[Openal] AL_SEC_OFFSET is rounded to nearest 0.5s after play/stop/play

[Daniel PEACOCK]

Hi,

Do you have a test application / source code that shows the problem(s) ?
Does it happen on any other audio devices / soundcards ?

I don't have a SoundStorm to test on, but using my own test application on
the "Generic Hardware" and "Generic Software" devices on an X-Fi card
doesn't show any problems.    Does everything sound ok on the SoundStorm ?
The reason for asking is that the offset position is updated by the
streaming code - so if the offset is wrong then the streaming code may also
be messed up.

A couple of points just in case you haven't realized ...

For a looping Source the playback offset will reset back to zero when the
source re-starts.
When using get offset in seconds you should use alGetSourcef rather than
alGetSourcei (which will be limited to an accuracy of 1 whole second)

Thanks,

Dan

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             "nic at weartronics.                                             
             com"                                                          
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             ensource.creative                                     Subject 
             .com                      Re: [Openal] AL_SEC_OFFSET is       
                                       rounded to nearest 0.5s       after 
                                       play/stop/play                      
             10/10/2006 07:44                                              
             AM                                                            
                                                                           
                                                                           
                                                                           
                                                                           




Dear OpenAL list,

To answer my own question - This problem, and many other very strange
problems I encountered are solved by using the "Generic Software" device
instead of "Generic Hardware" device. So, it seems there are some
problems with the hardware implementation for NVidia SoundStorm on the
NForce chipset.

But one problem persists. I am attaching only one buffer to my source,
and I turn looping on. I note that AL_SEC_OFFSET only returns the
correct time if the buffer size exactly matches the sampling rate
(a.k.a. a one-second buffer). If the buffer size is half of the sampling
rate, AL_SEC_OFFSET returns double the expected time, and if the buffer
size is double the sampling rate, AL_SEC_OFFSET returns half the
expected time. I am not varying the pitch or frequency etc... only the
buffer size. Is there some explanation for this?

Thank you,

Nic

nic at weartronics.com wrote:
> Hi OpenAL list,
>
> If I play a source once and get AL_SEC_OFFSET whilst it is playing I
> get good results (granularity of AL_SEC_OFFSET is very small). If I
> stop the source, then play it again, suddenly AL_SEC_OFFSET is always
> rounded to the nearest 0.5 seconds. I get the same result with
> AL_SAMPLE_OFFSET (rounded to nearest 22050 samples) and AL_BYTE_OFFSET
> (rounded to nearest XXX bytes).
>
> Any clues? Thank you!
>
> Nic
> _______________________________________________
> Openal mailing list
> Openal at opensource.creative.com
> http://opensource.creative.com/mailman/listinfo/openal
>
>
>
>

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