midizap/midizap.1

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.TH "midizap" "1" "" "" ""
.hy
.SH Synopsis
.PP
midizap [\-h] [\-k] [\-o[2]] [\-j \f[I]name\f[]] [\-r \f[I]rcfile\f[]]
[\-d[rskmj]]
.SH Options
.TP
.B \-h
Print a short help message.
.RS
.RE
.TP
.B \-k
Keep track of key (on/off) status of MIDI notes and control switches.
This isn't generally recommended, but may occasionally be useful to deal
with quirky controllers sending note\- or control\-ons without
corresponding off messages.
.RS
.RE
.TP
.B \-o[2]
Enable MIDI output.
Add \[lq]2\[rq] for a second pair of MIDI ports to be used, e.g., for
controller feedback.
See Sections \f[I]MIDI Output\f[] and \f[I]Secondary MIDI Ports\f[].
.RS
.RE
.TP
.B \-j \f[I]name\f[]
Set the Jack client name.
Default: \[lq]midizap\[rq].
See Section \f[I]Jack\-Related Options\f[].
.RS
.RE
.TP
.B \-r \f[I]rcfile\f[]
Set the configuration file name.
Default: Taken from the MIDIZAP_CONFIG_FILE environment variable if it
exists, or ~/.midizaprc if it exists, /etc/midizaprc otherwise.
See Section \f[I]Configuration File\f[].
.RS
.RE
.TP
.B \-d[rskmj]
Enable various debugging options: r = regex (print matched translation
sections), s = strokes (print the parsed configuration file in a
human\-readable format), k = keys (print executed translations), m =
midi (MIDI monitor, print all recognizable MIDI input), j = jack
(additional Jack debugging output).
Just \f[C]\-d\f[] enables all debugging options.
See Section \f[I]Basic Usage\f[].
.RS
.RE
.SH Description
.PP
The midizap program translates Jack MIDI input into X keystrokes, mouse
button presses, scroll wheel events, or, as an option, MIDI output.
It does this by matching the \f[C]WM_CLASS\f[] and \f[C]WM_NAME\f[]
properties of the window that has the keyboard focus against the regular
expressions for each application section in its configuration
(midizaprc) file.
If a regex matches, the corresponding set of translations is used.
Otherwise the program falls back to a set of translations in a default
section at the end of the file, if available.
.PP
The midizaprc file is just an ordinary text file which you can edit to
configure the program for use with any kind of application taking
keyboard, mouse or MIDI input.
An example.midizaprc file containing sample configurations for some
applications is included in the sources.
Also, in the examples directory you can find some more examples of
configuration files for various purposes.
.PP
midizap provides you with a way to hook up just about any MIDI
controller to your favorite multimedia applications, like digital audio
workstation (DAW) programs, as well as audio and video editors.
The MIDI output option is useful if the target application supports
MIDI, but can't work directly with your controller because of protocol
incompatibilities.
In particular, you can use midizap to turn pretty much any MIDI
controller with enough faders and buttons into a Mackie\-compatible
mixing device for DAW programs.
Another common use case is video editing software, which rarely offers
built\-in MIDI controller support.
midizap allows you to map the faders, encoders and buttons of your MIDI
controller to corresponding keyboard commands of your video software for
cutting, marking, playback, scrolling and zooming.
.PP
In other words, as long as the target application can be controlled with
simple keyboard shortcuts and/or MIDI commands, chances are that midizap
can make it work with your controller.
.SH Installation
.PP
First, make sure that you have the required dependencies installed.
The program needs a few X11 libraries and Jack.
And of course you need GNU make and gcc (the GNU C compiler).
On Ubuntu and other Debian\-based systems you should be able to get
everything that's needed by running this command:
.IP
.nf
\f[C]
sudo\ apt\ install\ build\-essential\ libx11\-dev\ libxtst\-dev\ libjack\-dev
\f[]
.fi
.PP
Then just run \f[C]make\f[] and \f[C]sudo\ make\ install\f[].
This installs the example.midizaprc file as /etc/midizaprc, and the
midizap program and the manual page in the default install location.
Usually this will be under /usr/local, but the installation prefix can
be changed with the \f[C]prefix\f[] variable in the Makefile.
Also, package maintainers can use the \f[C]DESTDIR\f[] variable as usual
to install into a staging directory for packaging purposes.
.SH Configuration File
.PP
After installation the system\-wide default configuration file will be
in /etc/midizaprc, where the program will be able to find it.
We recommend copying this file to your home directory, renaming it to
\&.midizaprc:
.IP
.nf
\f[C]
cp\ /etc/midizaprc\ ~/.midizaprc
\f[]
.fi
.PP
The ~/.midizaprc file, if it exists, takes priority over /etc/midizaprc,
so it becomes your personal default midizap configuration.
You can edit this file as you see fit, in order to customize existing or
add your own application configurations, adjust the bindings for the
MIDI controllers that you have, etc.
(If you create any new configurations which might be useful for others,
please consider submitting them so that they can be included in future
releases.)
