A program for recording soundfiles with jack
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jack_capture V0.9.73
Released 2017-05-19
Kjetil S. Matheussen

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.

Other features:

* 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 that input port, and makes 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.

* 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)

$ jack_capture

jack_capture  [--bitdepth n] [--channels n] [--port port] [filename]
              [ -b        n] [ -c        n] [ -p    port]

"bitdepth" is by default FLOAT. It can be set to either 8, 16, 24 or 32. (for relevant formats)
"channels" is by default 2.
"port"     is by default set to the two first physical outputs. The "port" argument can be
           specified more than once.
"filename" is by default autogenerated to "jack_capture_<number>.<format>"
           Beware that you might risk overwriting an old file by using this option.
           By not using this option, you will not overwrite an old file.
           See also the option --filename-prefix

Additional arguments:
[--recording-time n] or [-d n]   -> Recording is stopped after "n" seconds.
                                    This options also starts jack_capture in --no-stdin mode.
                                    To stop recording before the timeout, one can press Ctrl-C.)
[--filename-prefix s]/[-fp n]    -> Sets first part of the autogenerated filename.
                                    (default is "jack_capture_")
[--leading-zeros n] or [-z n]    -> "n" is the number of zeros to in the autogenerated filename.
                                    (-z 2 -> jack_capture_001.wav, and so on.) (default is 1)
[--format format] or [-f format] -> Selects fileformat provided by libsndfile.
                                    See http://www.mega-nerd.com/libsndfile/api.html#open
                                    (Default is wav for 1 or 2 channels, and wavex for more than 2.)
[--print-formats] or [-pf]       -> Prints all sound formats provided to sndfile to screen and then
[--version] or [-v]              -> Prints out version.
[--silent] or [-s]               -> Suppresses some common messages printed to the terminal.
[--absolutely-silent] or [-as]   -> Suppresses all messages printed to the terminal.
                                    Warning: libraries used by jack_capture may still print messages.
[--verbose] or [-V]              -> Prints some extra information to the terminal.
[--mp3] or [-mp3]                -> Writes to an mp3 file using liblame (LAME).
                                    (the --format option has no effect using this option)
[--mp3-quality n] or [-mp3q n]   -> Selects mp3 quality provided by liblame. n=0 is best, n=9 is worst.
                                    Default n is 2. (0 uses the most amount of CPU, 9 uses the least)
[--mp3-bitrate n] or [-mp3b n]   -> Selects mp3 bitrate (in kbit/s).
                                    Default is set by liblame. (currently 128)
[--write-to-stdout] or [-ws]     -> Writes 16 bit little endian to stdout. (the --format option, the
                                    --mp3 option, and some others have no effect using this option)
[--disable-meter] or [-dm]       -> Disable console meter.
[--hide-buffer-usage] or [-hbu]  -> Disable buffer usage updates in the console.
[--disable-console] or [-dc]     -> Disable console updates. Same as "-dm -hbu".
[--no-stdin] or [-ns]            -> Don't read the console. (i.e pressing return won't stop recording.)
[--daemon]                       -> Same as writing "--no-stdin --absolutely-silent".
[--linear-meter] or [-lm]        -> Use linear scale for the console meter (default is dB scale)
[--dB-meter-reference or [-dBr]  -> Specify reference level for dB meter. (default=0)
[--meterbridge] or [-mb]         -> Start up meterbridge to monitor recorded sound.
[--meterbridge-type] or [-mt]    -> Specify type. vu (default), ppm, dpm, jf or sco.
[--meterbridge-reference]/[-mr]  -> Specify reference level for meterbidge.
[--jack-transport]/[-jt]         -> Start program, but do not start recording until jack transport has started rolling
                                    When jack transport stops, the recording is also stopped, and the program ends.
[--jack-transport-multi]/[-jtm]  -> Similar to --jack-transport, but do not end program when jack transport stops.
                                    Instead, record to a new file when jack_transport starts rolling again.
                                    (not implemented yet)
[--jack-freewheeling]/[-jf]      -> Start program, but do not start recording until jack enters freewheeling mode
                                    When jack leaves freewheeling, the recording is also stopped, and the program ends.
[--manual-connections]/[-mc]     -> jack_capture will not connect any ports for you. 
[--bufsize s] or [-B s]          -> Initial/minimum buffer size in seconds. Default is 8 seconds
                                    for mp3 files, and 4 seconds for all other formats.
[--maxbufsize] or [-MB]          -> Maximum buffer size in seconds jack_capture will allocate.
                                    Default is 40. (Buffer is automatically increased during
                                    recording when needed. But it will never go beyond this size.)
[--filename] or [-fn]            -> Specify filename.
                                    Beware that you might risk overwriting an old file by using this option.
                                    To only set prefix, use --filename-prefix / -fp instead.
                                    (It's usually easier to set last argument instead of using this option)
[--osc] or [-O]                  -> Specify OSC port number to listen on. see --help-osc
[--timestamp] or [-S]            -> create a FILENAME.tme file for each recording, storing
                                    the system-time corresponding to the first audio sample.
[--rotatefile N] or [-Rf N]      -> force rotate files every N audio-frames.
[--hook-open c] or [-Ho c]       -> command to execute on successful file-open. (see below)
[--hook-close c] or [-Hc c]      -> command to execute when closing the session. (see below)
[--hook-rotate c] or [-Hr c]     -> command to execute on file-name-rotation. (see below)
[--hook-timing c] or [-Ht c]     -> callback when first audio frame is received. (see below)
[--timemachine] or [-tm]         -> jack_capture operates in "timemachine" mode.
[--timemachine-prebuffer s]      -> Specify (in seconds) how long time to prebuffer in timemachine mode.
[ -tmpb s]                       -> ------------------------ "" ----------------------------------------

