Documentation for the SGI audio driver of MikMod

Current version: 0.4, 24/11/1997

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