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GNU Info File
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1998-12-07
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This is Info file mikmod.info, produced by Makeinfo version 1.68 from
the input file mikmod.texi.
Copyright (C) 1998 Miodrag Vallat and others -- see file AUTHORS for
complete list.
This library is free software; you can redistribute it and/or modify
it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.
This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
INFO-DIR-SECTION Programming
START-INFO-DIR-ENTRY
* MikMod: (mikmod). MikMod Sound Library.
END-INFO-DIR-ENTRY
File: mikmod.info, Node: Top, Next: Introduction, Prev: (dir), Up: (dir)
MikMod Sound Library
********************
This manual documents the MikMod Sound Library, version 3.1.
* Menu:
* Introduction:: What is MikMod ?
* Tutorial:: Your first steps with MikMod.
* Using the Library:: A thematic presentation of the library.
* Library Reference:: Detailed description of the functions and variables.
* Index::
File: mikmod.info, Node: Introduction, Next: Tutorial, Prev: Top, Up: Top
Introduction
************
The MikMod sound library is an excellent way for a programmer to add
music and sound effects to an application. It is a powerful and
flexible library, with a simple and easy-to-learn API.
Besides, the library is very portable and runs under a lot of
Unices, as well as under OS/2. Third party individuals also maintain
ports on other systems, including Windows (using DirectX), and BeOS.
MikMod is able to play a wide range of module formats, as well as
digital sound files. It can take advantage of particular features of
your system, such as sound redirection over the network. And due to its
modular nature, the library can be extended to support more sound or
module formats, as well as new hardware or other sound output
capabilities, as they appear.
File: mikmod.info, Node: Tutorial, Next: Using the Library, Prev: Introduction, Up: Top
Tutorial
********
This chapter will describe how to quickly incorporate MikMod's power
into your programs. It doesn't cover everything, but that's a start and
I hope it will help you understand the library's philosophy.
If you have a real tutorial to put here, you're welcome ! Please
send it to me....
* Menu:
* MikMod Concepts:: A few things you'll need to know.
* A Skeleton Program:: The shortest MikMod program.
* Playing Modules:: How to create a simple module player.
* Playing Sound Effects:: How to play simple sound effects.
* More Sound Effects:: How to play more complex sound effects.
File: mikmod.info, Node: MikMod Concepts, Next: A Skeleton Program, Prev: Tutorial, Up: Tutorial
MikMod Concepts
===============
MikMod's sound output is composed of several sound *voices* which are
mixed, either in software or in hardware, depending of your hardware
configuration. Simple sounds, like sound effects, use only one voice,
whereas sound modules, which are complex arrangements of sound effects,
use several voices.
MikMod's functions operate either globally, or at the voice level.
Differences in the handling of sound effects and modules are kept
minimal, at least for the programmer.
The sound playback is done by a *sound driver*. MikMod provides
several sound drivers: different hardware drivers, and some software
drivers to redirect sound in a file, or over the network. You can even
add your own driver, register it to make it known by the library, and
select it.
File: mikmod.info, Node: A Skeleton Program, Next: Playing Modules, Prev: MikMod Concepts, Up: Tutorial
A Skeleton Program
==================
To use MikMod in your program, there are a few steps required:
* Include `mikmod.h' in your program.
* Register the MikMod drivers you need.
* Initialize the library with MikMod_Init() before using any other
MikMod function.
* Give up resources with MikMod_Exit() at the end of your program,
or before when MikMod is not needed anymore.
* Link your application with the MikMod sound library.
Here's a program which meets all those conditions:
/* MikMod Sound Library example program: a skeleton */
#include <mikmod.h>
main()
{
/* register all the drivers */
MikMod_RegisterAllDrivers();
/* initialize the library */
MikMod_Init();
/* we could play some sound here... */
/* give up */
MikMod_Exit();
}
This program would be compiled with the following command line:(1)
`cc -o example example.c -lmikmod'
Although this programs produces no useful result, many things happen
when you run it. The call to `MikMod_RegisterAllDrivers' registers all
the drivers embedded in the MikMod library. Then, `MikMod_Init' chooses
the more adequate driver and initializes it. The program is now ready
to produce sound. When sound is not needed any more, `MikMod_Exit' is
used to relinquish memory and let other programs have access to the
sound hardware.
---------- Footnotes ----------
(1) If MikMod library has been compiled with ALSA and/or EsounD
support, you'll have to add `-lasound' and/or `-lesd' as well.
File: mikmod.info, Node: Playing Modules, Next: Playing Sound Effects, Prev: A Skeleton Program, Up: Tutorial
Playing Modules
===============
Our program is not really useful if it doesn't produce sound. Let's
suppose you've got this good old module, "Beyond music", in the file
`beyond_music.mod'. How about playing it ?
To do this, we'll use the following code:
/* MikMod Sound Library example program: a simple module player */
#include <unistd.h>
#include <mikmod.h>
main()
{
MODULE *module;
/* register all the drivers */
MikMod_RegisterAllDrivers();
/* register all the module loaders */
MikMod_RegisterAllLoaders();
/* initialize the library */
md_mode|=DMODE_SOFT_MUSIC;
if(MikMod_Init()) {
fprintf(stderr,"Could not initialize sound, reason: %s\n",
MikMod_strerror(MikMod_errno));
return;
}
/* load module */
module = Player_Load("beyond_music.mod",64,0);
if (module) {
/* start module */
Player_Start(module);
while(Player_Active()) {
/* we're playing */
usleep(10000);
MikMod_Update();
}
Player_Stop();
Player_Free(module);
} else
fprintf(stderr,"Could not load module, reason: %s\n",
MikMod_strerror(MikMod_errno));
/* give up */
MikMod_Exit();
}
What's new here ? First, we've not only registered MikMod's device
driver, but also the module loaders. MikMod comes with a large choice
of module loaders, each one for a different module type. Since *every*
loader is called to determine the type of the module when we try to
load them, you may want to register only a few of them to save time. In
our case, we don't matter, so we happily register every module loader.
