<!DOCTYPE article PUBLIC "-//OASIS//DTD DocBook V4.1//EN" [
<!ENTITY % book "IGNORE">
<!ENTITY % online "INCLUDE">
]>
<!--
MAINTENANCE POLICY
- The person originally entering a question becomes its maintainer. The name of the maintainer is noted at the end of the question.
- Maintainers are allowed to change their questions without notice.
- If you think someone else's question has to be changed, send her or him a patch.
- If you think a new section has to be introduced, make a proposal on tritonus-devel.
- Use four blank lines between sections.
- Use two blank lines between questions.
- Use one blank line between the question and the answer.
- Use one blank line between paragraphs.
- Use "Java Sound", not "JavaSound".
- If you think this policy needs an update, make a proposal on tritonus-devel.
-->
<article>
<articleinfo>
<title>Tritonus FAQ</title>
</articleinfo>
<!-- toc -->
<sect1><title>General</title>
<sect2><title>configure fails. What should I do?</title>
<para>After configure run, there is a file 'config.log in the directory where you run configure. It contains detailed information on failed tests If you want to ask on a mailing list, include the content of this file. (Matthias)
</para>
<sect2><title>I can't get the ALSA mixer.</title>
<para>There are three possibilities:</para>
<ItemizedList>
<ListItem><para>Use a jdk1.3.</para></ListItem>
<ListItem><para>Use an older jdk (e.g. jdk1.2.2) and install
JMF 2.0 performance pack.</para></ListItem>
<ListItem><para>Use an older jdk and install an alternative
Java Sound implementation (e.g. jdk1.2.2 and <ulink
url="http://www.tritonus.org/">Tritonus</ulink>).</para></ListItem>
</ItemizedList>
<para>(Matthias)</para>
<sect2><title>I am new to Java Sound and want to program a
telephony application. Is this possible, and if yes, how do I do
that?</title>
<para>It is possible. We cannot provide all concepts of digital
audio in this FAQ. There are many good books on this subject. I
recommend "the computer music tutorial" from Curtis
Roads, from MIT press. For simple examples how to do streaming
audio with Java Sound, see Matthias' Java Sound
Examples. (Florian)</para>
<sect2><title>How is the JMF related to Java Sound?</title>
<para>JMF is a high-level API, designed mainly for easy playback
of multimedia files, video as well as audio. Java Sound, on the
other hand, is a rather low-level API, designed for detailed
control of the audio hardware. (Matthias)</para>
<!--h3>
I want sun to change or add to the JS API. What can I do?
[use javasound-comments, but cc: to javasound-interestcd]
</h3-->
<sect2><title>I want a specific feature in future versions of the
Java Sound API</title>
<para>You can make specification requests to Sun. To read how to
do that, go to <ulink
url="http://java.sun.com/aboutJava/communityprocess/submit.html">http://java.sun.com/aboutJava/communityprocess/submit.html</ulink>.
You may want to discuss the feature before hand on the mailing
list. (Florian)</para>
<sect2><title>The Java Sound API seems fine to me, but many things
do not seem to be implemented.</title>
<para>This is a matter of time. Sun will improve the Java Sound
implementation (and also the API). Other people will provide
service providers to extend Java Sound. The Tritonus team will
release parts of Tritonus as service providers so that everybody
can take advantage of Tritonus' achievements. A native port of
Tritonus to Windows is planned, too. (Florian)</para>
<sect2><title>I discovered a bug in a Java Sound implementation</title>
<para>For the Sun implementation, you can submit it as a bug on
<ulink
url="http://java.sun.com/cgi-bin/bugreport.cgi">http://java.sun.com/cgi-bin/bugreport.cgi</ulink>
(needs a registration to the developer connection). For
Tritonus, use their bug reporting system on <ulink
url="http://sourceforge.net/bugs/?group_id=1390">http://sourceforge.net/bugs/?group_id=1390</ulink>.
