OpenAL is a library for creation of a virtual 3D world of sound. It is a cross-platform audio application programming interface (API). The application programmer can specify the location, the speed and the direction of the sources of sounds and of the listener.
OpenAL Soft is an LGPL-licensed, cross-platform, software implementation of the OpenAL 3D audio API.
It is a Tcl bindings for OpenAL (open audio library). Now only support playback function. Capture function added to current codebase but not actually verify.
LGPL 2.1, or (at your option) any later version.
openal::list_devices
openal::list_captures
openal::device HANDLE ?-device name?
HANDLE setListener property setting
HANDLE getListener property
HANDLE createSource
HANDLE isValidSource
HANDLE setSource property setting
HANDLE getSource property
HANDLE queueBuffers ?number?
HANDLE unqueueBuffers ?number?
HANDLE playSource
HANDLE pauseSource
HANDLE rewindSource
HANDLE stopSource
HANDLE destroySource
HANDLE createBuffer ?number?
HANDLE isValidBuffer ?index?
HANDLE bufferData format data samplerate ?index?
HANDLE getBuffer property ?index?
HANDLE destroyBuffer
HANDLE close
openal::capture CAPTURE ?-device name? ?-rate samplerate? ?-format format? ?-buffersize size?
CAPTURE start
CAPTURE captureSamples
CAPTURE stop
CAPTURE close
Open AL provides an extension querying mechanism which allows you to know
whether the runtime Open AL implementation supports a specific extension.
If the enumeration extension is supported, we can procede with listing
the audio devices by using openal::list_devices command.
And openal::list_captures list the capture devices.
openal::device is to open a handle to a device, then create and initialize
a context.
setListener setup the listener object property, AL_GAIN (float),
AL_POSITION (list of float, float, float),
AL_VELOCITY (list of float, float, float),
AL_ORIENTATION (list of float, float, float, float, float, float)
getListener retrieve the listener property, AL_GAIN (float),
AL_POSITION (list of float, float, float),
AL_VELOCITY (list of float, float, float),
AL_ORIENTATION (list of float, float, float, float, float, float)
To playback audio, we must create an audio source object, so we can use the
createSource method to create a source object.
setSource setup the source property,
AL_BUFFER, AL_LOOPING (boolean), AL_SOURCE_RELATIVE (boolean),
AL_SOURCE_STATE (string: AL_INITIAL, AL_PLAYING, AL_PAUSED and AL_STOPPED),
AL_PITCH (float), AL_GAIN (float), AL_MIN_GAIN (float), AL_MAX_GAIN (float),
AL_MAX_DISTANCE (float), AL_ROLLOFF_FACTOR (float),
AL_CONE_OUTER_GAIN (float), AL_CONE_INNER_ANGLE (float),
AL_CONE_OUTER_ANGLE (float), AL_REFERENCE_DISTANCE (float),
AL_SEC_OFFSET (float), AL_SAMPLE_OFFSET (float),
AL_POSITION (list of float, float, float),
AL_VELOCITY (list of float, float, float),
AL_ORIENTATION (list of float, float, float, float, float, float)
getSource retrieve the source property, AL_SOURCE_RELATIVE (boolean),
AL_PITCH (float), AL_GAIN (float), AL_MIN_GAIN (float), AL_MAX_GAIN (float),
AL_MAX_DISTANCE (float), AL_ROLLOFF_FACTOR (float),
AL_CONE_OUTER_GAIN (float), AL_CONE_INNER_ANGLE (float),
AL_CONE_OUTER_ANGLE (float), AL_REFERENCE_DISTANCE (float),
AL_BUFFERS_PROCESSED (int), AL_BUFFERS_QUEUED (int),
AL_SEC_OFFSET (float), AL_SAMPLE_OFFSET (float),
AL_POSITION (list of float, float, float),
AL_VELOCITY (list of float, float, float),
AL_ORIENTATION (list of float, float, float, float, float, float)
destroySource is to destory source.
