[paddington]

If you have WinDVD, you can start playing one of the bigger VOB files (not the menu or something) and right click on the video image while it plays, choose SETUP... and then the INFORMATION tab. The audio section will show something like this:

Audio:
Hardware:
Audio Device: directsound
S/PDIF: Present
Number of speakers: 2
Stream:
Type: Dolby Digital (AC3)
Bitrate: 448 Kbps
Number of main channels: 2
LFE Channel: None
Sampling Frequency: 48khz
Bits Per Sample: 16
Output:
Sample Rate: 48 KHz
Bits per Sample: 16



The 2 main channels indicates this is probably stereo - however it only means they ENCODED it with 2 separate channels. It is still possible that the source audio is mono and just copied to both channels equally,.

In other words, you can't be positive, but you can check for the number of main channels and then listen to see if you hear different things in each channel to verify.