(Florian)</para>
<sect1><title>Audio Programming </title>
<sect2><title>I want to convert a byte[] array to short samples or
vice versa.</title>
<para>Look at the Tritonus source code, class
org.tritonus.sampled.TConversionTool. You have to look it up in
the cvs repository in the subdirectory
src/org/tritonus/sampled. For that, go to <ulink
url="http://cvs.sourceforge.net/cgi-bin/cvsweb.cgi/tritonus/src/org/tritonus/sampled/?cvsroot=tritonus">http://cvs.sourceforge.net/cgi-bin/cvsweb.cgi/tritonus/src/org/tritonus/sampled/?cvsroot=tritonus</ulink>
and click on the version number of
"TConversionTool.java". It contains many methods for
converting byte arrays. (Florian)</para>
<sect2><title>Playback of audio data with Java Sound is
significantly quieter than with a compared player on the native
OS.</title>
<para>There was the issue that Sun's implementation of Java
Sound (at least up to version 0.99) lowers the level of output
in order to avoid clippings when several lines are
mixed. Probably this "feature" is the problem. </para>
<para>I find this "feature" quite doubtful. A Java
Sound programmer should use GainControls attached to single
lines to lower the volume, if wanted. Many applications won't
profit of this "feature": e.g. they only play one line
at a time. Or the mixed sounds don't create clippings. This is
not unusual, as even "normalized" sounds leave most of
the time enough room - there must coincide peaks to create a
clipping. The case that the soft synth AND audio are playing
simultaneously can be expected in "quality" programs
which provide a way to lower the gain of the lines - or do the
gain decrease automatically. </para>
<para>As Java Sound is supposed to be a low-level engine, such
an approach would not be suitable. The problem of the feature is
a general decrease of signal-to-noise ratio of all Java Sound
programs. Automatic lowering of volume prevents the use in
"serious" or professional
environments... (Florian)</para>
<sect2><title>I cannot retrieve any Port instances</title>
<para>It seems that no implementation of Java Sound provides
Port instances, yet. (Florian)</para>
<sect2><title>I want to save audio data to a file, like wav or
aiff</title>
<para>Have look at Matthias' Java Sound Examples. (todo: link -
maybe put them, too, on tritonus.org)</para>
<sect2><title>I want to be notified when data is available for
write/read in a SourceDataLine/TargetDataLine</title>
<para>You have to use
SourceDataLine/TargetDataLine.available(). The usual
implementation for streaming audio (in Java Sound) is a
dedicated thread for that - look at the Java Sound demo which
you can download from sun or at Matthias' JS
examples. (Florian)</para>
<sect2><title>I want to do some processing on an alaw stream (like
amplifing it)</title>
<para>It is much easier to change gain with linear encoding
(PCM). I would strongly suggest that - especially when you have
the data in linear format at first. You'd have to convert it
back to alaw after processing. (Florian)</para>
<sect2><title>I want to implement a real-time AudioInputStream,
but cannot give a length for it, as it is not known in
advance</title>
<para>You should use "AudioSystem.NOT_SPECIFIED" as
length. This approach seems logical to me and it works fine in
my program. (Florian)</para>
<sect2><title>I want to add special chunks to wave or aiff files
(like for a descriptive text or copyright)</title>
<para>The Java Sound API does not support this currently. Future
versions are likely to, because this is indeed quite important.
For the moment, you will need to implement your own class for
writing wave or aiff files. Or make meaningful
filenames... (Florian)</para>
<sect2><title>It fails to open any line with 16KHz sample
rate</title>
<para>Apparently, most Java Sound implementations do not provide
that, even if the sound card supports it. Future implementations
will support that. (Florian)</para>
<sect2><title>I have a byte array and want to write these data to
an audio file.</title>
<para>Create a ByteArrayInputStream object from the byte array,
create an AudioInputStream from it, then call
AudioSystem.write(...). [TODO: code example, alternative
approach via AudioOutputStream] (Matthias)</para>
<sect2><title>I want to get a SourceDataLine or TargetDataLine in
µ-law format</title>
<para>TargetDataLines are supposed to act as a
"direct" way to communicate with the audio hardware
device, i.e. your soundcard. When your soundcard does not
support ulaw directly, the TargetDataLine won't either.</para>
