MidiChannelpublic interface MidiChannel A MidiChannel object represents a single MIDI channel.
Generally, each MidiChannel method processes a like-named MIDI
"channel voice" or "channel mode" message as defined by the MIDI specification. However,
MidiChannel adds some "get" methods that retrieve the value
most recently set by one of the standard MIDI channel messages. Similarly,
methods for per-channel solo and mute have been added.
A {@link Synthesizer} object has a collection
of MidiChannels, usually one for each of the 16 channels
prescribed by the MIDI 1.0 specification. The Synthesizer
generates sound when its MidiChannels receive
noteOn messages.
See the MIDI 1.0 Specification for more information about the prescribed
behavior of the MIDI channel messages, which are not exhaustively
documented here. The specification is titled MIDI Reference:
The Complete MIDI 1.0 Detailed Specification, and is published by
the MIDI Manufacturer's Association (
http://www.midi.org).
MIDI was originally a protocol for reporting the gestures of a keyboard
musician. This genesis is visible in the MidiChannel API, which
preserves such MIDI concepts as key number, key velocity, and key pressure.
It should be understood that the MIDI data does not necessarily originate
with a keyboard player (the source could be a different kind of musician, or
software). Some devices might generate constant values for velocity
and pressure, regardless of how the note was performed.
Also, the MIDI specification often leaves it up to the
synthesizer to use the data in the way the implementor sees fit. For
example, velocity data need not always be mapped to volume and/or brightness. |
| Methods Summary |
|---|
| public void | allNotesOff()Turns off all notes that are currently sounding on this channel.
The notes might not die away instantaneously; their decay
rate is determined by the internals of the Instrument.
If the Hold Pedal controller (see
{@link #controlChange(int, int) controlChange})
is down, the effect of this method is deferred until the pedal is
released.
| | public void | allSoundOff()Immediately turns off all sounding notes on this channel, ignoring the
state of the Hold Pedal and the internal decay rate of the current
Instrument.
| | public void | controlChange(int controller, int value)Reacts to a change in the specified controller's value. A controller
is some control other than a keyboard key, such as a
switch, slider, pedal, wheel, or breath-pressure sensor.
The MIDI 1.0 Specification provides standard numbers for typical
controllers on MIDI devices, and describes the intended effect
for some of the controllers.
The way in which an
Instrument reacts to a controller change may be
specific to the Instrument.
The MIDI 1.0 Specification defines both 7-bit controllers
and 14-bit controllers. Continuous controllers, such
as wheels and sliders, typically have 14 bits (two MIDI bytes),
while discrete controllers, such as switches, typically have 7 bits
(one MIDI byte). Refer to the specification to see the
expected resolution for each type of control.
Controllers 64 through 95 (0x40 - 0x5F) allow 7-bit precision.
The value of a 7-bit controller is set completely by the
value argument. An additional set of controllers
provide 14-bit precision by using two controller numbers, one
for the most significant 7 bits and another for the least significant
7 bits. Controller numbers 0 through 31 (0x00 - 0x1F) control the
most significant 7 bits of 14-bit controllers; controller numbers
32 through 63 (0x20 - 0x3F) control the least significant 7 bits of
these controllers. For example, controller number 7 (0x07) controls
the upper 7 bits of the channel volume controller, and controller
number 39 (0x27) controls the lower 7 bits.
The value of a 14-bit controller is determined
by the interaction of the two halves. When the most significant 7 bits
of a controller are set (using controller numbers 0 through 31), the
lower 7 bits are automatically set to 0. The corresponding controller
number for the lower 7 bits may then be used to further modulate the
controller value.
It is possible that the underlying synthesizer
does not support a specific controller message. In order
to verify that a call to controlChange
was successful, use getController.
| | public int | getChannelPressure()Obtains the channel's keyboard pressure.
If the device does not support setting channel pressure,
this method always returns 0. Calling
setChannelPressure will have no effect then.
| | public int | getController(int controller)Obtains the current value of the specified controller. The return
value is represented with 7 bits. For 14-bit controllers, the MSB and
LSB controller value needs to be obtained separately. For example,
the 14-bit value of the volume controller can be calculated by
multiplying the value of controller 7 (0x07, channel volume MSB)
with 128 and adding the
value of controller 39 (0x27, channel volume LSB).
If the device does not support setting a specific controller,
this method returns 0 for that controller.
Calling controlChange will have no effect then.
| | public boolean | getMono()Obtains the current mono/poly mode.
Synthesizers that do not allow changing mono/poly mode
will always return the same value, regardless
of calls to setMono.
| | public boolean | getMute()Obtains the current mute state for this channel.
If the underlying synthesizer does not support
muting this channel, this method always returns
false.
| | public boolean | getOmni()Obtains the current omni mode.
Synthesizers that do not allow changing the omni mode
will always return the same value, regardless
of calls to setOmni.
| | public int | getPitchBend()Obtains the upward or downward pitch offset for this channel.
If the device does not support setting pitch bend,
this method always returns 8192. Calling
setPitchBend will have no effect then.
| | public int | getPolyPressure(int noteNumber)Obtains the pressure with which the specified key is being depressed.
| | public int | getProgram()Obtains the current program number for this channel.
| | public boolean | getSolo()Obtains the current solo state for this channel.
If the underlying synthesizer does not support
solo on this channel, this method always returns
false.
| | public boolean | localControl(boolean on)Turns local control on or off. The default is for local control
to be on. The "on" setting means that if a device is capable
of both synthesizing sound and transmitting MIDI messages,
it will synthesize sound in response to the note-on and
note-off messages that it itself transmits. It will also respond
to messages received from other transmitting devices.
