WMC suddenly videos play without audio

[Seasmass]

Brief HTPC component list:

• OS - Windows 7 x64 Professional
  Tuner - Ceton InfinitiTV 4
  GPU - Sapphire Radeon HD 6570 1GB DDR3 HDMI/DVI-D/VGA PCI-Express Graphics Card
  AV Receiver - Marantz NR1601 Audio Video Receiver (connected via HDMI from the GPU)
  5.1 Speaker system

Everything was running smoothly until yesterday when WMC stopped outputting audio while I watch video files.

The issue exists with live TV, wtv, and ts files. However, avi, wmv, mp4 files play with audio fine. I haven't done extensive testing on various file types and audio encodings (too newbie). I've tested .wtv files that are Dolby Digital and stereo. Both fail to output audio. WMP and WMC have the same issue.

VLC Player can play all of my files just fine. VLC doesn't seem to output Dolby Digital though. WMC on other computers can play the files fine.

Here are the fixes I attempted:

• - I've checked the Volume Mixer. Volume is maxed out for WMC. Within the Volume Mixer, the green indicator next to the volume scale never appears while WMC is playing the files. Its as though WMC simply isn't attempting to output sound.
  - I checked my Sound devices in the Control Panel. The Radeon card is set properly as default. Everything looks fine here.
  - I attempted the speaker setup within WMC. It fails to output sound, and provides no quality advice on what to do.
  - I attempted to uninstall/reinstall WMC and WMP. It did not fix the issue.
  - I ran Microsoft's Fix It utility for audio problems (http://windows.microsoft.com/en-us/wind ... dia-center). It does not detect any issues.
  - I installed Shark007 w/ 64 bit components. I reset all the settings and then used Shark007's suggested settings. This did not fix the issue.
  - I restored the system back to a restore point from 3 days ago. This did not fix the issue.

I'm out of ideas on what to do. I feel like the root cause has to be something simple that I am missing.

[epayson85]

Uninstall any extra codecs you have installed including shark007. Reboot the computer then go to your audio devices and disable everything except the radeon HDMI. I have had this happen before where media center chooses to use a different device. The other files work because they aren't using the Microsoft codecs. Once youre back up and running only install shark007.

[Shark007]

I would suggest checking 2 things...
in Control Panel | Sound, under your active device, [Configure] a proper speaker count.
and under the [Properties] | Advanced section of your active device, see that the 2 Exclusive mode boxes are checked.

[Seasmass]

Thanks epayson85 and Shark007.

I attempted Shark's suggestion first because of its simplicity. I configured the 5.1 speaker system (all tones played properly). Both exclusive mode boxes were already check. I retested and the issue still exists.

I then attempted epayson85 suggestion exactly as described, but unfortunately the issue still exists.

Thanks for any other thoughts.

[Seasmass]

Well... I'm frustrated (and embarrassed). The issue was caused when someone hit buttons on the receiver remote which they shouldn't have. There was a problem with at least two settings.. decode mode and something called "a/b speaker". The PC wasn't the problem clearly, and I wasted a lot of time on the assumption that it was the problem.

Oh well.... Thanks for your help guys.

[Shark007]

good to hear you've solve it and thanks for the follow up!