<para>The way to go is to open a TargetDataLine in pcm format
and route it through a format converter. See doc of AudioSystem
to get converted Streams. The converted stream you get provides
ulaw samples then. </para>
<para>There is no drawback in this approach: all PC soundcards
that I know of deliver only PCM, so it has to be rendered to
ulaw anyway in software. Whether in the soundcard's driver, the
operating system layer or in the application (your java program)
doesn't matter. You get maximum portability when only using pcm
for TargetDataLines. (Florian)</para>
<sect2><title>Simultaneous recording and playback only works when
first opening the playback line (SourceDataLine)</title>
<para>This depends on the soundcard and its driver to the native
operating system. E.g. Soundblaster 16 or 64 do not provide real
full duplex, only a kind of pseudo full duplex. I experienced
under Windows that you can only use this pseudo full duplex when
you have a certain order in opening record/playback
lines. (Florian)</para>
<sect2><title>I want to detect the level of sound while I am
recording it</title>
<para>First of all, you should have the data in PCM format
(preferable in signed PCM). Then you can look at the samples to
detect the amplitude (level). Some statistics are suitable, too,
like taking the average of the absolute values or
RMS. (Florian)</para>
<sect2><title>I want to use multi-channel sound.</title>
<para>This is currently not possible. It will be supported in
Tritonus in the future. (Matthias)</para>
<sect2><title>I'm trying to do sample rate conversion with Java
Sound, but it doesn't work.</title>
<para>Currently, no Java Sound implementation supports
this. Tritonus will do so in the near future, and this will be
made available as a plug-in for other Java Sound
implementations. Also, JMF supports sample rate
conversion. (Matthias)</para>
<sect2><title>I want to do equalizing/noise reduction/fft/... with
Java Sound.</title>
<para>Java Sound is an API concerned with basic sound input and
output. It does not contain digital signal processing
algorithms. Nevertheless, you can do this with Java; you just
have to code it on your own. The book "Digital Audio with Java"
by Craig Lindley contains some DSP algorithm. Also, it is often
easy to transform C or C++ code found on the net to Java.</para>
<para>For code that does fft, have a look at the <ulink
url="http://www.seas.smu.edu/~cjuliano/peruna.html">Peruna
Project</ulink>. (Matthias)</para>
<sect2><title>I do recording with a TargetDataLine and I want a
volume control for it.</title>
<para>The obvious solution would be to get a Control object of
type VOLUME or GAIN for the TargetDataLine and manipulate the
volume via this object. However, this is not possible, since
neither the Sun jdk1.3 nor Tritonus implement any controls for
TargetDataLines.</para>
<para>What you can do is to use the system mixer to control the recording
volume---it affects hardware settings in the soundcard. There is an
API to manipulate the system mixer from java: the mysterious
Ports. But again, this is not implemented in any known Java Sound
implementation (it is planned to implement Ports in future versions of
Tritonus).</para>
<para>The remaining possibility is to implement a volume control
digitally: multiplying each single sample of the sound data with
a certain value that lowers or raises the level
proportionally. (Matthias)</para>
<sect2><title>I want to use an audio clip on a 5 MB audio file,
but I get an out of memory exception.</title>
<para>For files of this size, you should stream the audio. Like
that you treat buffers of small size and feed them successively
into the the audio device. Look at Matthias' Java Sound
examples, there are some streaming audio players to take as a
start. Java Sound Examples: <ulink
url="http://rupert.informatik.uni-stuttgart.de/~pfistere/jsexamples/">http://rupert.informatik.uni-stuttgart.de/~pfistere/jsexamples/</ulink>.
(Florian)</para>
<sect2><title>I want to calculate the number of bytes to skip from
the length in seconds.</title>
<para>Use one of the following formulas: bytes = seconds *
sample rate * channels * (bits per sample / 8) or bytes =
seconds * sample rate * frame size. You can get the sample rate,
number of channels, bits per sample and frame size from an
AudioFormat object. (Matthias)</para>
<sect1><title>Encodings and file types</title>
<sect2><title>I want to play back mp3 files</title>
<para>There is a pure Java decoder of the javazoom project.
