Frame size and bit rate question.

[rbautch]

I've been converting DivX AVI movies to mpegs using TMpgenc, trying to control the file sizes to get a couple movies on a DVD+R. I usually use the SVCD template in Tmpgenc, then set the Audio rate to 48,000. Or, I use the DVD template and reduce the encoding bit rate to about 3,000 kbps. I have a few questions on how I could do this better:

1) Which is the better way to control file size with minimum loss of video quality - frame size reduction or bit rate reduction?

2) If the frame size of the original AVIs vary widely, am I reducing video quality or wasting space by encoding at SVCD or DVD frame sizes?

3) Are there any other frame sizes I can use that are DVD compliant?

[FOO]

I mostly capture from TV and I have
noticed that a real long video works better if
you reduce to half D1 to make it fit instead of
reducing the bit rate at full D1

In other words 352 x 480 @ 2000Kbps looks OK
but 720 x 480 at 2000 kbps looks terrible