.PP
It is also possible to specify the configuration file to be used, by
invoking midizap with the \f[C]\-r\f[] option on the command line, e.g.:
\f[C]midizap\ \-r\ myconfig.midizaprc\f[].
This is often used with more specialized configurations dealing with
specific applications or MIDI controllers.
.PP
\f[B]NOTE:\f[] The program automatically reloads the midizaprc file
whenever it notices that the file has been changed.
Thus you can edit the file while the program keeps running, and have the
changes take effect immediately without having to restart the program.
When working on new translations, you may want to run the program in a
terminal, and employ some or all of the debugging options explained
below to see exactly how your translations are being processed.
.SH Basic Usage
.PP
The midizap program is a command line application, so you typically run
it from the terminal, but of course it is also possible to invoke it
from your desktop environment's startup files once you've set up
everything to your liking.
.PP
Try \f[C]midizap\ \-h\f[] for a brief summary of the available options
with which the program can be invoked.
.PP
midizap uses Jack (http://jackaudio.org/) for doing all its MIDI input
and output, so you need to be able to run Jack and connect the Jack MIDI
inputs and outputs of the program.
While it's possible to do all of that from the command line as well, we
recommend using a Jack front\-end and patchbay program like
QjackCtl (https://qjackctl.sourceforge.io/) to manage Jack and to set up
the MIDI connections.
In QJackCtl's setup, make sure that you have selected \f[C]seq\f[] as
the MIDI driver.
This exposes the ALSA sequencer ports of your MIDI hardware and other
non\-Jack ALSA MIDI applications as Jack MIDI ports, so that they can
easily be connected to midizap.
.PP
(Here and in the following, we're assuming that you're using Jack1.
Jack2 works in a very similar way, but may require some more fiddling;
in particular, you may have to use
a2jmidid (http://repo.or.cz/a2jmidid.git) as a separate ALSA\-Jack MIDI
bridge in order to have the ALSA MIDI devices show properly as Jack MIDI
devices.)
.PP
Having that set up, start Jack, make sure that your MIDI controller is
connected, and try running \f[C]midizap\f[] from the command line
(without any arguments).
In QJackCtl, open the Connections dialog and activate the second tab
named \[lq]MIDI\[rq], which shows all available Jack MIDI inputs and
outputs.
On the right side of the MIDI tab, you should now see a client named
\f[C]midizap\f[] with one MIDI input port named \f[C]midi_in\f[].
That's the one you need to connect to your MIDI controller, whose output
port should be visible under the \f[C]alsa_midi\f[] client on the left
side of the dialog.
.PP
To test the waters, you can hook up just about any MIDI keyboard and
give it a try with the default section in the distributed midizaprc
file, which contains some basic translations for mouse and cursor key
emulation.
Here is the relevant excerpt from that section:
.IP
.nf
\f[C]
[Default]

\ C5\ \ \ \ XK_Button_1
\ D5\ \ \ \ XK_Button_2
\ E5\ \ \ \ XK_Button_3

\ F5\ \ \ \ XK_Left
\ G5\ \ \ \ XK_Up
\ A5\ \ \ \ XK_Down
\ B5\ \ \ \ XK_Right

\ CC1+\ \ XK_Scroll_Up
\ CC1\-\ \ XK_Scroll_Down
\f[]
.fi
.PP
We refer to Section \f[I]Translation Syntax\f[] below for a discussion
of the syntax being used here, but it should be fairly obvious that
these translations map the white keys of the middle octave (MIDI notes
\f[C]C5\f[] thru \f[C]B5\f[]) to some mouse buttons and cursor commands.
Switch the keyboard focus to some window with text in it, such as a
terminal or an editor window.
Pressing the keys C, D and E should click the mouse buttons, while F
thru B should perform various cursor movements.
Also, moving the modulation wheel (\f[C]CC1\f[]) on your keyboard should
scroll the window contents up and down.
.PP
One useful feature is that you can invoke the program with various
debugging options to get more verbose output as the program recognizes
events from the device and translates them to corresponding mouse
actions or key presses.
E.g., try running \f[C]midizap\ \-drk\f[] to have the program print the
recognized configuration sections and translations as they are executed.
Now press some of the keys and move the modulation wheel.
You should see something like:
.IP
.nf
\f[C]
$\ midizap\ \-drk
Loading\ configuration:\ /home/user/.midizaprc
translation:\ Default\ for\ emacs\@hostname\ (class\ emacs)
CC1\-1\-[]:\ XK_Scroll_Down/D\ XK_Scroll_Down/U\ 
CC1\-1\-[]:\ XK_Scroll_Down/D\ XK_Scroll_Down/U\ 
G5\-1[D]:\ XK_Up/D\ 
G5\-1[U]:\ XK_Up/U\ 
A5\-1[D]:\ XK_Down/D\ 
A5\-1[U]:\ XK_Down/U\ 
\f[]
.fi
.PP
It goes without saying that these debugging options will be very helpful
when you start developing your own bindings.
