How To Tell CBR vs VBR

I get some MPEG4 downloads that given their size probably should not show macroblocks. I've wondered if there's a way to tell whether the encoder used single pass CBR or multi-pass VBR. I might be missing something, but I can't find anything in GSpot that that says whether a video is CBR or VBR.

How can I tell? If not GSpot what?

Thanks!!

 

Just tried MediaInfo... and I still can't see anything that displays this info.

 

Switch to "Text View" in MediaInfo, you will get more information:
.

.
Some files are not listed with "Variable Bitrate", but instead with a "Bitrate" and "Nominal Bitrate", which indicates VBR.
.

 

Thanks AGAIN cyprusrom!!

So if there's just one listing, say

Bit rate : 1368 Kbps

We know it's a single pass?

Can "nominal" also indicate ABR (Average Bitrate)? I assume that would still take more than one pass.