Documentation for the SGI audio driver of MikMod
------------------------------------------------
Copyright 1996 by Stephan Kanthak


Current version: 0.4, 24/11/1997


1. Copyright

The SGI audio driver is written by Stephan Kanthak in 1996 and the author
grants to distribute it with the MikMod package under the same restrictions
as the library.

2. Options

The SGI audio driver supports two environment variables:

	MM_SGI_FRAGSIZE	- sets size of audio buffer of the MikMod library
	MM_SGI_BUFSIZE	- sets size of audio buffer in audio library

If you encounter any problems concerning crackles or short stops while
playing, feel free to experiment with the values of these variables. The
default values are 20000 for MM_SGI_FRAGSIZE and 40000 for MM_SGI_BUFSIZE.
Increasing MM_SGI_BUFSIZE might result in nonstop sound on slow machines,
but increases latency of interactive applications. MM_SGI_FRAGSIZE should
be set to about half of MM_SGI_BUFSIZE in most cases and needs to be
increased if you own a very slow SGI.

Note that you need to set the variables by setenv (tcsh) or export (bash)!


3. Problems

- MikMod does not compile on my SGI?
  First check out whether you have the SGI audio library (libaudio) or not.
  If the audio library is missing you should upgrade to IRIX 5.3 or newer
  and you will obtain the media development package automatically with it.
  If you own the audio library check out if it is in the linker path.
  Note that only X-Windows frontends can be compiled on SGI's if you
  do not own the ncurses library (which should be the case for many
  installations).

- No sound at all?
  Look at the messages that MikMod prints during startup. Messages from the
  SGI audio driver start with "SGI audio driver:" followed by a statement
  what is going wrong. Send an error report to the author with an almost
  complete machine description and a detailed error description.

- Sound is _very_ noisy?
  Change sample size to 16 bits.

- Sound crackles or stops temporarily?
  Try to increase the value of the environment variable MM_SGI_FRAGSIZE.
  Default is 20000. Switch to mono mode if necessary.

- MikMod applications only react very slowly?
  This is a typical effect on SGI machines because the audio library sets
  up an internal buffer that seems to be quiet large on many installations.
  Try to decrease MM_SGI_BUFSIZE. Default is 40000.


4. Known bugs

- MIKMOD player crashes heavily (and maybe your winterm, too) when changing
  mixing parameters on-the-fly, i.e. while playing.


5. How to contact the author

Stephan Kanthak
e-mail: kanthak@i6.informatik.rwth-aachen.de
