capturing surround audio?

[crimazine]

I know this is a video capturing group but can anyone here tell me anything about capturing surround audio via an optical cable? I'd like to capture Dolby Digital Audio from a Laserdisc system to hd for svcd/dvd.

- Crimazine

[EricBall]

Note: although LDs often have DD encoded, the digital output from most LD players was RF modulated over a coaxial connection; while DVD players use either optical connectors and/or coaxial connectors which are _not_ RF modulated. There may be some LD players with optical connectors, but they would have to be fairly recent.

In any case, the "easiest" way might be to connect the LD player to a compatible DD decoder (e.g. RF coaxial connector), and then sample from the 5+1 preamp outputs. This wouldn't give you the DD bitstream, and you will probably have to make multiple passes, but you will get all the channels.

The alternative would be to find an LD player with an optical output and a soundcard with an optical input that you can pull the DD bitstream from directly.

[crimazine]

This is the LaserDisc system im working with:

http://www.laserdiscarchive.co.uk/DVL-909.htm

It looks to have Optical Out and we were planning on using this. Also recently purchased a soundcard WITH Optical Input port. Now all I need to figure out is how to CAPTURE this DD Signal? ZYron suggested capturing it in 48000khz RAW PCM and just saving it as a ac3. I've yet to try out this method but would welcome any other ideas. Thanks for responding EricBall.

- crimazine

[StephLG]

Hi,

I may be wrong, but if you want to capture a DD 5.1 (AC3) stream out of a LD, you must use both the digital out (coax or opt) AND the AC3-RF out of your player. You have to combine those two streams with an AC-RF decoder (included in some Home theatre preamp) and take the result, which can be either 5+1 channels or a recombined single AC3 digital stream (from your preamp out, for instance).

If you want to capture the 5+1 channels separatly, you have to follow EricBall 'Easiest way'.

If you want to capture the recombined digital stream, you have to... I don't know :( I'm also in the process of doing this for my Star Wars SE LDs, and I also have a sound card with optical digital in and a preamp with AC3-RF in and optical digital out, but I don't know how to capture a 48KHz raw audio stream (with what software?) and I don't know if the resulting file will be correctly interpreted if you just rename it (I doubt).

Any feedback from your experiments would be welcome.

[ReinerSchweinlin]

Hey guys.

ANy luck in capturing Digital Audio (DD) from LD? Is there an external RF-De-Modulator available? This way, one could use the SP/DIF input, I guess, or am I wrong?

Greetings
Reiner

[dilly]

hehe, I'd assume by the deadness of the conversation that he either

a] followed an above proposed solution
b] gave up

Or else he would have kept it going past July, probably :)

[ReinerSchweinlin]

Thanx for this helpful reply :rolleyes:

[ohliuv]

there was a thread on this here (http://forum.doom9.org/showthread.php?s=&threadid=42568)
Hope it helps

[ReinerSchweinlin]

Thanx!! Great, seems to work somehow. All I now need is a RF_Demodulator. I looked at ebay, but can´t find any here in Germany. Maybe I have more luck in the UK.

Greetings
Reiner