The \f[C]\-d\f[] option can be combined with various option characters
to choose exactly which kinds of debugging output you want; \f[C]r\f[]
(\[lq]regex\[rq]) prints the matched translation section (if any) along
with the window name and class of the focused window; \f[C]s\f[]
(\[lq]strokes\[rq]) prints the parsed contents of the configuration file
in a human\-readable form whenever the file is loaded; \f[C]k\f[]
(\[lq]keys\[rq]) shows the recognized translations as the program
executes them, in the same format as \f[C]s\f[]; \f[C]m\f[]
(\[lq]MIDI\[rq]) prints \f[I]any\f[] MIDI input, so that you can figure
out which MIDI tokens to use for configuring the translations for your
controller; and \f[C]j\f[] adds some debugging output from the Jack
driver.
You can also just use \f[C]\-d\f[] to enable all debugging output.
(Most of these options are also available as directives in the midizaprc
file; please check the distributed example.midizaprc for details.)
.PP
Have a look at the distributed midizaprc file for more examples.
Most of the other translations in the file assume a Mackie\-like device
with standard playback controls and a jog wheel.
Any standard DAW controller which can be switched into Mackie mode
should work with these.
Otherwise, editing the configuration to make the translations work with
your controller should be a piece of cake.
.SH MIDI Output
.PP
As already mentioned, the midizap program can also be made to function
as a MIDI mapper which translates MIDI input to MIDI output.
MIDI output is enabled by running the program as \f[C]midizap\ \-o\f[].
This equips the Jack client with an additional MIDI output port named
\f[C]midi_out\f[] (visible on the left side of QJackCtl's Connection
window).
.PP
The example.midizaprc file comes with a sample configuration in the
special \f[C][MIDI]\f[] default section for illustration purposes.
This section is only active if the program is run with the \f[C]\-o\f[]
option.
It allows MIDI output to be sent to any connected applications, no
matter which window currently has the keyboard focus.
This is probably the most common way to use this feature, but of course
it is also possible to have application\-specific MIDI translations, in
the same way as with X11 key bindings.
In fact, you can freely mix mouse actions, key presses and MIDI messages
in all translations.
.PP
You can try it and test that it works by running \f[C]midizap\ \-o\f[],
firing up a MIDI synthesizer such as
FluidSynth (http://www.fluidsynth.org/) or its graphical front\-end
Qsynth (https://qsynth.sourceforge.io/), and employing QjackCtl to
connect its input it to midizap's output port.
In the sample configuration, the notes \f[C]C4\f[] thru \f[C]F4\f[] in
the small octave have been set up so that you can operate a little
drumkit, and a binding for the volume controller (\f[C]CC7\f[]) has been
added as well.
The relevant portion from the configuration entry looks as follows:
.IP
.nf
\f[C]
[MIDI]

\ C4\ \ \ \ C3\-10
\ D4\ \ \ \ C#3\-10
\ E4\ \ \ \ D3\-10
\ F4\ \ \ \ D#3\-10

\ CC7=\ \ CC7\-10
\f[]
.fi
.PP
Note the \f[C]\-10\f[] suffix on the output messages in the above
example, which indicates that output goes to MIDI channel 10.
In midizaprc syntax, MIDI channels are 1\-based, so they are numbered
1..16, and 10 denotes the GM (General MIDI) drum channel.
.PP
E.g., the input note \f[C]C4\f[] is mapped to \f[C]C3\-10\f[], the note
C in the third MIDI octave, which on channel 10 will produce the sound
of a bass drum, at least on GM compatible synthesizers like Fluidsynth.
The binding for the volume controller (\f[C]CC7\f[]) at the end of the
entry sends volume changes to the same drum channel (\f[C]CC7\-10\f[]),
so that you can use the volume control on your keyboard to dial in the
volume on the drum channel that you want.
The program keeps track of the values of both input and output
controllers on all MIDI channels internally, so with the translations
above all that happens automagically.
.PP
Please see Section \f[I]Translation Syntax\f[] below for a more detailed
explanation of the syntax used in the configuration file.
Besides MIDI notes and control change (\f[C]CC\f[]) messages, the
midizap program also recognizes program change (\f[C]PC\f[]) and pitch
bend (\f[C]PB\f[]) messages, which should cover most common use cases.
Other messages (in particular, aftertouch and system messages) are not
supported right now, but may be added in the future.
.SH Translation Syntax
.PP
\f[C]#\f[] after whitespace (or at the beginning of a line) indicates
that the rest of the line is a comment.
.PP
The midizap configuration file is a sequence of sections defining
translation classes.
Each section looks like this (\f[C]<X..Y>\f[] indicates ranges of
permitted values, \f[C][...]\f[] optional parts, and \f[C]output\f[]
denotes the output sequence):
.IP
.nf
\f[C]
[name]\ regex
CC<0..127>\ output\ \ \ \ \ \ \ \ \ \ \ #\ control\ change
PC<0..127>\ output\ \ \ \ \ \ \ \ \ \ \ #\ program\ change
PB\ output\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ #\ pitch\ bend
<A..G>[#b]<\-11..11>\ output\ \ #\ note
\f[]
.fi
.PP
When focus is on a window whose class or title matches the regular
expression \f[C]regex\f[], the following translation class is in effect.