Tritonus, the open source implementation of Java Sound
incorporates it. There is a plug in available which runs under
any JVM. (Florian)</para>
<sect2><title>I want to encode mp3 files with my Java
program</title>
<para>Java is free, this collides with the (enforced) licences
for mp3 encoders. I have studied very carefully the mp3
licencing model and also asked at Fraunhofer (inventors of mp3)
for additional information: it won't be possible to deliver a
free mp3 encoder legally. (If anyone knows a "hole",
please let me know. (not the available source code - this is not
appropriate: the encoders available as source code - most of
them based on the ISO reference implementation - create bad
quality mp3's and the licence doesn't allow the use of such
encoders!))</para>
<para>The Tritonus team is working on an interface to the open
source encoder <ulink
url="http://www.sulaco.org/mp3/">LAME</ulink>. Like that people
who do not fear licence problems can download LAME as a separate
package and link it to Java Sound. (Florian)</para>
<sect2><title>I want to convert a PCM encoded byte[] to a uLaw
byte[]</title>
<para>When you are processing streams, read the documentation of
javax.sound.sampled.AudioSystem. There are functions like
getAudioInputStream(AudioFormat, AudioInputStream) that do the
conversion for you. </para>
<para>In case you absolutely want to do the conversion "by
hand", look at how Tritonus is doing it: have a look at the
file <ulink
url="http://cvs.sourceforge.net/cgi-bin/cvsweb.cgi/tritonus/src/org/tritonus/sampled/?cvsroot=tritonus">TConversionTool.java</ulink>.
(Florian)</para>
<!--
<sect2><title>
I want to play mp3 files with Java Sound. How can I do this?
</title>
<para>
</para>
<para>
An alternative is to use JMF. It contains a mp3 decoder, too.
</p-->
<!--h3>
I want to add support for a new sound file format. How can I do this?
</h3-->
<sect2><title>Is there support for RealAudio in Java Sound?</title>
<para>There isn't, and it doesn't look like there will be in the
near future. RealAudio is a proprietary format; there is no
specification available to the public. Due to that, it's hard to
implement support for it. If you want to change this situation,
bug RealNetworks to publish specs (politely,
please). (Matthias)</para>
<sect2><title>Is there support for GSM in Java Sound?</title>
<para>Yes, you can download a service provider plug-in for GSM
from <ulink url="http://www.tritonus.org/plugins.html">Java
Sound Plugins</ulink>. Since this implementation is pure-java,
it can be used with any Java Sound implementation on any
platform. For examples of using the GSM plug-in, see the
section "dealing with encodings" in the Java Sound Examples.
(Matthias)</para>
<sect2><title>Java Sound supports a format called RMF. Where can I get
documentation about this format?</title>
<para>You can't. RMF (Rich Music Format) is a proprietary format
designed by beatnik (www.beatnik.com). They don't release any
specs to the public. By the way, it's not true for all Java
Sound implementations to support RMF. Tritonus doesn't for the
above reason. Instead, it will support MPEG-4 Structured
Audio.</para>
<sect2><title>I want to read in a vox file and save it as wav
file</title>
<para>Probably it's simplest to do all by yourself: use a
RandomAccessFile or similar to open the vox file, parse the
headers, etc. You need to know the vox file format, you can find
many documents specifying it on the Internet. To create a wave
file from that, create a AudioFileFormat instance with the
format read from the vox-header and supply an InputStream with
the audi data of the vox file. You can then use
AudioSystem.write to write a wav file. (Florian)</para>
<sect1><title>MIDI</title>
<sect2><title>MIDI input seems not to work with the Sun jdk1.3.
</title>
<para>
The Sun jdk1.3 does not implement MIDI IN. Alternatives are:
</para>
<ItemizedList>
<ListItem><para><ulink url="http://www.softsynth.com/javamidi/">JavaMIDI</ulink> by Robert Marsanyi</para></ListItem>
<ListItem><para><ulink url="http://www.bonneville.nl/software/Wire/">Wire</ulink> by Niels Gorisse</para></ListItem>
<ListItem><para>MidiPort by Jörg
Prante. [TODO: URL]</para></ListItem>
</ItemizedList>
<para>Each of this is a simple library written for
Windows.</para>
<para>Tritonus has an almost complete MIDI implementation. If
you are running Linux, just install Tritonus. I you are using
Windows95/98, there is an experimental add-on to the Sun jdk1.3
that can be installed with the Sun jdk1.3. <ulink
url="http://rupert.informatik.uni-stuttgart.de/~pfistere/tritonus-midishare-win.zip">Download</ulink>
it. (Matthias)</para>
<sect2><title>I have unstable timing when playing back MIDI
notes</title>
<para>Java Sounds synthesizer is a virtual synthesizer - it uses
your soundcard's audio out and creates the sounds in
software. That is why there is a delay: audio data is quite huge
compared to midi data (e.g. 5 bytes compared to 88200 bytes for
one note). Audio data is put in blocks of a number of samples to
the soundcard. When the blocks are 23ms long, you have at least
23 ms delay. Another source of delay comes from moving these
data to the soundcard. Better soundcards, and especially PCI
soundcards can do the memory transfer very fast. There is also
more software overhead for audio data - obviously it takes more
time to calculate and treat audio data than MIDI data.</para>
<para>I cannot give an authoritative answer to the problem, why
the delay changes. It may be due to a block-wise implementation
of the internal Java Sound synthesizer: as the audio data is
always pushed in blocks to the soundcard, it may be that MIDI
events are always synthesized from the start of a block. (I just
wrote (for testing purposes) a drum machine that works like
this). This results in unequal delay. I am not sure about this
"theory", as playing a midi file seems to have perfect
timing (i.e. midi notes may start inside a block). Let's see
whether the programmers of the synthesizer engine
respond. (Florian)</para>
<sect1><title>Java Sound in Applets</title>
<!--
<sect2><title>
I want to record sound in an applet. Is this possible?
