[Openal] Playing a source with no buffer

Thu Mar 13 13:34:52 PDT 2008

Hi Tim,

There is a newer X-Fi driver available (ctaud2k.sys version 5.12.1.1187)
from creative.com.

I just test that one here - and playing a Source with no Buffers attached
immediately changes the state to AL_STOPPED.

Dan
Creative Labs, Inc.

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             "Tim Sorrells"                                                
             <tsorrells at breaka                                             
             wayltd.com>                                                To 
                                       "Daniel PEACOCK"                    
             03/13/2008 12:05          <dpeacock at creativelabs.com>         
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                                       <openal at opensource.creative.com>    
                                                                   Subject 
                                       RE: [Openal] Playing a source with  
                                       no buffer                           

I’m using the default OpenAL device, i.e. alcOpenDevice(NULL).
Soundcard: Creative SB X-Fi
Driver: ctaud2k.sys v. 5.12.0001.1144
OS: Win XP Pro Version 2002 SP 2.
I’m running the OpenAL 1.1 SDK from the Creative site.

From: Daniel PEACOCK [mailto:dpeacock at creativelabs.com]
Sent: Thursday, March 13, 2008 12:24 PM
To: Tim Sorrells
Cc: openal at opensource.creative.com
Subject: Re: [Openal] Playing a source with no buffer

I agree that this sounds like a bug. What OpenAL device are you using, and
on which soundcard and OS?

Dan
Creative Labs, Inc.

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                         "Tim Sorrells"                                    
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                                                                   Subject 

                                                         [Openal] Playing  
                                                         a source with no  
                                                         buffer            

I ran into something unexpected while streaming in a wave. What happens is
when the source is created it queues a request in another thread to stream
in the wave data from the harddrive. However the user is free to call Play
on the source at any time, even before any data has been streamed yet. So
the problem is when it calls alSourcePlay on a source with no associated
buffer. What I’m expecting is that it will change to the AL_PLAYING state
immediately, but then the next time OpenAL updates it will realize it has
no data and cycle to AL_STOPPED, the same behavior as if it had run out of
data in an associated buffer. Instead it stays in AL_PLAYING indefinitely
while, of course, not actually playing any sound.

So I don’t think this should be desired behavior. It seems to me either the
state should cycle to AL_STOPPED (or even AL_INITIAL since there’s no sound
data for the source yet) or this should be an invalid operation and an
error should be issued._______________________________________________
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