An empty regex for the last class will always match, allowing default
translations.
Any output sequences not bound in a matched section will be loaded from
the default section if they are bound there.
.PP
Each \f[C][name]\ regex\f[] line introduces the list of MIDI message
translations for the named translation class.
The name is only used for debugging output, and needn't be unique.
The following lines indicate what output should be produced for the
given MIDI messages.
.PP
The left\-hand side (first token) of each translation denotes the MIDI
message to be translated.
MIDI messages are on channel 1 by default; a suffix of the form
\f[C]\-<1..16>\f[] can be used to specify a different MIDI channel.
E.g., \f[C]C3\-10\f[] denotes note \f[C]C3\f[] on MIDI channel 10.
.PP
Note messages are specified using the customary notation (note name
\f[C]A..G\f[], optionally followed by an accidental, \f[C]#\f[] or
\f[C]b\f[], followed by the MIDI octave number.
Note that all MIDI octaves start at the note C, so \f[C]B0\f[] comes
before \f[C]C1\f[].
By default, \f[C]C5\f[] denotes middle C.
Enharmonic spellings are equivalent, so, e.g., \f[C]D#\f[] and
\f[C]Eb\f[] denote exactly the same MIDI note.
.PP
We will go into most of the other syntactic bits and pieces of MIDI
messages in translations later, but it's good to have the following
grammar in EBNF notation handy for reference:
.IP
.nf
\f[C]
tok\ \ ::=\ (\ note\ |\ msg\ )\ [\ number\ ]\ [\ "["\ number\ "]"\ ]
\ \ \ \ \ \ \ \ \ [\ "\-"\ number]\ [\ incr\ ]
note\ ::=\ (\ "a"\ |\ ...\ |\ "g"\ )\ [\ "#"\ |\ "b"\ ]
msg\ \ ::=\ "ch"\ |\ "pb"\ |\ "pc"\ |\ "cc"
incr\ ::=\ "\-"\ |\ "+"\ |\ "="\ |\ "<"\ |\ ">"\ |\ "~"
\f[]
.fi
.PP
Case is insignificant.
Numbers are always integers in decimal.
The meaning of the first number depends on the context (octave number
for notes, controller or program number in the range 0..127 for other
messages).
This can optionally be followed by a number in brackets, denoting a
nonzero step size.
Also optionally, the suffix with the third number (after the dash)
denotes the MIDI channel in the range 1..16; otherwise the default MIDI
channel is used (which is always 1 on the left\-hand side, but can be
set on the right\-hand side with \f[C]CH\f[]).
The optional incr flag at the end of a token indicates an
\[lq]incremental\[rq] controller or pitch bend value which responds to
numeric (up/down) changes rather than key presses, cf.
\f[I]On/Off vs.\ Incremental Changes\f[] below.
.SS Octave Numbering
.PP
A note on the octave numbers in MIDI note designations is in order here.
There are various different standards for numbering octaves, and
different programs use different standards, which can be rather
confusing.
E.g., there's the ASA (Acoustical Society of America) standard where
middle C is C4, also known as \[lq]scientific\[rq] or \[lq]American
standard\[rq] pitch notation.
At least two other standards exist specifically for MIDI octave
numbering, one in which middle C is C3 (so the lowest MIDI octave starts
at C\-2), and zero\-based octave numbers, which start at C0 and have
middle C at C5.
There's not really a single \[lq]best\[rq] standard here, but the latter
tends to appeal to mathematically inclined and computer\-savvy people,
and is also what is used by default in the midizaprc file.
.PP
However, if you prefer a different numbering scheme then you can easily
change this by specifying the desired offset for the lowest MIDI octave
with the special \f[C]MIDI_OCTAVE\f[] directive in the configuration
file.
For instance:
.IP
.nf
\f[C]
MIDI_OCTAVE\ \-1\ #\ ASA\ pitches\ (middle\ C\ is\ C4)
\f[]
.fi
.PP
This is useful, in particular, if you use some external MIDI monitoring
software to figure out which notes to put into your midizaprc file.
To these ends, just check how the program prints middle C, and adjust
the \f[C]MIDI_OCTAVE\f[] offset in your midizaprc file accordingly.
(Note that midizap's built\-in MIDI monitoring facility always prints
out MIDI notes using the \f[C]MIDI_OCTAVE\f[] offset that is in effect.
Thus in this case the printed note tokens will always be in exactly the
form that is to be used in the midizaprc file, no matter what the
\f[C]MIDI_OCTAVE\f[] offset happens to be.)
.SS On/Off vs.\ Incremental Changes
.PP
By default, all MIDI messages on the left\-hand side of a rule are
interpreted in the same way as keys on a computer keyboard, i.e., they
can be \[lq]on\[rq] (\[lq]pressed\[rq]) or \[lq]off\[rq]
(\[lq]released\[rq]).
For notes, a nonzero velocity means \[lq]pressed\[rq], zero
\[lq]released\[rq].
