[Openal] repeated "buzz" while streaming with openAL

Daniel PEACOCK dpeacock at creativelabs.com
Thu Sep 20 14:20:18 PDT 2007





Hi Simon,

Writing a wavefile to disc based on the data that you pass to alBufferData
is a good way of testing this.   The Capture example source code in the PC
OpenAL SDK (
http://developer.creative.com/articles/article.asp?cat=1&sbcat=31&top=38&aid=45
 ) has code for doing this.

One other which you could try is using a different OpenAL device (if
available).   You can use the device enumeration extension to find out what
AL devices you have on your system (there is example code in the SDK that
shows how to do this).

Dan
Creative Labs, Inc.

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             "Simon MAZUE"                                                 
             <simon.mazue at enst                                             
             -bretagne.fr>                                              To 
             Sent by:                  "Daniel PEACOCK"                    
             smazue at gmail.com          <dpeacock at creativelabs.com>         
                                                                        cc 
                                       openal at opensource.creative.com      
             09/20/2007 07:38                                      Subject 
             AM                        Re: [Openal] repeated "buzz" while  
                                       streaming with openAL               
                                                                           
                                                                           
                                                                           
                                                                           
                                                                           
                                                                           




Hi,

I don't know how it could happen as for each buffer, I collect the exact
number of bytes of the buffer.
Nethertheless, is there a way to know if I copy non-audio data in the
buffer (and which type of data) or if it is something else ?

Simon MAZUE


On 9/17/07, Daniel PEACOCK <dpeacock at creativelabs.com> wrote:
  Hi Simon,

  Could it be that some non-audio data is accidently being copied to the
  beginning (or end) of each AL Buffer in your playback code?

  Dan
  Creative Labs, Inc.

  Notice
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  Inactive hide details for Simon MAZUE <smazue at gmail.com>Simon MAZUE <
  smazue at gmail.com>

                                                                           
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                                                                   Subject 
                                                                           
                                                     Re: [Openal] repeated 
                                                     "buzz" while          
                                                     streaming with openAL 
                                                                           
                                                                           
                                                                           
                                                                           
                                                                           
                                                                           






  Hello,

  Thank you for your answers but I tried the two changes (10 buffers of
  17640
  bytes and capture at 48000 hz) and the "buzz" is still here. However,
  it's
  much more frequent with the smaller buffer size. So, it seems that the
  problem comes from the client part.
  And I use windows XP on both side of the system.

  thanks again for your help.

  --
  Simon MAZUE





  Daniel PEACOCK wrote:
  >
  >
  >
  >
  >
  > Hi Simon,
  >
  > It would be useful to know at what stage things have gone wrong ...
  during
  > capture, during transmission across the network to the 2nd PC, or
  during
  > playback.   This can be determined by writing a wave file to disc at
  the
  > different stages - e.g write a wavefile to disc based on what you
  receive
  > from the capture buffer on the first PC, and write another wavefile on
  the
  > 2nd PC based on the audio data it receives.
  >
  > Rather than using 2 big buffers of 88200 you would probably be better
  off
  > using more buffers of smaller sizes, e.g use 10 buffers of 17640 bytes.
  >
  > Also which OS are you using?
  >
  > Dan
  > Creative Labs, Inc.
  >
  > Notice
  > The information in this message is confidential and may be legally
  > privileged.  It is intended solely for the addressee.  Access to this
  > message by anyone else is unauthorized.  If you are not the intended
  > recipient,  any disclosure,  copying or distribution of the message,
  or
  > any action taken by you in reliance on it,  is prohibited and may be
  > unlawful.  If you have received this message in error,  please delete
  it
  > and contact the sender immediately.  Thank you.
  >
  >
  >
  >
  >

  >              Jason Daly

  >              <jdaly at ist.ucf.ed

  >              u>
  To
  >              Sent by:                  Simon MAZUE <smazue at gmail.com>

  >              openal-bounces at op
  cc
  >              ensource.creative         openal at opensource.creative.com

  >              .com
  Subject
  >                                        Re: [Openal] repeated "buzz"
  while
  >                                        streaming with openAL

  >              09/14/2007 07:37

  >              AM

  >

  >

  >

  >

  >
  >
  >
  >
  > Simon MAZUE wrote:
  >> Hello,
  >>
  >> I am trying to stream the sound from a PC to another PC using OpenAL.
  I
  >> capture it and send it in PCM (44100 Hz) but what I obtain on my other
  PC
  > is
  >> the same sound cut by "buzz" every time the buffer changes (2 buffer
  of
  >> 88200 bytes).
  >>
  >> I have tried many changes but with no success. However, it seems to be
  my
  >> "client" application which causes the problem. Is there someone who
  has
  > any
  >> clue of where this comes from and how to stop it ?
  >>
  >
  > Not that this is a solution, but what happens if you capture and send
  at
  > 48000 hz?
  >
  > --"J"
  >
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