Record 5.1 on computer through digital input

[benswis]

Short intro:

I recently asked whether there is a sound card that can record 5.1 surround audio through optical SPDIF input and was told that the sound card is irrelevant here because I'll record what I transmit and it would be up to the software to decode the info
(http://www.tomshardware.co.uk/forum/page-267526_10_0.html)

However,

I've contacted several sound card companies (Creative and M-Audio and I forget) and asked them whether the <insert sound card with digital input> can record 5.1 audio and was told that it could only record stereo. When I asked for sound cards that can do this I basically got the same reply.

So...what do you think, who's in the right? Can it be done?

 

[gamerk316]

Of course it can be done...with a caviat:

The digital input port (SPDIF) can only carry 5.1 by means of Encoded Dolby Digital or DTS. This can cause one of two things to happen:

1: You can record the input just fine, but its in an encoded format
2: You can't record until the signal if first decoded (meaning you're recording software would need the relevent decoders).

I'm not sure which is the case, although I would assume 2 is the case in this circumstance...

 

[benswis]

Thanks gamerk316, you're right, 2 is the case

I found a good explanation in another forum
http://www.avsforum.com/avs-vb/showthread.php?p=15846010#post15846010

 

[gamerk316]

Looks like you need to find some software that will convert a .DD (a Dolby Digital encoded file) into a more common (.mp3) format.

So basically:

Encoded Audio -> Capture Program -> .DD filetype -> Converter Program -> .mp3/wav

Some sound cards still have decoders though; I know the Audigy 2 line has decoders, and THINK the Elite Pro has them as well...Then its just a matter of capturing the audio stream.