</title>
-->
<sect2><title>
I heared that signing applets is needed to record sound. Is this true?
</title>
<para>
Almost true.
</para>
<sect1><title>Performance issues</title>
<sect2><title>Is it possible to apply an FFT transform in real
time under Java ?</title>
<para>At least for JIT compilers, Java is very fast (under
certain conditions it reaches or tops C++ performance!) - and I
think even on no-JIT compilers, FFT analysis is no problem in
real time, of course depending on available processor power and
resources. (Florian)</para>
<sect2><title>How do I reduce latency - or- I want to record sound
and simultaneously play it back without delay</title>
<para>You'll never be able to completely remove latency. Digital
audio on computers is processed in "chunks", i.e. a
small number of samples. When recording, you have to wait until
one chunk is filled, then it gets passed to your application. So
there is a minimum delay of the time of a chunk latency for
recording. For playback the same "problem": the
soundcard gets chunks from the application, so when one chunk is
passed, the soundcard starts playing with the first sample of
the chunk and it takes the time of the chunk that the last
samples has been played. So, for playback you'll get the same
delay. Added to that, the software (i.e. the different hardware
layers copying chunks, etc.) and the hardware (hardware latency)
add to the total delay.</para>
<para>There are approaches like DirectSound, ASIO or Alsa that
all try to minimize the software part's latency and to allow
very small chunks. When used efficiently on high-quality
soundcards, an audio loop is possible with a barely noticeable
delay (e.g. 20ms).</para>
<para>Java Sound (and therefore also JMF) actually adds one
layer to the software part, so latency is slightly increased
compared to native audio applications. You control the chunk
size with the buffer size argument when constructing a
SourceDataLine or TargetDataLine in Java Sound. I don't know
about JMF's concepts. I also experienced some problems with
Java Sound recording when using small buffers (like 1024 samples
at 44KHz). (Florian)</para>
<sect2><title>I want to provide successive multi track recording:
I record new channels while playing back all previously recorded
channels. However, I get synchronization problems, there are
different delays</title>
<para>The delay, of when the data arrives regarded to when you
started recording, should be quite fixed. However, recording and
playback may have different delays. The delays depend on the
soundcard, the operating system (including the sound card
drivers) and the implementation of Java Sound you use (and also
a bit on what JDK you use).</para>
<para>Also, the Java Sound API does not provide means for
querying the device's latency. This would be quite difficult
anyway for the Java Sound subsystem. However, normal soundcards
have very little hardware delay (even the cheap ones), so once
they receive the command to start recording, they really start
it in a matter of some milliseconds - typically 20-30ms. </para>
<para>Using the soundcard via Java Sound, there are many layers
until the data arrives in your program, so some delay is added.