Similarly, for control changes any nonzero value indicates
\[lq]pressed\[rq].
Same goes for pitch bends, but in this case 0 denotes the center value
(considering pitch bend values as signed quantities in the range
\-8192..8191).
Again, any nonzero (positive or negative) value means \[lq]pressed\[rq],
and 0 (the center value) \[lq]released\[rq].
Finally, while program changes don't actually come in
\[lq]on\[rq]/\[lq]off\[rq] pairs, they are treated in the same key\-like
fashion, assuming that they are \[lq]pressed\[rq] and then
\[lq]released\[rq] immediately afterwards.
.PP
\f[C]CC\f[] (control change) and \f[C]PB\f[] (pitch bend) input messages
can also be marked with a trailing \f[C]+\f[] or \f[C]\-\f[] in the
left\-hand side of a translation.
This changes their meaning, so that they are used to report incremental
(up and down) changes of the controller or pitch bend value instead of
key presses.
.SS Key Translations
.PP
The right\-hand side of a translation (i.e., everything following the
first token) is a sequence of one or more tokens, separated by
whitespace, indicating either MIDI messages or X11 keyboard and mouse
events to be output.
.PP
Let's look at keyboard and mouse output first.
It consists of X key codes (symbolic constants prefixed with
\f[C]XK_\f[] from the /usr/include/X11/keysymdef.h file) with optional
up/down indicators, or strings of printable characters enclosed in
double quotes.
Also, there are some special keycodes to denote mouse button
(\f[C]XK_Button_1\f[], \f[C]XK_Button_2\f[], \f[C]XK_Button_3\f[]) and
scroll wheel (\f[C]XK_Scroll_Up\f[], \f[C]XK_Scroll_Down\f[]) events.
Sequences may have separate press and release sequences, separated by
the special word \f[C]RELEASE\f[].
.PP
Examples:
.IP
.nf
\f[C]
C5\ "qwer"
D5\ XK_Right
E5\ XK_Alt_L/D\ XK_Right
F5\ "V"\ XK_Left\ XK_Page_Up\ "v"
G5\ XK_Alt_L/D\ "v"\ XK_Alt_L/U\ "x"\ RELEASE\ "q"
\f[]
.fi
.PP
Any keycode can be followed by an optional \f[C]/D\f[], \f[C]/U\f[], or
\f[C]/H\f[] flag, indicating that the key is just going down (without
being released), going up, or going down and being held until the
\[lq]off\[rq] event is received.
.PP
So, in general, modifier key codes will be followed by \f[C]/D\f[], and
precede the keycodes they are intended to modify.
If a sequence requires different sets of modifiers for different
keycodes, \f[C]/U\f[] can be used to release a modifier that was
previously pressed with \f[C]/D\f[].
.PP
By default, MIDI messages translate to separate press and release
sequences.
At the end of the press sequence, all down keys marked by \f[C]/D\f[]
will be released, and the last key not marked by \f[C]/D\f[],
\f[C]/U\f[], or \f[C]/H\f[] will remain pressed.
The release sequence will begin by releasing the last held key.
If keys are to be pressed as part of the release sequence, then any keys
marked with \f[C]/D\f[] will be repressed before continuing the
sequence.
Keycodes marked with \f[C]/H\f[] remain held between the press and
release sequences.
.PP
When marking \f[C]CC\f[] (control change) and \f[C]PB\f[] (pitch bend)
input messages with a trailing \f[C]+\f[] or \f[C]\-\f[] in the
left\-hand side of a translation, they are interpreted as
\f[I]incremental changes\f[] instead.
Instead of providing separate press and release sequences, the output of
such translations is executed whenever the controller increases or
decreases, respectively.
At the end of such sequences, all down keys will be released.
For instance, the following translations output the letter \f[C]"a"\f[]
whenever the volume controller (\f[C]CC7\f[]) is increased, and the
letter \f[C]"b"\f[] if it is decreased.
Also, the number of times one of these keys is output corresponds to the
actual change in the controller value.
(Thus, if in the example \f[C]CC7\f[] increases by 32, say, 32
\f[C]"a"\f[]s will be output.)
.IP
.nf
\f[C]
CC7+\ "a"
CC7\-\ "b"
\f[]
.fi
.PP
\f[C]CC\f[] also has an alternative incremental mode which handles
\f[I]relative control changes\f[] encoded in \[lq]sign bit\[rq] format.
Here, a value < 64 denotes an increase, and a value > 64 a decrease
(thus the 7th bit is the sign of the value change).
The lower 6 bits then denote the amount of change (e.g., 2 increments
the control by 2, whereas 66 decrements by 2).
This format is often used with endless rotary encoders, such as the jog
wheel on the Mackie MCU.
It is denoted by using \f[C]<\f[] and \f[C]>\f[] in lieu of \f[C]\-\f[]
and \f[C]+\f[] as the suffix of the CC message.
