Getting 5 or 6 channel sound working with Media Center Edition 2005 and S/PDIF
When I first got my media centre working I was really pleased to have stereo, but after a few weeks I decided to look at getting my DVD's playing in 5-channel sound. Boy! Was I in for some hassle. But, the good news - all the software and relevant hardware already supports 5 or 6-channel operation out of the box, you just need to be prepared to experiment. I gave myself the highest challenge because I wanted to go directly to a digital connection between the Media Center PC and the amplifier using an S/PDIF connection, mainly because this is an excellent connection medium and is actually simpler than the 5 cables that you would need to do it using analogue.
So, to try to help others along this same path, here are some tips.
1. You will need to address settings in the following software and hardware areas:
Motherboard sound hardware settings (e.g. enabling S/PDIF out and mode)
Motherboard S/PDIF output to amplifier S/PDIF input (the cable)
Amplifier settings (e.g. correct input and mode)
MPEG decoder audio settings (to enable multi-channel and S/PDIF out)
There is no configuration of MCE for this at all, it is totally down to the above components.
So, you need a debugging strategy so that you can verify that all is working along this chain backwards from the speakers. There are two main ways of debugging this setup (or three if you count playing a DVD in MCE which will never work first time!):
Use a DVD player with S/PDIF output to feed your amplifier.
Use the motherboard audio test utilities.
If you can do it, '1' is great. Setup your multi-channel amplifier and speakers and then pipe an S/PDIF signal into the amp from a DVD player and get the sound working up to the digital input of the amplifier. If you don't have a DVD player with S/PDIF out, use the PC's audio utilities. Most come with test software that switches the motherboard audio into 5 or 6-channel modes and outputs test signals that walk around the speakers. Get this working next. If you cant succeed with these utilities, forget going into MCE yet.
When you have got the motherboard audio outputting 5 or 6-channel test tones, go into MCE and play a DVD (or a ripped DVD from disk, both should retain the multi-channel sound track). Use a recent film and check that the DVD boasts 'Dolby digital 5.1' or similar and is not an old stereo film. You may now be lucky and immediately hear sound around you but I didn't. The next step is to find the settings for your MPEG decoder that is rendering the video and audio from the file stream. They make this REALLY hard. I have the NVIDIA PureVideo decoder and the only way that I have found to get into its settings is to play the appropriate video, switch away to the PC desktop WITHOUT STOPPING THE VIDEO and then to double click a tiny tray icon labelled 'NVIDIA DECODER'. This opens the property page for the decoder and Lo! there is an 'Enable S/PDIF' check box there. More usefully still, there is a summary of the audio stream mode too, allowing you to confirm that the decoder is seeing either MPEG (stereo) or Dolby Digital etc. (The reason that you must not stop the video is that there is only an instance of the decoder whilst video is playing - there is no decoder and no tray icon without moving video - worse, if you leave the property page open and stop the video, it all looks good and allows changes, they simply dont do anything, nor do they 'connect' to a subsequent instance of the decoder). I'm afraid you're on your own with the decoder if you are using Sonic or InterVideo etc.
Have fun. Check out the pictures below of my settings that I fiddled with to get my system working. I apologise for the picture quality!
Below - NVIDIA decoder properties showing the S/PDIF enabled and playing an MPEG mode audio.
Below - the motherboard audio utility showing the digital output mode.
Below - the motherboard audio utility showing speaker modes and tests.
The next two photos show how the amplifier switches automatically between a simulated stereo to 5-channel mode (PLII movie) and the actual Dolby Digital mode when the correct digital signal arrives.
Below - the NVIDIA decoder displaying its audio modes whilst playing various file formats.
