[LAA] [ANN] jack_capture V0.9.40

Kjetil S. Matheussen k.s.matheussen at notam02.no
Tue Jan 26 05:19:13 EST 2010

(I don't agree about the linux-audio-* mailing list
announcement policy, so from now on, program announcements
will only be posted to linux-audio-announce at lists.linuxaudio.org !)

Download from

jack_capture is a program for recording soundfiles with jack.

The default operation of the program is executed by writing "jack_capture"
in the terminal without any extra command line options:

    $ jack_capture

...which will record what you hear in your loudspeakers
into a stereo wav file.

Most important new features since 0.9.36
* Direct support for mp3 using liblame.
* Console cleanup. Terminal should not be messy
   when quitting jack_capture.
* Better buffering schemes.
* Less used memory.

* Autogenerated filenames are unique and humanly readable.

* The 4GB size barrier for wav files is handled by continuing
   writing to new files when reaching 4GB.

* Supports all soundfile formats supported by sndfile.
   (wav, aiff, ogg, flac, wavex, au, etc.)       (option: -f <format>)

* Supports mp3 by using liblame.                (option: -mp3)

* Option for writing raw 16 bit data to stdout. (option: -ws)

* Built-in console meter, plus option for automatically starting
   and stopping the Meterbridge jack meter program. Port
   connections to Meterbridge are done automatically, and
   on the fly, by jack_capture.

* jack_capture can connect to any input or output jack port.

   When "connecting" to a jack input port (i.e. a writable
   port), jack_capture constantly monitors which jack ports
   which are connected to the input port, and make sure
   jack_capture is always connected to the same ports.

   In other words, jack_capture will reconnect its ports
   automatically during recording to match the connections
   of the ports. This is for instance convenient when
   recording the playback ports since jack_capture can be
   started first, and then other programs can start and
   stop at any moment while all sound still should be recorded.

* No limit on the number of jack ports jack_capture can connect to.
   (I.e. the --port argument can be specified more than once, plus
   that it accepts wildcard arguments. For instance,

        jack_capture --port "*"

   will connect to all current jack ports, both input and output
   ports, except jack_capture's own ports.)

* Buffers are automatically increased during runtime to prevent
   underruns and to avoid wasting memory by preallocating too much.
   (handled by using lockless atomic fifo/lifo queues to store
   temporary sound data instead of ringbuffers)

* The disk thread is automatically reniced to a higher priority when
   using more than half of the buffer.

* Significantly better recording performance than Ardour.
   (probably because jack_capture writes all channels into
   only one file and that it is not creating peak files).
   (tested on athlonXP)

* No problem writing at least 256 channels of 32 bit wav at once to a
   local hard drive. (tested on icore7)

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