Psychtoolbox>PsychPortAudio.{mex*} subfunction

[oldyieldInterval, oldMutexEnable, lockToCore1, audioserver_autosuspend, workarounds] = PsychPortAudio(‘EngineTunables’ [, yieldInterval][, MutexEnable][, lockToCore1][, audioserver_autosuspend][, workarounds]);

Return, and optionally set low-level tuneable driver parameters.
The driver must be idle, ie., no audio device must be open, if you want to
change tuneables! These tuneable parameters usually have reasonably chosen
defaults and you should only need to change them to work around bugs or flaws in
your operating system, sound hardware or drivers, or if you have very unusual
needs or setups. Only touch these if you know what you’re doing, probably after
consultation with the Psychtoolbox forum or Wiki. Some of these have potential
to cause serious system malfunctions if not selected properly!

‘yieldInterval’ - If the driver has to perform polling operations, it will
release the cpu for yieldInterval seconds inbetween unsuccessful polling
iterations. Valid range is 0.0 to 0.1 secs, with a reasonable default of 0.001
secs ie. 1 msec.
‘MutexEnable’ - Enable (1) or Disable (0) internal mutex locking of driver data
structures to prevent potential race-conditions between internal processing
threads. Locking is enabled by default. Only disable locking to work around
seriously broken audio device drivers or system setups and be aware that this
may have unpleasant side effects and can cause all kinds of malfunctions by
‘lockToCore1’ - Deprecated: Enable (1) or Disable (0) locking of all audio
engine processing threads to cpu core 1 on Microsoft Windows systems. By default
threads are locked to cpu core 1 to avoid problems with timestamping due to bugs
in some microprocessors clocks and in Microsoft Windows itself. If you’re
confident/certain that your system is bugfree wrt. to its clocks and want to get
a bit more performance out of multi-core machines, you can disable this. You
must perform this setting before you open the first audio device the first time,
otherwise the setting might be ignored. In the current driver this setting is
silently ignored, as a new method of handling this has been implemented.
‘audioserver_autosuspend’ - Enable (1) or Disable (0) automatic suspending of
running desktop audio servers, e.g., PulseAudio, while PsychPortAudio is active.
Default is (1) - suspend while PsychPortAudio does its thing. Desktop sound
servers like the commonly used PulseAudio server can interfere with low level
audio device access and low-latency / high-precision audio timing. For this
reason it is a good idea to switch them to standby (suspend) while a
PsychPortAudio session is active. Sometimes this isn’t needed or not even
desireable. Therefore this option allows to inhibit this automatic suspending of
audio servers.
‘workarounds’ A bitmask to enable various workarounds: +1 = Ignore
Pa_IsFormatSupported() errors, +2 = Don’t even call Pa_IsFormatSupported().

###See also: Open