No DD on Live TV, but DD on DVDs

BUMP

I am having very similar issues and am struggling to get this resolved.

I can get my Chaintech 710 (using VIA chipset drivers) to pass-through the DD/DTS signal if I am watching a DVD. The 710 is connected to my Onkyo 603x AVR using a toslink optical connection. However, I cannot get the DD to passthrough from OTA HDTV programming. I have tried Media Center, Sage 6, and BeyondTV running on MCE 2005. (I am actually only trying to get MC to work but tried the others only to troubleshoot.) I did the speaker setup in MC and set it to TOSLINK. (shoulud there be an S/PDIF option?) The audio 'test' will only output audio from the front three speakers (L, R, C) -- probably because it is not encoded in DD or DTS? After the speaker setup is complete, it automatically runs the nVidia DVD audio setup which actually gives me the option for S/PDIF passthrough (no downsampling.) It seems to me that there should be an option to select 'S/PDIF passthrough' in the 'TV/Audio' setup menu. BTW, I am using the nVidia PureVideo decoders, hence the reason I get the nVidia options for DVD audio setup.

What am I doing wrong? It seems as though I have tinkered almost every possible option but have yet to see the DD from the OTA HDTV passed through.

Any help would be appreciated,
Thanks!

I had a similar problem several months back. Seemed when I installed a newer version of MediaPortal over the old copy, it reset some of the settings back to their original defaults... including audio on the MPA audio codec back to "stereo" instead of "3+2" (or "5.1," I forget how it's actually named).

I wouldn't have thought that would make a difference with AC3 sound, but as soon as I flipped that setting back to 3+2, everything was 5.1 again.

Well I solved the issue that was plaguing me in MC with OTA HDTV. Being a newbie to much of the audio issues involved with codecs and filters and such, I thought I would post this solution as a service to all of my fellow newbies.

The solution was actually quite simple -- which is what I had suspected to begin with but just couldn't get the straight answer even after much searching. Basically, I knew something was getting 'confused' within my audio filters but I had no clue how to even figure out where to set these up.

All I had to do was download DSFMgr from Softella's website and use this program to set which filter I wanted to get highest priority in the list of DirectShow filters. I found the nVidia audio filter in the list, double-clicked it and gave it the highest possible priority. I also checked its settings to make sure that S/PDIF passthrough was enabled (it already was because this filter was what I used for DVD's) As soon as I closed MC and reopened the HD channel I was watching, the DD 5.1 audio came through in all of its glory.

Like I said, this is most likely a very elementary procedure for many of you but, nonetheless, an obviously very important step in getting a HD HTPC set up correctly. It has probably been outlined 13598137515890 times in the forums but I couldn't find this in my efforts.

Hope it helps!