jack-audio-connection-kit (1:0.124.1+20140122git5013bed0-1) unstable; urgency=low
RELEASE NOTES from Paul Davis:
------------------------------
One of the "minor" bug fixes will make a huge difference for some users: if
a particular JACK client crashes only the misbehaving client will be
"zombified" - other clients will continue functioning normally (after a
short delay). If you are developing JACK applications, this can make a huge
difference to your day-to-day experience of JACK 1. The Metadata API
It is now possible to define arbitrary metadata to be associated with any
JACK port or JACK client. This API lays the groundwork for more useful
naming of ports and clients (particularly those associated with hardware),
as well as many other features that developers have talked about in a JACK
context for several years. The full docs on the API can be found here and
there is also a man page for jack_property, which is the primary command
line tool for setting, removing and changing metadata. A short tutorial on
using the Metadata API is available.
Builtin MIDI hardware I/O (on Linux)
For years, we have known that the performance of the -X seq and -X raw
options to the ALSA backend have left much to be desired. For that reason,
most users have been instructed to use a2jmidid (typically with the -e flag
to tell it use external (hardware) MIDI devices). Although a2jmidid
provided good MIDI I/O, it has two problems:
Requires starting an addition program in order to get MIDI I/O via hardware working
Adds latency to the MIDI I/O "through" or "monitor" signal pathway
This release of JACK 1 sees the transformation of a2jmidid into a "slave"
driver that can be started as a part of JACK, much like the old -X seq and
-X raw options. This not only removes the need to start a separate program,
but also reduces the "through" or "monitoring" latency of MIDI I/O by 1
JACK period.
The canonical way to invoke this new internal MIDI driver is with -X
alsa_midi, which will create JACK ports for all MIDI devices (and other
MIDI applications) known to ALSA at the time that JACK starts up. Note that
the new internal driver does not currently notice the arrival or departure
of MIDI hardware or applications, but future improvements will correct
this.
In addition, the old -X seq and -X raw implementations have been removed.
However, using -X seq will be interpreted as a request to use the new
internal MIDI driver, and so is formally equivalent to using -X alsa_midi.
Note that -X seq is an argument to the ALSA backend, and so comes after the
backend specification; by contrast, -X alsa_midi is a server argument, and
must come before the backend specification.
It is worth noting that the server argument -X alsa_midi can be used with
any Linux-based backend (ALSA, OSS, Dummy, Netjack) to get the ALSA MIDI
bridge functional.
Builtin Internal Client for using additional ALSA devices
Older versions of JACK have come with the tools alsa_in and alsa_out which
can be used to add additional ALSA supported audio devices to a running
JACK setup. These tools work quite well, but:
Fons Adriennsen developed significantly better versions known as
zita-a2j and zita-j2a that use his own resampler. these tools are (like
the rest of the JACK tools) separate programs that the user must start
up after the server is running
To address these two points, the zita-a2j/zita-j2a code has been merged
into the tools part of JACK as a pair of internal clients ("zalsa_in" and
"zalsa_out") that can be specified on the command line. So for example,
this JACK command line:
jackd ... -I "USB Mic:zalsa_in/-dhw:USB,-r44100,-n2,-p512" ...
will create an internal client called "USB Mic" that represents the ALSA
device "hw:USB" using the ZITA alsa/jack bridge code, running at 44100kHz,
with 2 periods of size 512. If you do not specify the period size or sample
rate, then the values in use by the backend will be adopted. Audio being
captured or played back via devices added to JACK in this way will be
resampled with substantial accuracy and quality.
Note that the -I argument has been present in JACK 2 for sometime, but the
new JACK1 implementation extends the semantics of its argument by allowing
the user to specify a client name as well as arguments for the internal
client code.
Both internal clients (zalsa_in and zalsa_out) will accept the -h argument
to show their possible arguments: jackd -I zalsa_in/-h -d alsa (the final
-d alsa is required by JACK but not used in this case). The arguments will
match those of the standalone zita-a2j and zita-j2a (external) clients.
Since this new "multiple device" capability is implemented using JACK
internal clients, you can remove a given device by just unloading the
client using the long-existing but rarely used jack_unload command.
Similarly, if you wanted to add a device to a running server after it has
started, jack_load can be used for that.
It is worth noting that these internal clients can be used with any
Linux-based backend (ALSA, FFADO, OSS, Dummy, Netjack) to add additional
ALSA-support devices to an instance of JACK.
Syntactic Sugar Version
To make the addition of extra audio devices to an instance of JACK even
easier, JACK 1 also features the new -A option which takes almost nothing
more than an ALSA card name (e.g. "SB", "DSP", "Codec", "HDMI" and many
others) and makes the device available for playback or capture or both.
Adding %p or %c to the card name limits the direction of audio flow.
This option does nothing more than translate its argument into an equivalent use of -I, so for example:
-A SB
is equivalent to using both of these arguments:
-I SB/zalsa_in/-dhw:SB
-I SB/zalsa_out/-dhw:SB
As with -I, the -A argument may be used multiple times to add as many
devices as you want. -A is simple but not very powerful - if you need to
provide more options (e.g. to adjust I/O latency values), then you must use
the -I argument instead.
Finally, note that these internal clients are theoretically compatible with
JACK 2, and should work with that implementation of JACK once JACK 2 has a
working internal client loading mechanism restored.
-- Adrian Knoth <adi@drcomp.erfurt.thur.de> Wed, 22 Jan 2014 22:17:27 +0100
jack-audio-connection-kit (1.9.4+svn3842-1) unstable; urgency=low
/etc/init.d/jackd has been removed.
Former jackd packages provided an initscript to start jackd at
boottime, however, this mode is discouraged by upstream and was
therefore dropped in jack-audio-connection-kit-0.116.2+svn3592-2.
See #565117 (and #527642) for more information.
-- Adrian Knoth <adi@drcomp.erfurt.thur.de> Thu, 14 Jan 2010 12:06:57 +0100
jack-audio-connection-kit (0.118+svn3796-1) unstable; urgency=low
Upstream has replaced -L by -r, so in order to disable realtime mode,
specify -r or --no-realtime now. The reason is to have the same
commandline args for jackd1 and jackd2, but -L was already in use
by jackd2.
-- Adrian Knoth <adi@drcomp.erfurt.thur.de> Wed, 18 Nov 2009 10:16:27 +0100
jack-audio-connection-kit (0.116.2+svn3592-3) unstable; urgency=low
The default operation mode for jackd is now realtime mode, upstream has
changed the semantics.
It's no longer necessary to specify -R or --realtime.
If you just run jackd without POSIX realtime priorities (use
'dpkg-reconfigure -phigh jackd' to enable or disable, ulimit -r -l to
check), then jackd will complain. If so, use -L to disable realtime mode.
IOW: If you don't want to run jackd with realtime priorities, you would now
have to provide -L, whereas the formerly optional -R is now the default.
-- Adrian Knoth <adi@drcomp.erfurt.thur.de> Tue, 11 Aug 2009 14:53:02 +0200