Then, there's an extra line before calling `MikMod_Init'. We change
the value of MikMod's variable `md_mode' to tell the library that we
want the module to be processed by the software. In fact, there's no
hardware device able to directly play modules, so all modules must be
handled by software mixing.
We'll ensure that `MikMod_Init' was successful. Note that, in case of
error, MikMod provides the variable `MikMod_errno', an equivalent of
the C library `errno' for MikMod errors, and the function
`MikMod_strerror', an equivalent to `strerror'.
Now onto serious business ! The module is loaded with the
`Player_Load' function, which takes the name of the module file, and
the number of voices afforded to the module. In this case, the module
has only 4 channels, so 4 voices, but complex Impulse Tracker modules
can have a lot of voices (as they can have as many as 256 virtual
channels with new note actions). Since empty voices don't cost time to
be processed, it is safe to use a big value, such as 64 or 128. The
third parameter is the "curiosity" of the loader: if nonzero, the
loader will search for hidden parts in the module. However, only a few
module format can embed hidden or non played parts, so we'll use 0 here.
Now that the module is ready to play, let's play it. We inform the
player that the current module is `module' with `Player_Start'.
Playback starts, but we have to update it on a regular basis. So
there's a loop on the result of the `Player_Active' function, which
will tell us if the module has finished. To update the sound, we simply
call `MikMod_Update'.
After the module has finished, we tell the player its job is done
with `Player_Stop', and we free the module with `Player_Free'.
File: mikmod.info, Node: Playing Sound Effects, Next: More Sound Effects, Prev: Playing Modules, Up: Tutorial
Playing Sound Effects
=====================
MikMod is not limited to playing modules, it can also play sound
effects, that is, module samples. It's a bit more complex than playing
a module, because the module player does a lot of things for us, but
here we'll get more control over what is actually played by the
program. Let's look at an example:
/* MikMod Sound Library example program: sound effects */
#include <unistd.h>
#include <mikmod.h>
main()
{
int i;
/* sound effects */
SAMPLE *sfx1,*sfx2;
/* voices */
int v1,v2;
/* register all the drivers */
MikMod_RegisterAllDrivers();
/* initialize the library */
md_mode|=DMODE_SOFT_SNDFX;
if(MikMod_Init()) {
fprintf(stderr,"Could not initialize sound, reason: %s\n",
MikMod_strerror(MikMod_errno));
return;
}
/* load samples */
sfx1 = Sample_Load("first.wav");
if(!sfx1) {
MikMod_Exit();
fprintf(stderr,"Could not load the first sound, reason: %s\n",
MikMod_strerror(MikMod_errno));
return;
}
sfx2 = Sample_Load("second.wav");
if(!sfx2) {
Sample_Free(sfx1);
MikMod_Exit();
fprintf(stderr,"Could not load the second sound, reason: %s\n",
MikMod_strerror(MikMod_errno));
return;
}
/* reserve 2 voices for sound effects */
MikMod_SetNumVoices(-1,2);
/* get ready to play */
MikMod_EnableOutput();
/* play first sample */
v1=Sample_Play(sfx1,0,0);
for(i=0;i<5;i++) {
MikMod_Update();
usleep(100000);
}
/* half a second later, play second sample */
v2=Sample_Play(sfx2,0,0);
do {
MikMod_Update();
usleep(100000);
} while(!Voice_Stopped(v2));
MikMod_DisableOutput();
Sample_Free(sfx2);
Sample_Free(sfx1);
MikMod_Exit();
}
As in the previous example, we begin by registering the sound
drivers and initializing the library. We also ask for software mixing
by modifying the variable `md_mode'(1).
It's time to load our files, with the `Sample_Load' function. Don't
forget to test the return value -- it looks ugly here on such a small
example, but it's a good practice....
Since we want to play two samples, we have to use at least two
voices for this, so we reserve them with a `MikMod_SetNumVoices' call.
The first parameter sets the number of module voices, and the second
parameter the number of sound effect voices. We don't want to set the
number of module voices here (it's part of the module player's duty),
so we use the value `-1' to keep the current value, and we reserve two
sound effect voices.
Now we're ready to play, so we call `MikMod_EnableOutput' to make the
driver ready. Sound effects are played by the `Sample_Play' function.
You just have to specify which sample you want to play, the offset from
which you want to start, and the playback flags. More on this later.
The function returns the number of the voice associated to the sample.
We play the first sample for half a second, then we start to play
the second sample. Since we've reserved two channels, both samples play
simultaneously. We use the `Voice_Stopped' function to stop the
playback: it returns the current status of the voice argument, which is
zero when the sample plays and nonzero when it has finished. So the
`do' loop will stop exactly when the second sample is finished,
regardless of the length of the first sample.
To finish, we get rid of the samples with `Sample_Free'.
