Windows – Realtek HD audio 5.1 optical input (from Xbox 360)

inputspdifwindows 7xbox360

I'm trying to connect up my Xbox 360 digital audio to my 5.1 speakers via my PC (my LCD has dual input, DVI for the PC, D-SUB for the Xbox).

The motherboard (Abit AB9 QuadGT) has a Realtek ALC888 chipset and I have a 5.1 speaker system connected via 3 x 3.5mm jacks (FR/FL, RR/RL, C/LFE) and I get full 5.1 output from the PC.

I have connected the optical audio cable from the Xbox to the optical in on the motherboard's backplate.

With the Xbox in Digital Stereo mode I get 2 channel audio from the Xbox, through the PC, to the speakers.

With the Xbox in Dolby Digital 5.1 mode I get no sound at all.

I have the latest Realtek drivers installed in Win 7 32-bit.

Questions:

  1. Is it possible to use the full 5.1 DD from the Xbox?

  2. If so, am I missing some option(s) in the Realtek setup?

  3. Do I need some other piece of software to do this? (AC3Filter or FFDShow perhaps)

Best Answer

To answer your questions in order:

  1. Yes, it is. The Xbox 360 supports Dolby Digital 5.1
  2. As long as you have it set to use the digital optical input rather than the sounds on your PC, that's all the setting you need to do
  3. Here is where your problem is. See below:

The problem seems to be that Dolby Digital signals need to be decoded for them to be played. This is no problem for any receivers that support Dolby Digital, because they have built in decoders.

Your PC (or more specifically, your motherboard/sound card), does not have a built in decoder or it would be working. I imagine most 'high end' sound cards have built in decoders.

You do need extra software for this to work.

Looks like realtek claims to have software enabled decoding of Dolby Digital, so you can try that, or,

ffdshow claims to be able to decode 5.1 Dolby Digital and it is FOSS, so you should be good to go with that.

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