Example:
.IP
.nf
\f[C]
CC60<\ XK_Left
CC60>\ XK_Right
\f[]
.fi
.PP
Furthermore, incremental \f[C]CC\f[] and \f[C]PB\f[] messages can have a
\f[I]step size\f[] associated with them, which enables you to scale
controller and pitch bend changes.
The default step size is 1 (no scaling).
To change it, the desired step size is written in brackets immediately
after the message token, but before the increment suffix.
Thus, e.g., \f[C]CC1[2]+\f[] denotes a sequence to be executed once
whenever the controller increases by an amount of 2.
As another (more useful) example, \f[C]PB[1170]\f[] will give you 7
steps up and down, which is useful to emulate a shuttle wheel, such as
those on the Contour Design devices, with the pitch bend wheel available
on many MIDI keyboards.
For instance, we might map this to the \f[C]"j"\f[] and \f[C]"k"\f[]
keys used to control the playback speed in various video editors as
follows:
.IP
.nf
\f[C]
PB[1170]\-\ "j"
PB[1170]+\ "l"
\f[]
.fi
.SS MIDI Translations
.PP
Most of the notations for MIDI messages on the left\-hand side of a
translation rule also carry over to the output side, in order to
translate MIDI input to MIDI output.
As already discussed in Section \f[I]MIDI Output\f[] above, you need to
invoke the midizap program with the \f[C]\-o\f[] option to make this
work.
(Otherwise, MIDI messages in the output translations will just be
silently ignored.)
.PP
The output sequence can involve as many MIDI messages as you want, and
these can be combined freely with keypress events in any order.
There's no limitation on the type or number of MIDI messages that you
can put into a translation rule.
.PP
Note that on output, the \f[C]+\-<>\f[] suffixes aren't supported,
because the \f[I]input\f[] message determines whether it is a key press
or value change type of event, and which direction it goes in the latter
case.
.PP
For key press events, such as a note or non\-incremental control change
message, the corresponding \[lq]on\[rq] or \[lq]off\[rq] event is
generated for all MIDI messages in the output sequence, where the
\[lq]on\[rq] value defaults to the maximum value (127 for controller
values, 8191 for pitch bends).
Thus, e.g., the following rule outputs a \f[C]CC80\f[] message with
controller value 127 each time middle C (\f[C]C5\f[]) is pressed:
.IP
.nf
\f[C]
C5\ CC80
\f[]
.fi
.PP
It is also possible to specify a step size in this case, which
explicitly sets the value for the \[lq]on\[rq] state.
For instance, the following variation of the rule above produces a
\f[C]CC80\f[] message with value 64 (rather than the default
\[lq]on\[rq] value of 127) whenever the MIDI note \f[C]C5\f[] is
pressed:
.IP
.nf
\f[C]
C5\ CC80[64]
\f[]
.fi
.PP
On the left\-hand side of a translation, there are two additional
suffixes \f[C]=\f[] and \f[C]~\f[] for incremental \f[C]CC\f[] and
\f[C]PB\f[] messages which are most useful with pure MIDI translations,
which is why we deferred their discussion until now.
If the \[lq]up\[rq] and \[lq]down\[rq] sequences for these messages are
the same, the \f[C]=\f[] suffix can be used to indicate that the same
sequence should be output for both increments and decrements.
For instance, to map the modulation wheel (\f[C]CC1\f[]) to the volume
controller (\f[C]CC7\f[]):
.IP
.nf
\f[C]
CC1=\ CC7
\f[]
.fi
.PP
Which is exactly the same as the two translations:
.IP
.nf
\f[C]
CC1+\ CC7
CC1\-\ CC7
\f[]
.fi
.PP
The same goes for \f[C]<\f[]/\f[C]>\f[] and \f[C]~\f[] with sign\-bit
relative encoders.
Also, on the output side the \f[C]~\f[] suffix can be used to indicate
an incremental \f[C]CC\f[] message in sign\-bit encoding.
Thus, to translate a standard MIDI controller to an endless encoder
value, you might use a rule like:
.IP
.nf
\f[C]
CC1=\ CC60~
\f[]
.fi
.PP
Specifying step sizes with incremental \f[C]CC\f[] and \f[C]PB\f[]
messages works as well, but scales the values \f[I]up\f[] rather than
down on the output side.
This is most commonly used when scaling up controller values to pitch
bends, which cover 128 times the range of a controller:
.IP
.nf
\f[C]
CC1=\ PB[128]
\f[]
.fi
.PP
Another possible use is to scale controller values \f[I]both\f[] down
and up with a combination of step sizes on the left\- and right\-hand
sides, to achieve (an approximation of) a rational scaling factor (2/3
in this example):
.IP
.nf
\f[C]
CC1[3]=\ CC1[2]
\f[]
.fi
.PP
There are two other special tokens on the output side, \f[C]CH\f[] which
selects the default MIDI channel for output, and \f[C]SHIFT\f[] which is
used for processing shift state.
We'll discuss the latter in its own section below.
The \f[C]CH\f[] token, which is followed by a MIDI channel number in the
range 1..16, doesn't actually generate any MIDI message, but merely sets
the default MIDI channel for subsequent MIDI messages in the same output
sequence.