---------- Footnotes ----------
(1) Currently, MikMod's drivers don't have support for hardware
mixing.
File: mikmod.info, Node: More Sound Effects, Prev: Playing Sound Effects, Up: Tutorial
More Sound Effects
==================
Sound effects have some attributes that can be affected to control
the playback. These are speed, panning, and volume. Given a voice
number, you can affect these attributes with the `Voice_SetFrequency',
`Voice_SetPanning' and `Voice_SetVolume' functions.
In the previous example, we'll replace the actual sound code,
located between the calls to `MikMod_EnableOutput' and
`MikMod_DisableOutput', with the following code:
Sample_Play(sfx1,0,0);
for(i=0;i<5;i++) {
MikMod_Update();
usleep(100000);
}
v2=Sample_Play(sfx2,0,SFX_CRITICAL);
i=0;
do {
MikMod_Update();
usleep(100000);
v1=Sample_Play(sfx1,0,0);
Voice_SetVolume(v1,160);
Voice_SetFrequency(v1,(sfx1->speed*(100+i))/100);
Voice_SetPanning(v2,(i++&1)?PAN_LEFT:PAN_RIGHT);
} while(!Voice_Stopped(v2));
The first thing you'll notice, is the `SFX_CRITICAL' flag used to
play the second sample. Since the `do' loop will add another sample
every 100 milliseconds, and we reserved only two voices, the oldest
voice will be cut each time this is necessary. Doing this would cut the
second sample in the second iteration of the loop. However, since we
flagged this sound as "critical", it won't be cut until it is finished
or we stop it with a `Voice_Stop' call. So the second sample will play
fine, whereas the first sample will be stopped every loop iteration.
Then, we choose to play the first sample a bit lower, with
`Voice_SetVolume'. Volume voices range from 0 (silence) to 256. In this
case we play the sample at 160. To make the sound look weird, we also
change its frequency with `Voice_SetFrequency'. The computation in the
example code makes the frequency more and more high (starting from the
sample frequency and then increasing from 1% each iteration).
And to demonstrate the `Voice_SetPanning' function, we change the
panning of the second sample at each iteration from the left to the
right. The argument can be one of the standard panning `PAN_LEFT',
`PAN_RIGHT', `PAN_MIDDLE' and `PAN_SURROUND'(1), or a numeric value
between 0 (`PAN_LEFT') and 255 (`PAN_RIGHT').
---------- Footnotes ----------
(1) `PAN_SURROUND' will be mapped to `PAN_MIDDLE' if the library is
initialized without surround sound, that is, if the variable `md_mode'
doesn't have the bit `DMODE_SURROUND' set.
File: mikmod.info, Node: Using the Library, Next: Library Reference, Prev: Tutorial, Up: Top
Using the Library
*****************
This chapter describes the various parts of the library and their
uses.
* Menu:
* Library Version::
* Type Definitions::
* Error Handling::
* Library Initialization::
* Samples and Voice Control::
* Modules and Player Control::
File: mikmod.info, Node: Library Version, Next: Type Definitions, Prev: Using the Library, Up: Using the Library
Library Version
===============
If your program is dynamically linked with the MikMod library, you
should check which version of the library you're working with. To do
this, the library defines a few constants and a function to help you
determine if the current library is adequate for your needs or if it
has to be upgraded.
When your program includes `mikmod.h', the following constants are
defined:
* `LIBMIKMOD_VERSION_MAJOR' is equal to the major version number of
the library.
* `LIBMIKMOD_VERSION_MINOR' is equal to the minor version number of
the library.
* `LIBMIKMOD_REVISION' is equal to the revision number of the
library.
* `LIBMIKMOD_VERSION' is the sum of `LIBMIKMOD_VERSION_MAJOR'
shifted 16 times, `LIBMIKMOD_VERSION_MINOR' shifted 8 times, and
`LIBMIKMOD_REVISION'.
So your program can tell with which version of the library it has
been compiled this way:
printf("Compiled with MikMod Sound Library version %ld.%ld.%ld\n",
LIBMIKMOD_VERSION_MAJOR,
LIBMIKMOD_VERSION_MINOR,
LIBMIKMOD_REVISION);
The library defines the function `MikMod_GetVersion' which returns
the value of LIBMIKMOD_VERSION for the library. If this value is
greater than or equal to the value of LIBMIKMOD_VERSION for your
program, your program will work; otherwise, you'll have to inform the
user that he has to upgrade the library:
{
long engineversion=MikMod_GetVersion();
if (engineversion<LIBMIKMOD_VERSION) {
printf("MikMod library version (%ld.%ld.%ld) is too old.\n",
(engineversion>>16)&255,
(engineversion>>8)&255,
(engineversion)&255);
printf("This programs requires at least version %ld.%ld.%ld\n",
LIBMIKMOD_VERSION_MAJOR,
LIBMIKMOD_VERSION_MINOR,
LIBMIKMOD_REVISION);
puts("Please upgrade your MikMod library.");
exit(1);
}
}
File: mikmod.info, Node: Type Definitions, Next: Error Handling, Prev: Library Version, Up: Using the Library
Type Definitions
================
MikMod defines several data types to deal with modules and sample
data. These types have the same memory size on every platform MikMod
has been ported to.
These types are:
* `CHAR' is a printable character. For now it is the same as the
`char' type, but in the future it may be wide char (Unicode) on
some platforms.
