can't compress file any more?

[kita]

hi, i'm trying to fit 12 television episodes onto a single DVD disc. At first, I started out with some standard HQ settings: 1.85 Mbps video, 48khz-224 audio. That had the file size at about 680 MB per ep, but that's not enough to fit them all in.

I figured I'd sacrifice quality if I could just get them all in. So I started dropping my settings to about 1.2 Mbps video and 48k 192 audio. That got it down to 450 MB. But now it's stuck!

I tried all the way down to 0.5 Mbps, 128 audio, but it still won't go below 450 MB. I always thought file size was directly related to bitrate. It's not?

I did 1.2 Mbps vid / 192 aud
0.95 Mbps vid / 160 aud
and finally 0.5 Mbps vid / 128 aud

all were about 450 MB!

[andkiich]

It almost sounds like the program you are using has set up some kind of arbitrary floor for how low it will go. There should be a difference, but this is the best explanation that I can come up with.

[kita]

using TMPGEnc Plus 2.5

I used VirtualDub to check the file info and according to that the files have the bitrates I set them to...