This is convenient if multiple messages are output to the same MIDI
channel.
For instance, the sequence \f[C]C5\-2\ E5\-2\ G5\-2\f[], which outputs a
C major chord on MIDI channel 2, can also be abbreviated as
\f[C]CH2\ C5\ E5\ G5\f[].
.SS Shift State
.PP
The special \f[C]SHIFT\f[] token toggles an internal shift state, which
can be used to generate alternative output for certain MIDI messages.
Please note that, like the \f[C]CH\f[] token, the \f[C]SHIFT\f[] token
doesn't generate any output by itself; it merely toggles the internal
shift bit which can then be queried in other translations to distinguish
between shifted and unshifted bindings for the same input message.
.PP
To these ends, there are two additional prefixes which indicate the
shift status in which a translation is active.
Unprefixed translations are active only in unshifted state.
The \f[C]^\f[] prefix denotes a translation which is active only in
shifted state, while the \f[C]?\f[] prefix indicates a translation which
is active in \f[I]both\f[] shifted and unshifted state.
.PP
Many DAW controllers have some designated shift keys which can be used
for this purpose, but the following will actually work with any
key\-style MIDI message.
E.g., to bind the shift key (\f[C]A#5\f[]) on a Mackie controller:
.IP
.nf
\f[C]
?A#5\ SHIFT
\f[]
.fi
.PP
Note the \f[C]?\f[] prefix indicating that this translation is active in
both unshifted and shifted state, so it is used to turn shift state both
on and off, giving a \[lq]Caps Lock\[rq]\-style of toggle key.
If you'd rather have an ordinary shift key which turns on shift state
when pressed and immediately turns it off when released again, you can
do that as follows:
.IP
.nf
\f[C]
?A#5\ SHIFT\ RELEASE\ SHIFT
\f[]
.fi
.PP
Having set up the translation for the shift key itself, we can now
indicate that a translation should be valid only in shifted state with
the \f[C]^\f[] prefix.
This makes it possible to assign different functions, e.g., to buttons
and faders which depend on the shift state.
Here's a typical example which maps a control change to either
Mackie\-style fader values encoded as pitch bends, or incremental
encoder values:
.IP
.nf
\f[C]
CC48=\ \ PB[129]\-1\ #\ translate\ controller\ to\ pitch\ bend\ when\ unshifted
^CC48=\ CC16~\ \ \ \ \ #\ translate\ controller\ to\ encoder\ when\ shifted
\f[]
.fi
.PP
\f[B]NOTE:\f[] To keep things simple, only one shift status is available
in the present implementation.
Also, when using a shift key in the manner described above, then its
status is \f[I]only\f[] available internally to the midizap program; the
host application never gets to see it.
If your host software does its own handling of shift keys (as most
Mackie\-compatible DAW software does), then it's usually more convenient
to simply pass those keys on to the application and have it take care of
them.
.PP
However, midizap's internal shift status feature may come in handy if
your controller simply doesn't have enough buttons and faders to control
all the essential features of your target application.
In this case the internal shift feature makes it possible to (almost)
double the amount of controls available on the device.
For instance, you can emulate a Mackie controller with both encoders and
faders on a device which only has a single set of faders, by assigning
the shifted faders to the encoders, as shown above.
.SH Jack\-Related Options
.PP
There are some additional directives (and corresponding command line
options) to set midizap's Jack client name and the number of input and
output ports it uses.
(If both the command line options and directives in the midizaprc file
are used, the former take priority, so that it's always possible to
override the options in the midizaprc file from the command line.)
.PP
Firstly, there's the \f[C]\-j\f[] option and the \f[C]JACK_NAME\f[]
directive which change the Jack client name from the default
(\f[C]midizap\f[]) to whatever you want it to be.
To use this option, simply invoke midizap as
\f[C]midizap\ \-j\ client\-name\f[], or put the following directive into
your midizaprc file:
.IP
.nf
\f[C]
JACK_NAME\ "client\-name"
\f[]
.fi
.PP
This option is useful, in particular, if you're running multiple
instances of midizap with different configurations for different
controllers and/or target applications, and you want to have the
corresponding Jack clients named appropriately, so that they can be
identified more easily when wiring them up.
If you're using a persistent MIDI patchbay, such as the one available in
QjackCtl, you can then have the right connections automatically set up
for you whenever you launch midizap with that specific configuration.
.PP
Secondly, we've already seen the \f[C]\-o\f[] option which is used to
equip the Jack client with an additional output port.
This can also be achieved with the \f[C]JACK_PORTS\f[] directive in the
midizaprc file, as follows:
.IP
.nf
\f[C]
JACK_PORTS\ 1
\f[]
.fi
.PP
You may want to place this directive directly into a configuration file
if the configuration is primarily aimed at doing MIDI translations, so
you'd like to have the MIDI output enabled by default.
Typically, such configurations will include just a default
\f[C][MIDI]\f[] section and little else.
As explained below, it's also possible to have \f[I]two\f[] pairs of
input and output ports, in order to deal with controller feedback from
the application.