* `SBYTE' is a signed 8 bit number (can range from -128 to 127).
* `UBYTE' is an unsigned 8 bit number (can range from 0 to 255).
* `SWORD' is a signed 16 bit number (can range from -32768 to 32767).
* `UWORD' is an unsigned 16 bit number (can range from 0 to 65535).
* `SLONG' is a signed 32 bit number (can range from -2.147.483.648 to
2.147.483.647).
* `ULONG' is an unsigned 32 bit number (can range from 0 to
4.294.967.296).
* `BOOL' is a boolean value. A value of 0 means false, any other
value means true.
File: mikmod.info, Node: Error Handling, Next: Library Initialization, Prev: Type Definitions, Up: Using the Library
Error Handling
==============
Although MikMod does its best to do its work, there are times where
it can't. For example, if you're trying to play a corrupted file,
well, it can't.
A lot of MikMod functions return pointers or `BOOL' values. If the
pointer is `NULL' or the `BOOL' is 0 (false), an error has occurred.
MikMod errors are returned in the variable `MikMod_errno'. Each
possible error has a symbolic error code, beginning with `MMERR_'. For
example, if MikMod can't open a file, `MikMod_errno' will receive the
value `MMERR_OPENING_FILE'.
You can get an appropriate error message to display from the function
`MikMod_strerror'.
There is a second error variable named `MikMod_critical'. As its name
suggests, it is only set if the error lets the library in an unstable
state. This variable can only be set by the functions `MikMod_Init',
`MikMod_SetNumVoices' and `MikMod_EnableOutput'. If one of these
functions return an error and `MikMod_critical' is set, the library is
left in the uninitialized state (i.e. it was not initialized, or
`MikMod_Exit' was called).
If you prefer, you can use a callback function to get notified of
errors. This function must be prototyped as `void MyFunction(void)'.
Then, call `MikMod_RegisterHandler' with your function as argument to
have it notified when an error occurs. There can only be one callback
function registered, but `MikMod_RegisterHandler' will return you the
previous handler, so you can chain handlers if you want to.
File: mikmod.info, Node: Library Initialization, Next: Samples and Voice Control, Prev: Error Handling, Up: Using the Library
Library Initialization and Core Functions
=========================================
To initialize the library, you must register some sound drivers
first. You can either register all the drivers embedded in the library
for your platform with `MikMod_RegisterAllDrivers', or register only
some of them with `MikMod_RegisterDriver'. If you choose to register
the drivers manually, you must be careful in their order, since
`MikMod_Init' will try them in the order you registered them. The
`MikMod_RegisterAllDrivers' function registers the network drivers
first (for playing sound over the network), then the hardware drivers,
then the disk writers, and in last resort, the nosound driver.
Registering the nosound driver first would not be a very good idea....
You can get some printable information regarding the registered
drivers with `MikMod_InfoDriver'; don't forget to call `free' on the
returned string when you don't need it anymore.
After you've registered your drivers, you can initialize the sound
playback with `MikMod_Init'. If you set the variable `md_device' to
zero, which is its default value, the driver will be autodetected, that
is, the first driver in the list that is available on the system will
be used; otherwise only the driver whose order in the list of the
registered drivers is equal to `md_device' will be tried. If your
playback settings, in the variables `md_mixfreq' and `md_mode', are not
supported by the device, `MikMod_Init' will fail.
You can then choose the number of voices you need with
`MikMod_SetNumVoices', and activate the playback with
`MikMod_EnableOutput'.
Don't forget to call `MikMod_Update' as often as possible to process
the sound mixing. If necessary, fork a dedicated process to do this.
If you want to change playback settings, most of them can't be
changed on the fly. You'll need to stop the playback and reinitialize
the driver. Use `MikMod_Active' to check if there is still sound
playing; in this case, call `MikMod_DisableOutput' to end playback.
Then, change your settings and call `MikMod_Reset'. You're now ready to
select your number of voices and restart playback.
When your program ends, don't forget to stop playback and call
`MikMod_Exit' to leave the sound hardware in a coherent state.
File: mikmod.info, Node: Samples and Voice Control, Next: Modules and Player Control, Prev: Library Initialization, Up: Using the Library
Samples and Voice Control
=========================
Currently, MikMod only supports uncompressed mono WAV files as
samples. You can load a sample by calling `Sample_Load' with a
filename, or by calling `Sample_LoadFP' with an open `FILE*' pointer.
These functions return a pointer to a `SAMPLE' structure, or `NULL' in
case of error.
The `SAMPLE' structure has a few interesting fields:
- `speed' contains the frequency of the sample.
- `volume' contains the volume of the sample, ranging from 0
(silence) to 64.
- `panning' contains the panning position of the sample.
Altering one of those fields will affect all voices currently
playing the sample. You can achieve the same result on a single voice
with the functions `Voice_SetFrequency', `Voice_SetVolume' and
`Voice_SetPanning'.
You can also make your sample loop by setting the fields `loopstart'
and `loopend' and or'ing `flags' with `SF_LOOP'. To compute your loop
values, the field `length' will be useful. However, you must know that
all the sample length are expressed in samples, i.e. 8 bits for an 8
bit sample, and 16 bit for a 16 bit sample... Test `flags' for the value
`SF_16BITS' to know this.
If the common forward loop isn't enough, you can play with some
other flags: `SF_BIDI' will make your sample loop "ping pong" (back and
forth), and `SF_REVERSE' will make it play backwards.
To play your sample, use the `Sample_Play' function. This function
will return a voice number which enable you to use the `Voice_xx'
functions.
The sample will play until another sample takes over its voice (when
you play more samples than you reserved sound effect voices), unless it
has been flagged as `SFX_CRITICAL'. You can force it to stop with
`Voice_Stop', or you can force another sample to take over this voice
with `Voice_Play'; however `Voice_Play' doesn't let you flag the new
sample as critical.
Non looping samples will free their voice channel as soon as they
are finished; you can know the current playback position of your sample
with `Voice_GetPosition'. If it is zero, either the sample has finished
playing or it is just beginning; use `Voice_Stopped' to know.
When you don't need a sample anymore, don't forget to free its
memory with `Sample_Free'.
File: mikmod.info, Node: Modules and Player Control, Prev: Samples and Voice Control, Up: Using the Library
Modules and Player Control
==========================
As for the sound drivers, you have to register the module loaders
you want to use for MikMod to be able to load modules. You can either
register all the module loaders with `MikMod_RegisterAllLoaders', or
only a few of them with `MikMod_RegisterLoader'. Be careful if you
choose this solution, as the 15 instrument MOD loader has to be
registered last, since loaders are called in the order they were
register to identify modules, and the detection of this format is not
fully reliable, so other modules might be mistaken as 15 instrument MOD
files.
You can get some printable information regarding the registered
loaders with `MikMod_InfoLoader'; don't forget to call `free' on the
returned string when you don't need it anymore.
Note that, contrary to the sound drivers, you can register module
loaders at any time, it doesn't matter.
For playlists, you might be interested in knowing the module title
first, and `Player_LoadTitle' will give you this information. Don't
forget to `free' the returned text when you don't need it anymore.
You can load a module either with `Player_Load' and the name of the
module, or with `Player_LoadFP' and an open `FILE*' pointer. These
functions also expect a maximal number of voices, and a curiosity flag.
Unless you have excellent reasons not to do so, choose a big limit,
such as 64 or even 128 for complex Impulse Tracker modules. Both
functions return a pointer to an `MODULE' structure, or `NULL' if an
error occurs.
You'll find some useful information in this structure:
- `numchn' contains the number of module "real" channels.
- `numvoices' contains the number of voices reserved by the player
for the real channels and the virtual channels (NNA).
- `numpas' and `numpat' contain the number of song positions and
song patterns.
- `numins' and `numsmp' contain the number of instruments and
samples.
- `songname' contains the song title.
- `modtype' contains the name of the tracker used to create the song.
- `comment' contains the song comment, if it has one.
- `sngtime' contains the time elapsed in the module, in 2^-10
seconds (not exactly a millisecond).
- `sngspd' and `bpm' contain the song speed and tempo.
Now that the module is loaded, you need to tell the module player
that you want to play this particular module with `Player_Start' (the
player can only play one module, but you can have several modules in
memory). The playback begins. Should you forget which module is
playing, `Player_GetModule' will return it to you.
You can change the current song position with the functions
`Player_NextPosition', `Player_PrevPosition' and `Player_SetPosition',
the speed with `Player_SetSpeed' and `Player_SetTempo', and the volume
(ranging from 0 to 128) with `Player_SetVolume'.
Playback can be paused or resumed with `Player_TogglePause'. Be sure
to check with `Player_Paused' that it isn't already in the state you
want !
Fine player control is achieved by the functions `Player_Mute',
`Player_UnMute' and `Player_ToggleMute' which can silence or resume a
set of module channels. The function `Player_Muted' will return the
state of a given channel. And if you want even more control, you can
get the voice corresponding to a module channel with
`Player_GetChannelVoice' and act directly on the voice.
Modules play only once, but can loop indefinitely if they are
designed to do so. You can change this behavior with the `wrap' and
`loop' of the `MODULE' structure; the first one, if set, will make the
module restart when it's finished, and the second one, if set, will
prevent the module from jumping backwards.
You can test if the module is still playing with `Player_Active',
and you can stop it at any time with `Player_Stop'. When the module
isn't needed anymore, get rid of it with `Player_Free'.
File: mikmod.info, Node: Library Reference, Next: Index, Prev: Using the Library, Up: Top
Library Reference
*****************
This chapter describes in more detail all the functions and
variables provided by the library. *Note Type Definitions:: for the
basic type reference.
* Menu:
* Variable Reference::
* Structure Reference::
* Error Reference::
* Function Reference::
* Loader Reference::
* Driver Reference::
File: mikmod.info, Node: Variable Reference, Next: Structure Reference, Prev: Library Reference, Up: Library Reference
Variable Reference
==================
Error Variables
---------------
The following variables are set by the library to return error
information.
`int MikMod_errno'
When an error occurs, this variable contains the error code.
*Note Error Reference:: for more information.
`BOOL MikMod_critical'
When an error occurs, this variable informs of the severity of the
error. Its value has sense only if the value of `MikMod_errno' is
different from zero. If the value of `MikMod_critical' is zero,
the error wasn't fatal and the library is in a stable state.
However, if it is nonzero, then the library can't be used and has
reseted itself to the uninitialized state. This often means that
the mixing parameters you choose were not supported by the driver,
or that it doesn't has enough voices for your needs if you called
`MikMod_SetNumVoices'.
Sound Settings
--------------
The following variables control the sound output parameters and
their changes take effect immediately.
