback.
What's worse, QuickTime Player shows the movie size 'corrected' for square pixels, i.e. the measurements of the video window in View>Actual Size. And of course QuickTime movies can have a custom aspect ratio to any size you like, without altering the video content.

In order to answer your question, it would be helpful to know how you got those size numbers (which app), what kind of video stream is in the QuickTime file, and the desired aspect ratio (4:3, 16:9). And last but not least, what app are you using for the conversion?

[Criggles]

I'm starting with a square-pixel 720x480 Animation codec Quicktime movie exported from Flash. I'm using FFmpegX to encode it to MPEG-2. It allows me to select 720x480 as the resolution and it comes out very clean but either letterboxed at 720x540 or stretched. I knew DV used rectangular pixels but it didn't occur to me that MPEG-2 does as well. When I played the MPEG file back through VLC (wouldn't play in QT) it was displaying it at 720x540. I'll probably need to answer the question about aspect ratio when I get back to work on Monday. We're providing it to someone to display on a large ad screen and I'll need to ask them which they prefer.

[Case]

You should create your source file in either 4:3 (720x544) or 16:9 (848x480) if possible, because 720x480 square-pixel is somewhere in between and won't fit the ad screen. To make 720x480 square-pixel fit to frame, you would have to decide to destort, crop, letterbox or pillarbox to make it fit. Better start with the right aspect ratio, imho.

[Criggles]

I think I understand. So by making the source 720x544, it will create a 720x480 rectangular pixel mpeg?

[Case]

Yep
Let us know how it works out.