The buffer object is the object actually holding the raw audio stream.
Use the createBuffer method to create a buffer object.
User can specify the number of buffer to create. If user does not specify, the default number is 1.
bufferData format has values:
AL_FORMAT_MONO8, AL_FORMAT_MONO16, AL_FORMAT_STEREO8,
AL_FORMAT_STEREO16
getBuffer retrieve the buffer property, AL_FREQUENCY, AL_BITS, AL_CHANNELS
and AL_SIZE.
destroyBuffer is to destory buffer.
openal::capture is to open a handle to a capture device.
The -buffersize argument specifies the number of sample frames.
-format has values: AL_FORMAT_MONO8, AL_FORMAT_MONO16, AL_FORMAT_STEREO8,
AL_FORMAT_STEREO16.
I only test tclopenal under openSUSE LEAP 42.2 and Ubuntu 14.04.
Users need install libopenal development files. Below is an example for openSUSE:
sudo zypper in openal-soft-devel
Below is an example for Ubuntu:
sudo apt-get install libopenal-dev
Building under most UNIX systems is easy, just run the configure script and then run make. For more information about the build process, see the tcl/unix/README file in the Tcl src dist. The following minimal example will install the extension in the /opt/tcl directory.
$ cd tclopenal
$ ./configure --prefix=/opt/tcl
$ make
$ make install
If you need setup directory containing tcl configuration (tclConfig.sh), below is an example:
$ cd tclopenal
$ ./configure --with-tcl=/opt/activetcl/lib
$ make
$ make install
Using pacman to install OpenAL Soft.
$ pacman -S mingw-w64-x86_64-openal
Put libopenal-1.dll to Windows folder or other available folder.
Next step is to build tclopenal.
$ ./configure --with-tcl=/c/tcl/lib
$ make
$ make install
List devices:
package require openal
set devices [openal::list_devices]
puts "We found:"
foreach device $devices {
puts $device
}
List capture devices:
package require openal
set captures [openal::list_captures]
puts "We found:"
foreach device $captures {
puts $device
}
Cowork with tclsndfile:
# tclopenal example:
# Using openal and libsndfile to play wav/ogg file
#
package require sndfile
package require openal
set bits 16
set channels 2
set samplerate 44100
set alformat AL_FORMAT_STEREO16
if {$argc == 1} {
set name [lindex $argv 0]
} else {
puts "Please give the correct argument!"
exit
}
if {[catch {set data [sndfile snd0 $name READ]}]} {
puts "Read file failed."
exit
} else {
set encoding [dict get $data encoding]
switch $encoding {
{pcm_16} {
set bits 16
}
{pcm_24} {
set bits 24
}
{pcm_32} {
set bits 32
}
{pcm_s8} {
set bits 8
}
{pcm_u8} {
set bits 8
}
default {
set bits 16
}
}
set channels [dict get $data channels]
set samplerate [dict get $data samplerate]
set size [expr [dict get $data frames] * $channels * $bits / 8]
set buffersize [expr $samplerate * $bits / 8]
snd0 buffersize $buffersize
set buffer_number [expr $size / $buffersize + 1]
}
openal::device dev0
dev0 setListener AL_POSITION [list 0 0 1.0]
dev0 setListener AL_VELOCITY [list 0 0 0]
dev0 setListener AL_ORIENTATION [list 0.0 0.0 1.0 0.0 1.0 0.0]
dev0 createSource
dev0 setSource AL_PITCH 1.0
dev0 setSource AL_GAIN 1.0
dev0 setSource AL_POSITION [list 0 0 1.0]
dev0 setSource AL_VELOCITY [list 0 0 0]