`UBYTE md_musicvolume'
Volume of the module. Allowed values range from 0 to 128. The
default value is 128.
`UBYTE md_pansep'
Stereo channels separation. Allowed values range from 0 (no
separation, thus mono sound) to 128 (full channel separation). The
default value is 128.
`UBYTE md_reverb'
Amount of sound reverberation. Allowed values range from 0 (no
reverberation) to 15 (a rough estimate for chaos...). The default
value is 6.
`UBYTE md_sndfxvolume'
Volume of the sound effects. Allowed values range from 0 to 128.
The default value is 128.
`UBYTE md_volume'
Overall sound volume. Allowed values range from 0 to 128. The
default value is 96.
Driver Settings
---------------
The following variables control more in-depth sound output
parameters. Except for some `md_mode' flags, their changes do not have
any effect until you call `MikMod_Init' or `MikMod_Reset'.
`UWORD md_device'
This variable contains the order, in the list of the registered
drivers, of the sound driver which will be used for sound
playback. This order is one-based; if this variable is set to
zero, the driver is autodetected, which means the list is tested
until a driver is present on the system. The default value is 0,
thus driver is autodetected.
`MDRIVER* md_driver'
This variable points to the driver which is being used for sound
playback, and is undefined when the library is uninitialized
(before `MikMod_Init' and after `MikMod_Exit'). This variable is
for information only, you should never attempt to change its
value. Use `md_driver' and `MikMod_Init' (or `MikMod_Reset')
instead.
`UWORD md_mixfreq'
Sound playback frequency, in hertz. High values yield high sound
quality, but need more computing power than lower values. The
default value is 44100 Hz, which is compact disc quality. Other
common values are 22100 Hz (radio quality), 11025 Hz (phone
quality), and 8000 Hz (mu-law quality).
`UWORD md_mode'
This variable is a combination of several flags, to select which
output mode to select. The following flags have a direct action
to the sound output (i.e. changes take effect immediately):
`DMODE_INTERP'
This flag, if set, enables the interpolated mixers.
Interpolated mixing gives better sound but takes a bit more
time than standard mixing. If the library is built with the
high quality mixer, interpolated mixing is always enabled,
regardless of this flag.
`DMODE_REVERSE'
This flag, if set, exchanges the left and right stereo
channels.
`DMODE_SURROUND'
This flag, if set, enables the surround mixers. Since
surround mixing works only for stereo sound, this flag has no
effect if the sound playback is in mono.
The following flags aren't taken in account until the sound driver
is changed or reset:
`DMODE_16BIT'
This flag, if set, selects 16 bit sound mode. This mode
yields better sound quality, but needs twice more mixing time.
`DMODE_SOFT_MUSIC'
This flag, if set, selects software mixing of the module.
Since no hardware can play modules at the time of writing,
this flag should always be set.
`DMODE_SOFT_SNDFX'
This flag, if set, selects software mixing of the sound
effects. Currently, no MikMod driver supports hardware mixing
(although some DOS drivers used to do this in the past...),
so you'd better set this flag.
`DMODE_STEREO'
This flag, if set, selects stereo sound.
The default value of this variable is `DMODE_STEREO |
DMODE_SURROUND | DMODE_16BITS | DMODE_SOFT_MUSIC |
DMODE_SOFT_SNDFX'.
File: mikmod.info, Node: Structure Reference, Next: Error Reference, Prev: Variable Reference, Up: Library Reference
Structure Reference
===================
Only the useful fields are described here; if a structure field is
not described, you must assume that it's an internal field which must
not be modified.
Drivers
-------
The `MDRIVER' structure is not meant to be used by anything else
than the core of the library, but its first four fields contain useful
information for your programs:
`CHAR* Name'
Name of the driver, usually never more than 20 characters.
`CHAR* Description'
Description of the driver, usually never more than 50 characters.
`UBYTE HardVoiceLimit'
Maximum number of hardware voices for this driver, 0 if the driver
has no hardware mixing support.
`UBYTE SoftVoiceLimit'
Maximum number of software voices for this driver, 0 if the driver
has no software mixing support.
Modules
-------
The `MODULE' structure gathers all the necessary information needed
to play a module file, regardless of its initial format.
General Module Information
..........................
The fields described in this section contain general information
about the module and should not be modified.
`CHAR* songname'
Name of the module.
`CHAR* modtype'
Type of the module (which tracker format).
`CHAR* comment'
Either the module comments, or NULL if the module doesn't have
comments.
`UWORD flags'
Several module flags or'ed together.
`UF_INST'
If set, the module has instruments and samples; otherwise, the
module has only samples.
`UF_LINEAR'
If set, slide periods are linear; otherwise, they are
logarithmic.
`UF_NNA'
If set, module uses new note actions (NNA) and the
`numvoices' field is valid.
`UF_S3MSLIDES'
If set, module uses old-S3M style volume slides (slide
processed every tick); otherwise, it uses the standard style
(slide processed every tick except the first).
`UF_XMPERIODS'
If set, module uses XM-type periods; otherwise, it uses Amiga
periods.
`UBYTE numchn'
The number of channels in the module.
`UBYTE numvoices'
If the module uses NNA, and this variable is not zero, it contains
the limit of module voices; otherwise, the limit is set to the
`maxchan' parameter of the `Player_Loadxx' functions.
`UWORD numpos'
The number of sound positions in the module.
`UWORD numpat'
The number of patterns.
