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Old 08-25-05, 01:42 PM   #1
PrakashP
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Lightbulb @NVIDIA: nv's hw accel openal requests

Hi,

I managed to link a sample openal code to nvopenal and nvalut - and it actually worked . Both libs are included in the NFORCE driver package, but what about Docs and headers? I used the headers from the reference implementation to get it compiled. Then I noticed:

0) Is there a proper SDK availabe? (Docs and headers)? I found something for Windows, but this is pretty useless for me.

1) Your openal implementation is old, as it is 1.0 and it would be nice if you could catch up to current specs - which shouldn't be too much of work. (My sample uses alutLoadWAVFile, which nvalut doesn't provide, so I needed to work-around. )

2) How to configure the thing? I mean does it also read .openalrc? eg. I have a Dolby Pro-Logic receiver connected to my computer, but only via stereo cable. The windows driver makes it possible to encode Dolby Surround, so that I get a "true" rear channel after decoding. I guess this is handled by the APU internally? So it would just be a matter of setting the APU up correctly.

3) Please provide a binary compatible libopenal.so. So we could use the hw accel. nvidia implementation for games like ut200x. There is work done on getting OpenAL into Quake3, as well... (Or could one tell me how to easily bake a libopenal.so out of libnvopenal.a and libnvalut.a?)

4) Did I already ask for the SDK?

Thanx a bunch for giving this native implementation. Just a minimum amount of support packaging would be nice...(Or should it stay a secret that you are packaging both libs w/o mentioning in the README?)

[EDIT:] Ouch, unless you are doing something very clever, it wouldn't be bad debugging your libs using valgrind... (At least with the ref. implementation valgrind doesn't complain of using several uninitialised vars...) Of course I don't know whether this is normal with hw accel.
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Old 08-27-05, 04:44 AM   #2
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Default Re: @NVIDIA: nv's hw accel openal requests

So, I managed to get sound out of quake3 using nvopenal http://www.quakesrc.org/forums/viewt...=5442&start=15, but

a) At least in timedemo mode it seems slower than with reference OpenAL. So is it hw accelerated or not?

b) Sound is less clear with nvopenal. Sounds a bit like when you put fingers into your ears.
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Old 08-27-05, 05:13 AM   #3
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Default Re: @NVIDIA: nv's hw accel openal requests

Note I don't know what nforce board you are using and second I don't know how the nvopenal lib works.

In case of the nforce3 and nforce4 I wouldn't call the sound support a 'real' soundcard. In short the audio data is routed to a small AC97 audio codec useally made by realtek. This codec only supports limited soundformats (useally 44.1/48kHz, 16bit in stereo). If other soundformats are to be used it needs to be converted in software by the cpu. Not sure what sort of audio stuff is inside the nforce3/nforce4 itself. In case of the nforce1/nforce2 it can be paired with the 'Soundstorm' APU which is a sound processor which can do all the audio conversion, hardware mixing, 3d and more.

I wouldn't be surprised if the nvopenal library is software accelerated on nforce3/nforce4 boards while it does some acceleration on soundstorm boards but note this is just a guess.
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Old 08-27-05, 05:30 AM   #4
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Default Re: @NVIDIA: nv's hw accel openal requests

No, of course I use a nforce2 with MCP-T (soundstorm). I know only here I can expect hw acceleration. That's why I am confused about my findings.
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Old 08-27-05, 05:40 AM   #5
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Default Re: @NVIDIA: nv's hw accel openal requests

Perhaps something else to check is the cpu usage, perhaps there's a noticeable difference. Would expect a hw backend to consume less cpu time.
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Old 08-27-05, 05:51 AM   #6
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Default Re: @NVIDIA: nv's hw accel openal requests

Yes, but therefore I'd need a complex openal only demo - which I don't have.
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Old 08-27-05, 10:03 AM   #7
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Default Re: @NVIDIA: nv's hw accel openal requests

I found another starnge issue with nvopenal:

Positioning is somehow wrong. My test app circles a sound around the listener. What happens with nvopenal is: At 90 and 270 sound doesn't come from L or R, but from the surrounds (I have DPL decoder activated). At 180 sound comes from C, what is expected if you don't encode to surround. But why is (fake?) surround produced in I guess 2ch mode at wrong angles?

What I'd expect is:

- in 2ch stereo mode: At angles bigger about 90 till 270 sound steers back to C (ie from 0 -> 360: C -> R -> C -> L -> C)

-in 2ch surround mode: At angles bigger about 90 till 270 sound steers to surround (ie from 0 -> 360: C -> R -> S -> L -> C)

Currently nvopenal is doing: C -> L -> S -> L -> C -> R -> S -> R -> C
which is quite wrong.
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Old 10-16-05, 01:28 AM   #8
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Default Re: @NVIDIA: nv's hw accel openal requests

@nvidia

Any news on this? I wonder whether some nvidia guys are actually reading this...
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Old 11-27-05, 02:01 AM   #9
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Default Re: @NVIDIA: nv's hw accel openal requests

310 driver shows the same issues...
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