This is achieved by either invoking midizap with the \f[C]\-o2\f[]
option, or by employing the \f[C]JACK_PORTS\ 2\f[] directive in the
configuration file.
.PP
Last but not least, midizap also supports Jack session management, which
makes it possible to record the options the program was invoked with,
along with all the MIDI connections.
This feature can be used with any Jack session management software.
Specifically, QjackCtl has its own built\-in Jack session manager which
is available in its Session dialog.
To use this, launch midizap and any other Jack applications you want to
have in the session, use QjackCtl to set up all the connections as
needed, and then the \[lq]Save\[rq] (or \[lq]Save and Quit\[rq]) option
in the Session dialog to have the session recorded.
Now, at any later time you can relaunch the same session with the
\[lq]Load\[rq] (or \[lq]Recent\[rq]) option in the same dialog.
.SH Secondary MIDI Ports
.PP
Some MIDI controllers need a more elaborate setup than what we've seen
so far, because they have motor faders, LEDs, etc.
requiring feedback from the application.
To accommodate these, you can use the \f[C]\-o2\f[] option of midizap,
or the \f[C]JACK_PORTS\ 2\f[] directive in the midizaprc file, to create
a second pair of MIDI input and output ports, named \f[C]midi_input2\f[]
and \f[C]midi_output2\f[].
Use of this option also activates a second MIDI default section in the
midizaprc file, labeled \f[C][MIDI2]\f[], which is used exclusively for
translating MIDI from the second input port and sending the resulting
MIDI data to the second output port.
Typically, the translations in the \f[C][MIDI2]\f[] section will be the
inverse of those in the \f[C][MIDI]\f[] section, or whatever it takes to
translate the MIDI feedback from the application back to MIDI data which
the controller understands.
.PP
You then wire up midizap's \f[C]midi_input\f[] and \f[C]midi_output\f[]
ports to controller and application as before, but in addition you also
connect the application back to midizap's \f[C]midi_input2\f[] port, and
the \f[C]midi_output2\f[] port to the controller.
This reverse path is what is needed to translate the feedback from the
application and send it back to the controller.
A full\-blown example for this kind of setup can be found in
examples/APCmini.midizaprc in the sources, which shows how to emulate a
Mackie controller with AKAI's APCmini device, so that it readily works
with DAW software such as Ardour and Reaper.
.PP
You can also use examples/APCmini.midizaprc as a blueprint for your own
Mackie emulations.
If your controller has enough buttons and faders to serve as a mixing
device, you just need to figure out the MIDI messages which the device
generates, and which MIDI messages can be sent back to the device for
controller feedback (if the device supports it).
This information can hopefully be gleaned from your controller's manual
or found on the web somewhere, or you can figure it out on your own by
running midizap with its MIDI monitoring option (\f[C]\-dm\f[]).
.SH Bugs
.PP
There probably are some.
Please submit bug reports and pull requests at the midizap git
repository (https://github.com/agraef/midizap).
.PP
Here are some issues that I'm aware of and which might be addressed in
the future (or not):
.IP \[bu] 2
The names of the various debugging options aren't really very mnemonic
in some cases.
They are the way they are for compatibility with Eric Messick's
ShuttlePRO program on which midizap is based (see below).
.IP \[bu] 2
There's only one internal shift state.
That's unlikely to change, because in cases where multiple shift keys
are needed, the host application most likely already does them, so this
doesn't really seem to be worth the effort.
.IP \[bu] 2
Aftertouch and system exclusive/realtime messages are not supported
right now.
I didn't find any uses for them yet, but at least the system messages
might be good to have.
.IP \[bu] 2
It might be nice to have more options for scaling controller and pitch
bend values, and maybe ways to combine such values, or use them to
specify conditions on a rule (such as restricting the valid range of a
controller).
.SH Notes
.PP
midizap is free and open source software licensed under the GPLv3,
please check the accompanying LICENSE file for details.
.PP
Copyright 2013 Eric Messick (FixedImagePhoto.com/Contact)
.PD 0
.P
.PD
Copyright 2018 Albert Graef (<aggraef@gmail.com>)
.PP
This is a version of Eric Messick's ShuttlePRO program which has been
redesigned to use Jack MIDI instead of the Contour Design Shuttle
devices that the original program was written for.
.PP
ShuttlePRO (https://github.com/nanosyzygy/ShuttlePRO) was originally
written in 2013 by Eric Messick, based on earlier code by Trammell
Hudson (<hudson@osresearch.net>) and Arendt David (<admin@prnet.org>).
The present version of the program is based on Albert Graef's
fork (https://github.com/agraef/ShuttlePRO) of the program.
All the translation features of Eric's version are still there (in
particular, key and mouse translations work exactly the same), but of
course the code has undergone quite some significant changes to
accommodate the MIDI input and output facilities.
The Jack MIDI driver code is based on code from Spencer Jackson's
osc2midi (https://github.com/ssj71/OSC2MIDI) utility, and on the
simple_session_client.c example available in the Jack git
repository (https://github.com/jackaudio/example-clients).