Re: Streaming issues

Hi,

> Is there a way to poll to see if a buffer is in use or not?

There isn't a way to determine if a Buffer is in use.    (Note the Buffer
state entires in the header file are really pretty useless because one
Buffer could be attached to multiple Sources and therefore could be
'Pending' on one Source, and 'Processed' on another.)

It sounds like you are doing everything correctly in your streaming code
... can you check if your streaming logic works on different OpenAL devices
... e.g. the "Generic Software" device ?

Thanks,

Dan

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                                                                   Subject 
                                       [Openal-devel] Streaming issues     
             03/09/2007 07:22                                              
             PM                                                            
                                                                           
                                                                           
                                                                           
                                                                           




Is there a way to poll to see if a buffer is in use or not?
I took a peek into AL.h, and saw:
/** * Buffer state.  * * Not supported for public use (yet). */
#define AL_UNUSED                                 0x2010
#define AL_PENDING                                0x2011
#define AL_PROCESSED                              0x2012

Which (I think) is what I need, since what I am trying to do now, is
not working out very well.  I get very distorted sound.

What I am trying to do is to stream memory buffers to openAL.
I set up 20 buffers, (         alGenBuffers( NUMBUFFERS, uiBuffers );) then
start feeding the buffers, ( alBufferData((...) ), and then doing
alSourceQueueBuffers(...).
The data size can be as low as 256 bytes, up to a max of 32k bytes,
depending on the codec.  If it is 256, then each read is also 256
bytes, never more, maybe less when reach the end of the video.
I then check alGetSourcei(uiSource, AL_BUFFERS_PROCESSED,
&iBuffersProcessed); to see if any buffers are 'processed/done', and
if so, I unqueued them.  I check alGetError() before & after all
openAL calls just for testing now, to make sure it wasn't a error
above the call I am doing now.

However, I then get some AL_INVALID_OPERATION(0xA004) messages on
alBufferData() call, which is not listed in the SDK for a proper
return?

Assuming it is supposed to be AL_INVALID_VALUE(0xA003), then I know
the data is of the same type/frequency/samples & size, so the only
other thing according to the SDK is "The size parameter is not valid
for the format specified, the buffer is in use, or the data is a NULL
pointer."  That leaves the buffer is in use, but  it was the buffer
returned back from  alSourceUnqueueBuffers(uiSource, 1, &uiBuffer).

I then tracked the array myself, using another array, and marking it
used if I would use it in alSourceQueueBuffers(), and then free it
when alSourceUnqueueBuffers().

This resulted in :  (nodes is just my array that tracks the buffers)
nodes[00] = free    nodes[01] = used nodes[02] = used  nodes[03] = used
nodes[04] = used  nodes[05] = used  nodes[06] = used  nodes[07] = used
nodes[08] = free    nodes[09] = free   nodes[10] = free   nodes[11] = free
nodes[12] = free   nodes[13] = free   nodes[14] = free   nodes[15] = free
nodes[16] = free  nodes[17] = free  nodes[18] = free  nodes[19] = free
~~~~~~done dump~~~~
Using buffer  nodes[00]..
AL_INVALID_OPERATION call -->alBufferData : [0] (size=8144 bytes)
[uiBuffers[0] is the translation]

I should mention that I followed the SDK playstream sample program,
but I do *NOT* fill up all buffers at once.  I just can't do that with
the media I am streaming in, I just get the audio data when available,
then proceed to load it into a buffer.  At max, it loads 1 buffer up
per main loop, then checks if it is being processed, and if not, then
add another buffer.
I then thought maybe the queue used by openAL was moving entries
up/down in the array, where once something is "processed", it moves
the other entries in the array up (or down) but that isn't documented
I don't think, so I didn't account for that.

This is on windows XP, with onboard audio (Nvidia chipset).

So I dunno what to do to fix this issue?
Ideas?


--Jake.
p.s the repository is also down. :(
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