However, I haven't noticed a relevant delay when recording. I
haven't tried to do your approach of measuring the delay,
though.</para>
<para>So what you should is, is to call the start() method both
on TargetDataLine and SourceDataLine "at once" with
the minimum overhead possible. Notice that the buffers of the
recording line arrive when they have been finished recording
(i.e. when the amount of time has been elapsed), while playback
lines need a buffer prior that they are played. This may not be
obvious at first. So when you do record and playback at once,
the first received block from the recording line corresponds in
time to the first played buffer (which has been submitted right
with "start").</para>
<para>For playback of the 2 files, you should not use 2 playback
lines, but mix them from your program. Like that, you can at
least control the exact sample-delay of the 2 playback lines and
adjust it (probably only possible by ear).</para>
<para>These are handmade solutions. The "real"
solution is to make use of Mixer.synchronize. This is the
proposed solution to your problem from the Java Sound API. Like
that you can synchronize the recording line and the playback
line - or the 2 playback lines. However, it seems that it isn't
implemented in current versions of Java Sound (although I
haven't tested it). (Florian)</para>
<sect1><title>Other resources</title>
<sect2><title>I'm looking for books on Java Sound.</title>
<para>There are currently no books on Java Sound.
There is a book covering some DSP algorithms in Java:
</para>
<ItemizedList>
<ListItem><para>'Digital Audio with Java' by Craig A. Lindley</para></ListItem>
</ItemizedList>
<para>
[TODO: JMF books] (Matthias)
</para>
<sect2><title>
Where can I find information on the Java Sound API?
</title>
<para>
Look at <ulink url="http://java.sun.com/products/java-media/sound/">http://java.sun.com/products/java-media/sound/</ulink>. (Matthias)
</para>
<sect2><title>
Where can I find information on JMF (the Java Media Framework)?
</title>
<para>
Look at <ulink url="http://java.sun.com/products/java-media/jmf">http://java.sun.com/products/java-media/jmf</ulink>. (Matthias)
</para>
<sect2><title>
What mail lists are relevent to Java Sound?
</title>
<para>
JAVASOUND-INTEREST@JAVA.SUN.COM
To subscribe, send email to
listserv@java.sun.com containing the following line in the message
body (NOT in the subject line!): signon javasound-interest
</para>
<sect2><title>What newsgroups are relevent to Java Sound?</title>
<para>There is no newsgroup devoted to Java Sound, but these
might help:
<ItemizedList>
<ListItem><para>comp.lang.java</para></ListItem>
<ListItem><para>comp.lang.java.programmer</para></ListItem>
<ListItem><para>comp.music.midi</para></ListItem>
<ListItem><para>comp.sys.ibm.pc.soundcard.music</para></ListItem>
<ListItem><para>comp.sys.ibm.pc.soundcard.tech</para></ListItem>
<ListItem><para>comp.sys.ibm.pc.soundcard.* where '*' is your favorite soundcard maker</para></ListItem>
</ItemizedList>
</para>
<sect1><title>Digital audio basics</title>
<sect2><title>What is endianess/big endian/little endian?</title>
<para>Most common computers have their memory organized in units
of 8 bits, called a byte. The bytes can be adressed by ordinal
numbers, starting with zero. (The harware organization of the
memory is often in rows of 16, 32, 64, 128 or even more
bits. But the instruction set of the processor still gives you
the view of the byte-organized memory.) If you want to store a
value that needs more than 8 bits, the question arises how the
bits of the value are divided in bytes and stored in memory. If
you have have a value with 16 bits, there is not much discussion
that it has to be divided into two groups: bit 0 to 7 and bits 8
to 15. But then, the fight starts. Some CPUs store the first
group (bit 0 to 7) in the byte with the lower address and the
second group (bits 8 to 15) in the byte with the higher
address. This schema is called little-endian. As an example, all
Intel CPUs are little-endian. Other types of CPUs do it the
other way round, which is called big-endian. Sparc and PowerPC
(Motorola) CPUs are big-endian. (Matthias)</para>
<sect1><title>Misc</title>
<sect2><title>My Java Sound program does not exit when leaving the
main() method</title>
<para>By default, the java virtual machine terminates when all
threads have terminated and the main function has also been
exited. It seems that Java Sound's audio subsystem creates
threads which remain, so you have to call explicitely
System.exit(int). (Florian)</para>
<sect2><title>I installed Tritonus on a Sun jdk1.3.0 and I still
get the behaviour of Sun's Java Sound implementation.</title>
<para>Using Tritonus under jdk1.3.0 is a bit tricky. The point
is that by installing Tritonus you are just adding Tritonus'
mixers, converters and other service providers to the ones of Sun's
Java Sound implementation. Especially, Sun's mixing engine is
still the default mixer. To use Tritonus' mixers, you have to
select the mixer in your program manually: get the respective
Mixer object from AudioSystem, and allocate the lines from this
Mixer object. The same is true for MidiDevices. It's possible
to use Tritonus' javax.sound.* classes by putting them into the
boot classpath *before* rt.jar. But this still leaves you with
Sun's service providers. Getting rid of them required to change
the service provider configuration files inside rt.jar or other,
even more fancy measures. The alternative way out of the hell is
to use a jdk1.2.X, where Tritonus is the only Java Sound
implementation. (Matthias)</para>
<sect2><title>I tried to compile AudioPlayer (or another program
from the Java Sound Examples). I get errors about
gnu.getopt.Getopt not being available.</title>
<para>Download <ulink
url="http://www.urbanophile.com/arenn/hacking/download.html">GNU
getopt</ulink> and install it. Alternatively, there are
simplified versions of some examples that do not use GNU getopt
(For instance, SimpleAudioPlayer instead of AudioPlayer).