`UWORD numins'
The number of instruments.
`UWORD numsmp'
The number of samples.
`INSTRUMENT* instruments'
Points to an array of instrument structures.
`SAMPLE* samples'
Points to an array of sample structures.
Playback Settings
.................
The fields described here control the module playback and can be
modified at any time, unless otherwise specified.
`UBYTE initspeed'
The initial speed of the module (Protracker compatible). Valid
range is 1-32.
`UBYTE inittempo'
The initial tempo of the module (Protracker compatible). Valid
range is 32-255.
`UBYTE initvolume'
The initial overall volume of the module. Valid range is 0-128.
`UWORD panning[]'
The current channel panning positions. Only the first `numchn'
values are defined.
`UBYTE chanvol[]'
The current channel volumes. Only the first `numchn' values are
defined.
`UBYTE bpm'
The current tempo of the module. Use `Player_SetTempo' to change
its value.
`UBYTE sngspd'
The current speed of the module. Use `Player_SetSpeed' to change
its value.
`UBYTE volume'
The current overall volume of the module, in range 0-128. Use
`Player_SetVolume' to change its value.
`BOOL extspd'
If zero, Protracker extended speed effect (in-module tempo
modification) is not processed. The default value is 1, which
causes this effect to be processed. However, some old modules
might not play correctly if this effect is not neutralized.
`BOOL panflag'
If zero, panning effects are not processed. The default value is
1, which cause all panning effects to be processed. However, some
old modules might not play correctly if panning is not neutralized.
`BOOL wrap'
If nonzero, module wraps to its restart position when it is
finished, to play continuously. Default value is zero (play only
once).
`UBYTE reppos'
The restart position of the module, when it wraps.
`BOOL loop'
If nonzero, all in-module loops are processed; otherwise, backward
loops which decrease the current position are not processed (i.e.
only forward loops, and backward loops in the same pattern, are
processed). This ensures that the module never loops endlessly.
The default value is 1 (all loops are processed).
`BOOL fadeout'
If nonzero, volume fades out during when last position of the
module is being played. Default value us zero (no fadeout).
`UWORD patpos'
Current position (row) in the pattern being played. Must not be
changed.
`SWORD sngpos'
Current song position. Do not change this variable directly, use
`Player_NextPosition', `Player_PrevPosition' or
`Player_SetPosition' instead.
`ULONG sngtime'
Elapsed song time, in 2^-10 seconds units (not exactly a
millisecond). To convert this value to seconds, divide by 1024.
Module Instruments
------------------
Although the `INSTRUMENT' structure is intended for internal use, you
might need to know its name:
`CHAR* insname'
The instrument text, theoretically its name, but often a message
line.
Samples
-------
The `SAMPLE' structure is used for sound effects and module samples
as well. You can play with the following fields:
`SWORD panning'
Panning value of the sample. Valid values range from PAN_LEFT (0)
to PAN_RIGHT (255), or PAN_SURROUND.
`ULONG speed'
Playing frequency of the sample, it hertz.
`UBYTE volume'
Sample volume. Valid range is 0-64.
`UWORD flags'
Several format flags or'ed together.
Format flags:
`SF_16BITS'
If set, sample data is 16 bit wide; otherwise, it is 8 bit
wide.
`SF_STEREO'
If set, sample data is stereo (two channels); otherwise, it
is mono.
`SF_SIGNED'
If set, sample data is made of signed values; otherwise, it
is made of unsigned values.
`SF_BIG_ENDIAN'
If set, sample data is in big-endian (Motorola) format;
otherwise, it is in little-endian (Intel) format.
`SF_DELTA'
If set, sample is stored as delta values (differences between
two consecutive samples); otherwise, sample is stored as
sample values.
`SF_ITPACKED'
If set, sample data is packed with Impulse Tracker's
compression method; otherwise, sample is not packed.
Playback flags:
`SF_LOOP'
If set, sample loops forward.
`SF_BIDI'
If set, sample loops "ping pong" (back and forth).
`SF_REVERSE'
If set, sample plays backwards.
`ULONG length'
Length of the sample, in *samples*. The length of a sample is 8
bits (1 byte) for a 8 bit sample, and 16 bits (2 bytes) for a 16
bit sample.
`ULONG loopstart'
Loop starting position, relative to the start of the sample, in
samples.
`ULONG loopend'
Loop ending position, relative to the start of the sample, in
samples.
File: mikmod.info, Node: Error Reference, Next: Function Reference, Prev: Structure Reference, Up: Library Reference
Error Reference
===============
The following errors are currently defined:
General Errors
--------------
`MMERR_OPENING_FILE'
This error occurs when a file can not be opened, either for read
access from a `xx_Loadxx' function, or for write access from the
disk writer drivers.
`MMERR_OUT_OF_MEMORY'
This error occurs when there is not enough virtual memory
available to complete the operation, or there is enough memory but
the calling process would exceed its memory limit. MikMod does not
do any resource tuning, your program has to use the `setrlimit'
function to do this if it needs to load very huge samples.
Sample Errors
-------------
`MMERR_OUT_OF_HANDLES'
This error occurs when your program reaches the limit of loaded
samples, currently defined as 384, which should be sufficient for
most cases.
`MMERR_SAMPLE_TOO_BIG'
This error occurs when the memory allocation of the sample data
yields the error `MMERR_OUT_OF_MEMORY'.
