AC3 decoding

spellinn · Oct 14, 2003, 04:55 PM

From the latest release notes, kX now supports AC/3 decoding on 10k2-based cards. I have some questions :

Is this a purely CPU-based decoder, or does it use any of the DSP/hardware features present on the 10k2? Is this the same method as Creative use in their implementation of AC/3 decoding?

Can it decode AC3 passed to it over the PCI bus (ie from a software DVD player) or AC3 fed into the S/PDIF input? (or both methods?)

Cheers,

Neil

FieroGT · Nov 1, 2003, 09:46 PM

ya, i would also like to know? i got a sblive 5.1, will it work??????? need it bad!

thanx

Rob

Max M. · Nov 1, 2003, 10:19 PM

Lives (10k1 based cards) has following features under kX (today):

Decoding of ac3 from software player - yes
Decoding of ac3 from spdif input - no
Passing ac3 from software player to spdif-out - no
Passing ac3 from spdif-in to spdif-out - yes

Audigy X (10k2 based cards):

Decoding of ac3 from software player - yes
Decoding of ac3 from spdif input - yes
Passing ac3 from software player to spdif-out - yes
Passing ac3 from spdif-in to spdif-out - yes

----
(although some users reported they can't get "Passing ac3 from software player to spdif-out" to work properly)

luterry24 · Nov 22, 2003, 12:06 AM

can tell me how to connect them in dsp??

Max M. · Nov 22, 2003, 10:01 AM

you cannot "connect them in dsp" since none of these functions are performed by dsp... you configure them at main kxmixer page instead.

HunterZ · Nov 23, 2003, 02:32 AM

How do I configure my DVD software's sound settings and the kX Mixer to decode AC3 in software to send to my 4.1 analog speaker setup? The settings are not self-explanatory enough for me, and I'm sure others would like to know too. Thanks.

Lucean · Dec 4, 2003, 05:19 AM

I don't have DVD, but I have an avi with AC3 audio. I guess I need a player with 3 outputs, that would send the front stereo output to Wave 4/5, rear stereo output to Wave 6/7 and center+subwoofer to Wave8/9 ...
I don't know if exists such a player.
But you can test AC3 with http://www.tfm.ro/ac3/download/test_ac3.rar

PITmaster · Dec 4, 2003, 03:22 PM

I do not have any problem with AC3 software decoding with my SBLive but I'm using Vigovsky Alexander's AC3Filter in fact. Every time when I'm playing *.AC3 file or DivX movie with AC3 sound track, the AC3Filter is used by Media Player. Without AC3Filter there's just no AC3 decoding.

How to decode DD sound track with kX software with SBLive and without AC3Filter?

PITmaster

**Eugene Gavrilov** · Dec 4, 2003, 03:41 PM

>> I do not have any problem with AC3 software decoding

in this case I doubt you really need to test the (more or less) unstable kX code, since the decoding is performed in software, too

/E

HunterZ · Dec 5, 2003, 06:34 PM

Since we're on the topic of AC3Filter, is there a reason why the sound is all scratchy if I set it to 24-bit or 32-bit PCM instead of 16-bit? Does kX not support the higher sample sizes or is it a bug in AC3Filter?

**Eugene Gavrilov** · Dec 6, 2003, 05:00 PM

kX doesn't support 24-bit audio for regular output devices (such as 'Wave 0/1') -- but it does support 24/96 for 'Wave HQ' (for audigy2 boards)

(well... the only exception is 24/48 format for audigy1/2 + fxbusx -- search the forum for details)

if you select 24-bit output, windows (in most cases) will automatically convert the audio data into 16/48 or similar 'compatible' format (software resampling)

so, in most cases don't select 24-bit (and 32-bit, of course) -- unless you know what you are doing

(since FXBusX requires some additional wires and the audio format should be 'true 24/48'...)

/Eugene

Orestis · Dec 28, 2003, 11:00 AM

Guys, could you please prioritize a bit the "Passing ac3 from software player to spdif-out" function on live! cards?

...and , when you're done with it, tell the Creative folks how to do it, because they screwed it up (at least under XP)

)

**dj_stick** · Jan 4, 2004, 12:09 AM

no offence to those wanting AC-3 and 3d sound, but the drivers were primarily designed for low latency audio production, only adding on the extra features the card had to offer, so when it comes to priorities, those issues relation to audio production come first

daPyr0x · Jan 27, 2004, 04:52 PM

Okay.....so am I understanding this right?

If I have my Audigy setup with 5.1 Dolby Digital coming in through the S/PDIF inputs on my card, the kX drivers are now able to decode that?

I know the Audigy drivers are, but if the kX drivers are, too....all the better....

Can they? or am I just daydreaming again?

**Eugene Gavrilov** · Jan 27, 2004, 06:07 PM

yes, kx drivers DO decode incoming spdif signal
note that the built-in decoder is not perfect -- you may experience BSODs and reboots

/E