 All hook options take a full-path to an executable as argument.
 The commands are executed in a fire-and-forget style upon internal events.
 All output of the hooks is discarded.
 Paramaters passed to the hook-scripts:
  open:   CMD <filename>
  close:  CMD <filename> <xrun-count> <io-error-count>
  rotate: CMD <filename> <xrun-count> <io-error-count> <new-filename> <seq-number>
  timing: CMD <filename> <time-sec> <time-nses> <jack-port-latency in frames>


To record a stereo file of what you hear:

To record a stereo file of what you hear in the flac format:
 $jack_capture -f flac

To record a stereo file of what you hear in the ogg format:
 $jack_capture -f ogg

To record a stereo file of what you hear in the mp3 format:
 $jack_capture -mp3

To record a stereo file of what you hear in the wav format:
  $jack_capture --port system:playback_1 --port system:playback_2
**** NOTE! The above example does _exactly_ the same as the default!!!  ****

Same result as above, but using a different syntax:
  $jack_capture --channels 2 --port system:playback*

To record the output from jamin:
  $jack_capture --port jamin:out* sound_from_jamin.wav

To record all sound coming in to jamin:
  $jack_capture --port jamin:in* sound_to_jamin.wav

To record all sound coming in and out of jamin:
  $jack_capture --port jamin* sound_to_and_from_jamin.wav

To record a stereo file from the soundcard:
  $jack_capture -c 2 -p system:capture*

Originally based on the jackrec program in the jack distribution
made by Paul Davis and Jack O'Quin. Not much left of that code now.

Peak indicator code for the console meter taken
from meterbridge by Steve Harris.

Code for writing to stdout was made by looking at http://mir.dnsalias.com/oss/jackstdout/start
made by Robin Gareus.

Code contributions from:
Florian Faber, Robin Gareus, Adrian Knoth, Filipe Lopes, Svend-Erik Kjær Madsen (made jack_capture_gui),
Hermann Meyer (made jack_capture_gui2), Dan Muresan, Orcan Ogetbil, and Alessio Treglia.

Thanks to the following for helping to fix bugs, report bugs, give suggestions, etc.:
Fons Adriaensen, Gabriel J.L. Beckers, Julien Claassen, Dominique Fober, Peder Hedlund,
Cesare Marilungo, Jaromír Mike¨, Dragan Noveski, Andras Simon, and Anders Vinjar.

0.9.72 -> 0.9.73
* Update version to 0.9.73. (Version number was set to 0.9.71 in 0.9.72.)
* Make it clearer that you risk overwriting an old file by specifying filename
* OSX compilation fix (Julius Smith)

0.9.71 -> 0.9.72
 * Print warning in case user overwrites existing file.
 * Use execvp, not execv. Also print strerror() if execvp failed.
 * Support OSX (Luciano Iammarino)
 * Some tsan fixes
 * replace static .wav suffix with correct soundfile_format (Sebastian Reimers)
 * Silence unused parameter warnings from gcc 4.8
 * Warn about unable to set SCHED_OTHER process using setpriority(), not a SCHED_FIFO process
 * Compilation patches from debian

0.7.70 -> 0.9.71
 * Dont limit mp3 files to stereo only
 * Flush mp3 files before closing

0.9.69 -> 0.9.70
 * notify user about jack x-runs that occurred during recording (Robin Gareus)
 * Include timemachine documentation in README file

0.9.67 -> 0.6.69
 * Timemachine mode. Make jack_capture work like Steve Harries timemachine recorder
   Enable with the -tm / --timemachine option. Set prebuffer time with the -tmpb / --timemachine-prebuffer option.
   (With help from Robin Gareus)
 * OSC methods to control time-machine mode. (Robin Gareus)
 * Check if the call to sem_wait failed. Do not stop recording if so.
 * Fix reset-colour. (Robin Gareus)
 * Use jack_free to free port name array, not free. 
 * Set mono/24bit the default format for SDS files.

0.9.66 -> 0.9.67
 * osc_help must be available, even without HAVE_LIBLO
 * fix for signed / unsigned integer comparison

0.9.65 -> 0.9.66
 * Respect both DESTDIR and PREFIX. (Robin Gareus)

0.9.64 -> 0.9.65
 * Fix for jack_capture_gui console printing.

0.9.63 -> 0.9.64
 * Add necessary -lrt linker flag
 * Change prefix to PREFIX from makefile, and remove DESTDIR
 * Fix the jack_capture_gui script

0.9.62 -> 0.9.63
 * Fix. Swapped --no-stdin and --daemon options

0.9.61 -> 0.9.62
 * CHANGE IN BEHAVIOR: The --daemon option now also suppresses all console message.
 * Support for using a config file.
   A file in the distribution called 'config' can be copied into ~/.jack_capture/config and modifed as needed.
 * Allow to remote-control jack-capture via OSC. (Robin Gareus)
   (see --help-osc)
 * Added exec-hooks: jack_capture can launch an external app in fire&forget mode (from the disk-thread). (Robin Gareus)
    * When it opens a new file for writing
    * When it closes a file, recording finished
    * On file-name-rotation
    * When first audio frame is received.
 * