What is VLC doing when downmixing 7.1 or 5.1 to stereo?

[bigkid]

Hi all.

I have used VLC on a windows HTPC for years but I have always set VLC to pass through the digital audio via HDMI to a Denon processor. We have just moved home and the new place is not really set up for the 5.1 or 7.1 experience. So we are just going with 2.1, losing the Denon in the process. My main speakers are GoldenEar Triton Ones which have built-in subs that are more than adequate for our needs. We intend having VLC play a range of video files from a NAS with varying audio content stereo, DD, DD+ TrueHD, DTS and DTS Master.

With 2.1 I had planned plan on passing the audio (and video) from VLC to my Oppo BDP-103 blu-ray player for processing/downmixing but that is not working out so well for a number of reasons not relevant to this post. So I am now thinking of using VLC to downmix and pass digital stereo via usb to my Chord DAC (to get the D-A conversion out of the noisy PC environment). My query is what does VLC do when downmixing? Is the audio from the surrounds and rears aggregated with the audio for left and right? What about sub audio, is it included in the mix and would be passed through to the DAC? And what does VLC do with DTS Master in these circumstances?

Appreciate your advice.

Regards,

Allan