dev0 setSource AL_LOOPING 0
if {$channels > 1} {
if {$bits == 8} {
set alformat AL_FORMAT_STEREO8
} else {
set alformat AL_FORMAT_STEREO16
}
} else {
if {$bits == 8} {
set alformat AL_FORMAT_MONO8
} else {
set alformat AL_FORMAT_MONO16
}
}
dev0 createBuffer $buffer_number
# problem: if read file failed, what should I do?
for {set i 0} {$i < $buffer_number} {incr i} {
if {[catch {set buffer [snd0 read_short]}] == 0} {
dev0 bufferData $alformat $buffer $samplerate $i
dev0 setSource AL_BUFFER $i
dev0 playSource
set state [dev0 getSource AL_SOURCE_STATE]
while {[string compare $state "AL_PLAYING"]==0} {
set state [dev0 getSource AL_SOURCE_STATE]
}
}
}
snd0 close
dev0 destroySource
dev0 destroyBuffer
dev0 close
Cowork with tclmpg123:
# tclopenal example:
# Using openal and libmpg123 to play mp3 file
#
package require mpg123
package require openal
set bits 16
set channels 2
set samplerate 44100
set alformat AL_FORMAT_STEREO16
if {$argc == 1} {
set name [lindex $argv 0]
} else {
puts "Please give the correct argument!"
exit
}
if {[catch {set data [mpg123 mpg0 $name]}]} {
puts "Read file failed."
exit
} else {
set bits [dict get $data bits]
set channels [dict get $data channels]
set samplerate [dict get $data samplerate]
set size [expr [dict get $data length] * $channels * $bits / 8]
set buffersize [expr $samplerate * $bits / 8]
mpg0 buffersize $buffersize
set buffer_number [expr $size / $buffersize + 1]
}
openal::device dev0
dev0 setListener AL_POSITION [list 0 0 1.0]
dev0 setListener AL_VELOCITY [list 0 0 0]
dev0 setListener AL_ORIENTATION [list 0.0 0.0 1.0 0.0 1.0 0.0]
dev0 createSource
dev0 setSource AL_PITCH 1.0
dev0 setSource AL_GAIN 1.0
dev0 setSource AL_POSITION [list 0 0 1.0]
dev0 setSource AL_VELOCITY [list 0 0 0]
dev0 setSource AL_LOOPING 0
if {$channels > 1} {
if {$bits == 8} {
set alformat AL_FORMAT_STEREO8
} else {
set alformat AL_FORMAT_STEREO16
}
} else {
if {$bits == 8} {
set alformat AL_FORMAT_MONO8
} else {
set alformat AL_FORMAT_MONO16
}
}
# Load file data to our buffers
dev0 createBuffer $buffer_number
set buffer_index 0
while {$buffer_index < $buffer_number} {
if {[catch {set buffer [mpg0 read]}] == 0} {
dev0 bufferData $alformat $buffer $samplerate $buffer_index
} else {
break
}
incr buffer_index
}
dev0 queueBuffers $buffer_index
# Just for test, get the total number of queued buffers
set buffer_index [dev0 getSource AL_BUFFERS_QUEUED]
set val 0
while {$val < $buffer_index} {
dev0 playSource
set state [dev0 getSource AL_SOURCE_STATE]
while {[string compare $state "AL_PLAYING"]==0} {
set state [dev0 getSource AL_SOURCE_STATE]
}
set val [dev0 getSource AL_BUFFERS_PROCESSED]
}
dev0 unqueueBuffers $buffer_index
mpg0 close
dev0 destroySource
dev0 destroyBuffer
dev0 close
Capture (only for function test)
package require openal
package require sndfile
set savename [clock format [clock seconds] -format %Y%m%d]
append savename ".wav"
sndfile snd1 $savename WRITE -rate 44100 -channels 1 \
-fileformat wav -encoding pcm_16
openal::capture cap0 -rate 44100 -format AL_FORMAT_MONO16 -buffersize 88200
cap0 start
after 500
for {set i 0} {$i < 60} {incr i} {
set buffer [cap0 captureSamples]
if {[string length $buffer] > 0} {
snd1 write_short $buffer
} else {
after 500
}
}
cap0 stop
snd1 close
cap0 close