[Opalvoip-devel] ptlib sound plugin

[mattes <mk...@my...>]

To extract the sound from an opal session (sip/h323) I created
a new PTlib plugin  shm_pwplugin.so.

I use simpleopal for testing.
   simpleopal --sound-out shm h323:192.168.15.133

Once the connection is established, sound is streamed
via SHM. A semaphore informs the consumer about new sound buffers.

>From testing with the alsa plugin I know there are roughly
50-60 write cycles per second (640 bytes buffer).

When using the shm plugin, i'll get tenthousands of write cycles.
far too many, so something is wrong.

The variable 'lastWriteCount' seems to be important for the interface. I
tried a couple of different settings to no avail.

  PBoolean
  PSoundChannelIPM::Write (const void *buf, PINDEX len)
  {
    lastWriteCount = 0;
    PWaitAndSignal m(device_mutex);

    if ((!isInitialised && !Setup()) || !len || !os_handle)
      return PFalse;

    writeSample2SHM( (void*)buf, len );
    lastWriteCount += len;
    return PTrue;
  }

Does someone know the ptlib plugin API.
I am doing obviously something wrong.

any pointers are appreciated.

mattes