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Darwin/MacOSX port for Jack : architecture changes in the implementation
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========================================================================
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gcc 2.95.x or 3.x, the standard OSX 10.3 gcc-3.3 compiler works fine
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MacOSX10.3 SDK package
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libtool >= 1.5 (to build from CVS)
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pkg-config >= 0.15.0 (to build from CVS)
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doxygen (to build documentation)
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libsndfile >= 1.0.0 (for some example-clients)
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GNU readline (for some example-clients)
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All non-Apple tools are available from `fink' or `darwinports'.
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Since fink is not well-integrated with OS X, you must define a bunch
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of environment variables...
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export ACLOCAL_FLAGS="-I /sw/share/aclocal"
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export CFLAGS="-I/sw/include"
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export CPPFLAGS=$CFLAGS
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export LDFLAGS="-L/sw/lib"
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export PKG_CONFIG_PATH="/sw/lib/pkgconfig:/usr/lib/pkgconfig:/usr/local/lib/pkgconfig:/opt/local/lib/pkgconfig"
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The system V shared memory is not very reliable on Darwin/MacOSX, so
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POSIX shared memory API is the preferred default. To override, use...
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./configure --disable-posix-shm
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Jack server audio cycle
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========================
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On Linux, the jack server audio cycle (jack_run_cycle function) is
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called in a real-time SCHED_FIFO thread. On Darwin/MacOSX, the
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jack_run_cycle is directly called inside the CoreAudio audio callback.
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External client activation
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===========================
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Jack Linux implementation use system fifo/pipe to trigger the clients
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real-time callback from the server : the first client of an external
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subgraph is triggered, does it's job and wakes up the next one in the
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list, and so on until the last client that wakes up the Jack
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server. This avoid uneeded context switches between the server and
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clients and thus is more efficient.
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This Linux implementation works also on Darwin/MacOSX but is not very
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efficient : audio gliches occur quite frequently.
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A more efficient system for external client activation has been
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developed. It use low-level mach messages system to implement fast IPC
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between the Jack server and the running clients. The Darwin/MacOSX has
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a very efficient Remote Procedure Call (RPC) implementation that can
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be used: the Jack server activate each external client in turn in a
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On the client side, each client uses an additionnal thread only used
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for the real-time process callback, that will be triggered by the Jack
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server using this fast RPC mechanism.
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The Darwin/MacOSX system use a special class of scheduling for
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Since the server audio cycle is called directly from the CoreAudio
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callback, there is nothing special to do on the server side. On the
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client side, the thread used to call the "process" callback from the
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server is made real-time, using the mach thread API.
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Compilation and installation
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=============================
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- In the jack/jack folder, you'll have to produce the version.h
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manually from the version.h.in file ): Edit the version.h.in, replace
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the JACK_PROTOCOL_VERSION value with the one found in configure.in and
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save as a new version.h file. You should get something like "#define
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jack_protocol_version 6" in the file.
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Several packages need to be installed before compiling Jack :
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- Fink dlcompat (fink.sourceforge.net) : this package define the
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dlopen, dlsym... API used in Jack to load drivers and internal
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clients. The package has to be installed before compiling Jack.
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- fakepoll is a implementation of the poll function using select. The
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Fink version of poll does not work correctly, thus the public domain
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"fakepoll" code has been used instead. It is directly included in the
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Jack Darwin/MacOSX port.
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- PortAudio (www.portaudio.com) : PortAudio is a free, cross platform,
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open-source, audio I/O library. The Jack CoreAudio driver actually is
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implemented using PortAudio. The PortAudio source code for MacOSX has
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to be installed and compiled to produce a framework called
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"PortAudio.framework" that will be used in the Jack link phase.
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Several targets are available in the Project Builder project :
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- jackd : build the Jack server ("jackd" executable)
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- jack framework : build the "Jack.framework" library.
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- driver : build the PortAudio driver as a "jack_portaudio.so" shared library.
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- jack_metro : build the "jack_metro" executable.
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- jack_lsp : build the "jack_lsp" executable.
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- jack_connect : build the "jack_connect" executable.
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- jack_disconnect : build the "jack_disconnect" executable.
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Server, driver and library installation :
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-----------------------------------------
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First copy the Jack.framework in /Library/Framework. Then as root :
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# cp jack_portaudio /usr/local/lib
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# cp jackd /usr/local/bin
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Launching Jack server :
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-----------------------
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By default buffer size is 128 frames and sample rate is 44100.
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$ jackd -v -R -d coreaudio
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To setup a 32 frames buffer and a 4800 Hz sample rate :
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$ jackd -v -R -d coreaudio -p 32 -r 48000
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The Darwin/MacOSX implementation is quite efficient: on a G4/867 Mhz,
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the Jack server can run with a 32 frames buffer size without noticable
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Known problems or unimplemented features
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=========================================
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- thread cancellation : the pthread API pthread_cancel is not
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completely available on Darwin/MacOSX. Thread cannot be cancelled in
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the general case: they must use explicit cancelation points like
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"pthread_testcancel" (see the "jack_client_thread" function)
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- xruns detection and report: not implemented.
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Possible improvements
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======================
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- The audio driver is built on top of PortAudio. It may be more
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efficient to directly use the CoreAudio API in order to avoid
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additional buffer copy and interleaving/disinterleaving operations.
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- The project uses Project Builder. It would be helpful to work on
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the autoconf and automake tools as the Linux version. In this case,
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the macosx/config.h file would have to be removed and generated by
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configure, and jack/version.h will be generated automatically from
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- Better separation of Linux and Darwin/MacOSX only code.
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The Jack port for Darwin/MacOSX version has be done by:
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Grame Research Laboratory
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9, rue du Garet 69001 Lyon - France
added
removed
config/os/macosx/README
