[Openal-devel] openal-soft

[Chris Robinson]

On Wednesday 06 February 2008 05:58:09 pm Lukasz Pawelczyk wrote:
> Thank you again kind sir :-)
> It worked, and quadro works as well.
> Just the game started to crash every time on exit, probably some SI
> specific device closing as well:
>
> $ AvP
> Now exiting Aliens vs Predator!  At least it didn't crash!
> AL lib: ALc.c:1238: exit() 1 device(s) and 1 context(s) NOT deleted
> Segmentation fault

Heh. Seems the game doesn't close the device at all (or delete the sources..). 
Though OpenAL Soft definitely shouldn't crash in that case, as it does try to 
properly close and delete things at the end if anything was left open. Can 
get a backtrace?

> I'm even sure now that SI has stereo duplication to quad (more on that
> later). But even if you'll decide to implement it, please, make it an
> option. I like to know whether I'm having full quad or not, and having
> only two speakers playing instead of four could answer this question
> very fast. Besides all your worries described above could be solved by
> making this optional.

True. I suppose that's doable.

> When I play original FS2 I have proper quadro, when playing BTRL, with
> exactly the same binary (they are compatible) and exactly the same cmd
> line options, just different data i have stereo (fake quadro on SI). So
> it seems that it has to be defined somewhere within data files of these
> games, not the AL initialization probably. So SI is duplicating all/most
> the sounds that are set to stereo/mono, leaving positional ones intact.

Very weird. I have no idea, honestly. I took a quick look through the code, 
but didn't see any stand-out problems.

> Penumbra first.
> It works, pretty much as it should. Its just that we hit the stereo
> duplication again. With SI when I enter menu or intro the sound is
> 'fake' quadro (duplicated, at least most of it), with openal-soft menu
> and intro has only stereo sound but in-game I get proper quadro, hearing
> sounds behind me only in rear speakers. So I think it means that it is
> handled as it should, but SI was duplicating those channels in case of
> stere/mono sound.
> Like I wrote above, would be nice to implement it, but definitely not as
> an obligatory thing, just configurable. There are many cases where I'd
> like to have current openal-soft behaviour.

I should be able to get a stereo duplication option in for the next 
version. :)

> One more thing about testing. I realize that it might be not the best
> place to ask about it but please tell me in telegraphic short what is
> EFX extension you mentioned in earlier post I found wandering through
> this list's archives. Are they populary called eviromental effects? Like
> differences in sounds made in open space and some small closed room with
> metal walls?

That's exactly it. Although it is still new, roughly implemented, and doesn't 
handle all of the effects that Creative's software drivers can do. A couple 
of the reverb paramters aren't handled (and some not handled properly), no 
idea if the low-pass filter is good (though I think it's acceptable), and it 
doesn't do the eaxreverb effect.

> And if basically they are what I think do you know any game 
> that uses them that I could test it? UT2004 maybe?

IIRC, UT2k4 came out before EFX was introduced. I really don't know of any app 
that does EFX, besides a small handful in the SDK (which isn't very easy to 
judge against). Plenty that do EAX (the DSound-style effects extension), but 
not EFX (AL-style effects extension).

> If you made an effort to implement them would be nice to know what to
> look for while testing games as well to provide some feedback about
> that, and maybe compare to windows implementation.

The EFX10Show example in the SDK is the best thing to test it. Some of the 
behaviors of it with Creative's software driver are kind of odd though, but I 
think it's a fair reproduction within spec. Of course, if anyone can find 
more apps that use it (perhaps get people to use it in some open source 
programs), I'd like to hear of them. :)

> It would be also nice to popularize this implementation a little to keep
> you motivated to develop it and let people know that they got a solid
> OpenAL alternative. Some freshmeat/sourceforge projects as mentioned
> earlier would be nice. I also made short note on FS2 forums in my old
> thread about sound statics, but there are windows users mainly :-)

Just letting people know that there are other implementations besides the 
stagnant SI seems to be the best way. And I actually tried to apply for a 
freshmeat/sourceforge project back around christmas time, but neither 
responded.