The "off" setting means that the synthesizer will ignore its
own transmitted MIDI messages, but not those received from other devices.
It is possible that the underlying synthesizer
does not support local control. In order
to verify that a call to localControl
was successful, check the return value.
| | public void | noteOff(int noteNumber, int velocity)Turns the specified note off. The key-up velocity, if not ignored, can
be used to affect how quickly the note decays.
In any case, the note might not die away instantaneously; its decay
rate is determined by the internals of the Instrument.
If the Hold Pedal (a controller; see
{@link #controlChange(int, int) controlChange})
is down, the effect of this method is deferred until the pedal is
released.
| | public void | noteOff(int noteNumber)Turns the specified note off.
| | public void | noteOn(int noteNumber, int velocity)Starts the specified note sounding. The key-down velocity
usually controls the note's volume and/or brightness.
If velocity is zero, this method instead acts like
{@link #noteOff(int)}, terminating the note.
| | public void | programChange(int program)Changes a program (patch). This selects a specific
instrument from the currently selected bank of instruments.
The MIDI specification does not
dictate whether notes that are already sounding should switch
to the new instrument (timbre) or continue with their original timbre
until terminated by a note-off.
The program number is zero-based (expressed from 0 to 127).
Note that MIDI hardware displays and literature about MIDI
typically use the range 1 to 128 instead.
It is possible that the underlying synthesizer
does not support a specific program. In order
to verify that a call to programChange
was successful, use getProgram.
| | public void | programChange(int bank, int program)Changes the program using bank and program (patch) numbers.
It is possible that the underlying synthesizer
does not support a specific bank, or program. In order
to verify that a call to programChange
was successful, use getProgram and
getController.
Since banks are changed by way of control changes,
you can verify the current bank with the following
statement:
int bank = (getController(0) * 128)
+ getController(32);
| | public void | resetAllControllers()Resets all the implemented controllers to their default values.
| | public void | setChannelPressure(int pressure)Reacts to a change in the keyboard pressure. Channel
pressure indicates how hard the keyboard player is depressing
the entire keyboard. This can be the maximum or
average of the per-key pressure-sensor values, as set by
setPolyPressure. More commonly, it is a measurement of
a single sensor on a device that doesn't implement polyphonic key
pressure. Pressure can be used to control various aspects of the sound,
as described under {@link #setPolyPressure(int, int) setPolyPressure}.
It is possible that the underlying synthesizer
does not support this MIDI message. In order
to verify that setChannelPressure
was successful, use getChannelPressure.
| | public void | setMono(boolean on)Turns mono mode on or off. In mono mode, the channel synthesizes
only one note at a time. In poly mode (identical to mono mode off),
the channel can synthesize multiple notes simultaneously.
The default is mono off (poly mode on).
"Mono" is short for the word "monophonic," which in this context
is opposed to the word "polyphonic" and refers to a single synthesizer
voice per MIDI channel. It
has nothing to do with how many audio channels there might be
(as in "monophonic" versus "stereophonic" recordings).
It is possible that the underlying synthesizer
does not support mono mode. In order
to verify that a call to setMono
was successful, use getMono.
| | public void | setMute(boolean mute)Sets the mute state for this channel. A value of
true means the channel is to be muted, false
means the channel can sound (if other channels are not soloed).
Unlike {@link #allSoundOff()}, this method
applies to only a specific channel, not to all channels. Further, it
silences not only currently sounding notes, but also subsequently
received notes.
It is possible that the underlying synthesizer
does not support muting channels. In order
to verify that a call to setMute
was successful, use getMute.
| | public void | setOmni(boolean on)Turns omni mode on or off. In omni mode, the channel responds
to messages sent on all channels. When omni is off, the channel
responds only to messages sent on its channel number.
The default is omni off.
It is possible that the underlying synthesizer
does not support omni mode. In order
to verify that setOmni
was successful, use getOmni.
| | public void | setPitchBend(int bend)Changes the pitch offset for all notes on this channel.
This affects all currently sounding notes as well as subsequent ones.
(For pitch bend to cease, the value needs to be reset to the
center position.)
The MIDI specification
stipulates that pitch bend be a 14-bit value, where zero
is maximum downward bend, 16383 is maximum upward bend, and
8192 is the center (no pitch bend). The actual
amount of pitch change is not specified; it can be changed by
a pitch-bend sensitivity setting. However, the General MIDI
specification says that the default range should be two semitones
up and down from center.
It is possible that the underlying synthesizer
does not support this MIDI message. In order
to verify that setPitchBend
was successful, use getPitchBend.
| | public void | setPolyPressure(int noteNumber, int pressure)Reacts to a change in the specified note's key pressure.
Polyphonic key pressure
allows a keyboard player to press multiple keys simultaneously, each
with a different amount of pressure. The pressure, if not ignored,
is typically used to vary such features as the volume, brightness,
or vibrato of the note.
It is possible that the underlying synthesizer
does not support this MIDI message. In order
to verify that setPolyPressure
was successful, use getPolyPressure.
| | public void | setSolo(boolean soloState)Sets the solo state for this channel.
If solo is true only this channel
and other soloed channels will sound. If solo
is false then only other soloed channels will
sound, unless no channels are soloed, in which case all
unmuted channels will sound.
It is possible that the underlying synthesizer
does not support solo channels. In order
to verify that a call to setSolo
was successful, use getSolo.
|
|
