Re: EsounD stuff. was[Re: midi player?]

[Soren Harward <soren cinternet net>]

MODs (and their relatives S3M's MTM's IT's XM's) and MIDI files are based
on the same sort of concept: a set of sound samples and then a pattern of
events dictating how those samples are to be played back to reproduce the
music.  With MOD music, the samples are created and stored as wave files
embedded into the module itself, whereas with MIDI files the samples are
independent of the file and stored in the sound card.  Both files are
played back on an "event" basis: the file is organized into parallel
tracks split into frames.  Each frame is either blank, indicating
"keep playing the current sound as you have been" or contains an
instruction to modify either the sample being played, its frequency, its
volume, or various effects like panning or vibrato.  For instance:

	Track1		Track2		Track3
Frame1  C-4 S10 V64	E-4 S05 V48	G-4 S02 V32

simultaneously lays sample 10 at middle C with volume 64, sample 5 with
pitch E at volume 48, and sample 2 pitch G volume 32.  If all the samples
are tuned properly, you get a C major chord.  Then the next frame:

Frame2	D-4 S10 V64	F-4 S05 V48	A-4 S02 V32

plays everything one pitch higher.

Both MODs and MIDI files work in this fashion, except for the samples they
actually use.  When a MOD is "sequenced," the author defines which
waveforms are to be used as which samples.  Advantage: you know the
file will sound the same no matter what program or hardware you use to 
play it back; disadvantage: waveforms eat space, and mixing them eats CPU
time and memory. When a MIDI file is sequenced, the author bases which
instruments he wants to use on a loose "General MIDI" specification, which
says "sample 1 is a grand piano, sample 5 is a harmonica, sample 43 is a
bass drum, etc."  The advantage to this is that it saves a lot of space
and resources because the waveforms are stored and mixed on the sound
card; however, there is guarantee that sample 43 will actually be a bass
drum, so sometimes MIDI files come out sounding kind of funky...

I think that in the EsounD daemon, these two should be handled similarly,
but I think that attempting to mix MIDI files as waveforms into the rest
of the sound is an unneccessarily difficult idea.  More than 99.9% of
sound cards, if they include waveform playback, include MIDI synthesis as
well--even if it is crappy FM synthesis.  We need to take advantage of
this, and save ourselves a lot of trouble.

If you've got a sound card and would like to get some modules to mess
around with, go to my webpage:

http://www.cinternet.net/~soren/modlist.html

Download a player and any module with 4 or 5 dots next to it (pay
attention to the extension--not all players can handle all files), or if
you have access to a DOS system with a soundcard, get a copy of Impulse
Tracker, and start playing with the files themselves.

-------------------------------------------------
                  Soren Harward                  
Assistant Sysadmin/Tech Support - Cinternet, Inc.
   Voice: 891-1228         soren@cinternet.net   
        http://www.cinternet.net/~soren/

Windows 95/98 DOES come with a tool that lets you
rebuild a corrupted Registry.  It's called FDISK.
-------------------------------------------------

On Sat, 13 Jun 1998, Yo 'Ric Dude wrote:

[...]
>3, I'm not entirely certain as to the mod format.
[...]