forums.ps2dev.org

taz030485 · Joined: 27 May 2004 Posts: 27

With EEUG's developments with SMS and the newly implemented AC3 sound, I was wandering if it is possible to output the AC3 sound to the optical port (SPDIF) for decoding on an external suround system?

I searched the net for a few hours earlier to learn (or atempt to in the time) as much about the various components involved and am not 100% sure how everything works. I know that there is very little documentation on the SPU2 (excluding dev kits). I found a this thread http://forums.ps2dev.org/viewtopic.php?t=1115, mainly refering to the second last post. I found a 236 page specification on AC3 (Don't know how much help that will be). I'm not sure how all the formats interact on the various components, PCM, AC3, PS2, SPDIF, 'Sound System'. If it helps my system is a Yamaha TSS-1.

If anyone could shed some light on the feasability of this? ie: not possible, tricky, possible, would take some work or 'done', along with reasons, references, etc. I shall keep researching into the various components (non-PS2) and see how they work and possibly report my findings. There would be a fair few people out there with sound systems and with AC3 audio becoming more widly used (not just on DVDs) why not take full advanagte of it.

Note: I may not know any coding or be able to help develop anything, but I am fairly knowledgeable on IT, tech, etc and have been watching PS2 homebrew for just over one and a half years so there's no need to dumb anything down ;)

Regards Andrew (aka Taz030485)

J.F. · Joined: 22 Feb 2004 Posts: 2906

As far as I understand it, when you activate SPDIF on the PS2, the SPU2 simply diverts the raw data coming from the stereo pcm audio stream to the SPDIF connector. The SPDIF data stream supports raw PCM stereo 16bit samples, raw AC3 data, and raw DTS data. I have the SPDIF activated on my PS2, and sound from current projects like SMS play across it just fine. I should be able to modify the code to just dump the AC3 data in packets to the sound out and my digital deck should decode it. I've been swamped for time, but I'll update SMS and try that, probably by the weekend.

taz030485 · Joined: 27 May 2004 Posts: 27

I have it enabled on mine also. If you do try it and it works pass it on to EEUG and see what he thinks.

J.F. · Joined: 22 Feb 2004 Posts: 2906

I will. I'd love nothing better than to have support for SPDIF out. Then some folks wouldn't need to worry about decoding AC3 or DTS, which would allow more time for video decoding. :)

Not to mention, digital sounds MUCH better than decoding and playing out the analog lines. Just the difference in playing a CD on the PS2 via SPDIF and analog is amazing.

taz030485 · Joined: 27 May 2004 Posts: 27

J.F. · Joined: 22 Feb 2004 Posts: 2906

Sorry, been too busy to try, but I did at least update the PS2 stuff to the latest in the repository. Maybe this weekend...

taz030485 · Joined: 27 May 2004 Posts: 27

taz030485 · Joined: 27 May 2004 Posts: 27

J.F. · Joined: 22 Feb 2004 Posts: 2906

Uh, sorry. The week before last, I accidentally erased my system. :O I'm just now getting back to where I was. Sh-t happens. :)

I'm currently checking out a fresh copy of the svn. After that, I need to setup the toolchain again.

taz030485 · Joined: 27 May 2004 Posts: 27

DAMN, I hate it when that happens :@

Hope u didn't loose anything valuable/irreplacable.

Also I'm having trouble setting up the toolchain on my system, I posted in a thread about it but haven't got an answer yet.