(Matthias)</para>
<sect2><title>I want to have a simple test if Java Sound is
available</title>
<para>Try that:</para>
<pre>public static boolean JavaSoundInstalled() {
boolean result=false;
try
{
result = javax.sound.sampled.AudioSystem.getMixerInfo().length > 0;
} catch (Throwable t) {}
}
</pre>
<para>(Florian)</para>
<sect2><title>I want to use com.sun.* classes. Is there any
documentation ?</title>
<para>No, and it is strongly advised to not use them: these are
internal classes of the specific implementation, and in other
JVM's or even in future JVM's from Sun they may not be
present. (Florian)</para>
<sect2><title>I want to play a wave file in an JDK1.1.x
applet</title>
<para>First of all, JDK1.1 generally only provides µ-law, 8000Hz mono
playback. It does not provide wave file playback directly. And
for playback of audio data of the application, there are only
the "unofficial" sun.audio.* classes. So you'd need to
write your own classes that read in the wave files, convert the
sound data to ulaw and then use the sun.audio.* classes to play
them. For code that parses wav files and does ulaw conversion
look at tritonus' source code: <ulink
url="http://cvs.sourceforge.net/cgi-bin/cvsweb.cgi/tritonus/src/org/tritonus/sampled/file/?cvsroot=tritonus">http://cvs.sourceforge.net/cgi-bin/cvsweb.cgi/tritonus/src/org/tritonus/sampled/file/?cvsroot=tritonus</ulink>
(WaveAudioFileReader.java) and <ulink
url="http://cvs.sourceforge.net/cgi-bin/cvsweb.cgi/tritonus/src/org/tritonus/sampled/?cvsroot=tritonus">http://cvs.sourceforge.net/cgi-bin/cvsweb.cgi/tritonus/src/org/tritonus/sampled/?cvsroot=tritonus</ulink>
(TConversionTool.java). Click on the version number to see the
source code. Tritonus classes are under the LGPL licence.</para>
<para>Regarding sun.audio.* classes: it is discouraged to use
them. I heard that they don't work anymore as expected in
jdk1.3. My applets using them work well from jdk1.0 to jdk1.1
and in all browsers that I could put my hand
on. (Florian)</para>
<sect2><title>When I call AudioSystem.getAudioFileTypes(), I
receive an empty array. What's wrong?</title>
<para>This is a bug in the Sun jdk1.3.0. It always returns an
empty array if there are no service provider plug-ins. If you
have service provider plug-ins installed, it returns only the
types supported by the plugins, not the "built-in" ones. The
Tritonus implementation of this method works as
expected. (Matthias)</para>
<sect2><title>I want to use Mixer.synchronize(), but it seems to have no effect.</title>
<para>Synchronization isn't implemented in any known Java Sound implementation. It is on my TODO list for Tritonus. (Matthias)</para>
<!--h3>
When I try to run Player, I get the exception...
</h3-->
<!--h3>
I want to contribute to Tritonus. What can I do?
</h3-->
<!--h3>
I want to stream sound over a network. Can I do this with Java Sound?
</h3-->
</article>
distrib
>
Fedora
>
14
>
x86_64
>
media
>
updates
>
by-pkgid
>
ca54ded59b0fde76a90d33c2ad8033e0
>
files
>
44