`MMERR_UNKNOWN_WAVE_TYPE'
This error occurs when you're trying to load a sample which format
is not recognized.
Module Errors
-------------
`MMERR_ITPACK_INVALID_DATA'
This error occurs when a compressed module sample is corrupt.
`MMERR_LOADING_HEADER'
This error occurs when you're trying to load a module which has a
corrupted header, or is truncated.
`MMERR_LOADING_PATTERN'
This error occurs when you're trying to load a module which has
corrupted pattern data, or is truncated.
`MMERR_LOADING_SAMPLEINFO'
This error occurs when you're trying to load a module which has
corrupted sample information, or is truncated.
`MMERR_LOADING_TRACK'
This error occurs when you're trying to load a module which has
corrupted track data, or is truncated.
`MMERR_MED_SYNTHSAMPLES'
This error occurs when you're trying to load a MED module which
has synthsounds samples, which are currently not supported.
`MMERR_NOT_A_MODULE'
This error occurs when you're trying to load a module which format
is not recognized.
`MMERR_NOT_A_STREAM'
This error occurs when you're trying to load a sample with a
sample which format is not recognized.
Driver Errors
-------------
Generic Driver Errors
.....................
`MMERR_DETECTING_DEVICE'
This error occurs when the driver's sound device has not been
detected.
`MMERR_INITIALIZING_MIXER'
This error occurs when MikMod's internal software mixer could not
be initialized properly.
`MMERR_INVALID_DEVICE'
This error occurs when the driver number (in `md_device') is out
of range.
`MMERR_NON_BLOCK'
This error occurs when the driver is unable to set the audio
device in non blocking mode.
`MMERR_OPENING_AUDIO'
This error occurs when the driver can not open sound device.
`MMERR_16BIT_ONLY'
This driver occurs when the sound device doesn't support non-16
bit linear sound output, which are the requested settings.
AudioFile Driver Specific Errors
................................
`MMERR_AF_AUDIO_PORT'
This error occurs when the AudioFile driver can not find a
suitable AudioFile port.
AIX Driver Specific Errors
..........................
`MMERR_AIX_CONFIG_CONTROL'
This error occurs when the "Control" step of the device
configuration has failed.
`MMERR_AIX_CONFIG_INIT'
This error occurs when the "Init" step of the device configuration
has failed.
`MMERR_AIX_CONFIG_START'
This error occurs when the "Start" step of the device
configuration has failed.
HP-UX Driver Specific Errors
............................
`MMERR_HP_AUDIO_DESC'
This error occurs when the HP driver can not get the audio
hardware description.
`MMERR_HP_AUDIO_OUTPUT'
This error occurs when the HP driver can not select the audio
output.
`MMERR_HP_BUFFERSIZE'
This error occurs when the HP driver can not set the transmission
buffer size.
`MMERR_HP_CHANNELS'
This error occurs when the HP driver can not set the requested
number of channels.
`MMERR_HP_GETGAINS'
This error occurs when the HP driver can not get the audio gains.
`MMERR_HP_SETGAINS'
This error occurs when the HP driver can not set the audio gains.
`MMERR_HP_SETSAMPLESIZE'
This error occurs when the HP driver can not set the requested
sample size.
`MMERR_HP_SETSPEED'
This error occurs when the HP driver can not set the requested
sample rate.
Open Sound System Driver Specific Errors
........................................
`MMERR_OSS_SETFRAGMENT'
This error occurs when the OSS driver can not set audio fragment
size.
`MMERR_OSS_SETSAMPLESIZE'
This error occurs when the OSS driver can not set the requested
sample size.
`MMERR_OSS_SETSPEED'
This error occurs when the OSS driver can not set the requested
sample rate.
`MMERR_OSS_SETSTEREO'
This error occurs when the OSS driver can not set the requested
number of channels.
SGI Driver Specific Errors
..........................
`MMERR_SGI_MONO'
This error occurs when the hardware only supports stereo sound.
`MMERR_SGI_SPEED'
This error occurs when the hardware does not support the requested
sample rate.
`MMERR_SGI_STEREO'
This error occurs when the hardware only supports mono sound.
`MMERR_SGI_16BIT'
This error occurs when the hardware only supports 16 bit sound.
`MMERR_SGI_8BIT'
This error occurs when the hardware only supports 8 bit sound.
Sun Driver Specific Errors
..........................
`MMERR_SUN_INIT'
This error occurs when the sound device initialization failed.
`MMERR_SUN_16BIT_ULAW'
This error occurs when you're trying to use mu-law encoding with
16 bit sound.
OS/2 Driver Specific Errors
...........................
`MMERR_OS2_MIXSETUP'
This error occurs when the DART driver can not set the mixing
parameters.
`MMERR_OS2_SEMAPHORE'
This error occurs when the MMPM/2 driver can not create the
semaphores needed for playback.
`MMERR_OS2_THREAD'
This error occurs when the MMPM/2 driver can not create the thread
needed for playback.
`MMERR_OS2_TIMER'
This error occurs when the MMPM/2 driver can not create the timer
needed for playback.
File: mikmod.info, Node: Function Reference, Next: Library Core Functions, Prev: Error Reference, Up: Library Reference
Function Reference
==================
* Menu:
* Library Core Functions:: MikMod_xx functions.
* Module Player Functions:: Player_xx functions.
* Sample Functions:: Sample_xx functions.
* Voice Functions:: Voice_xx functions.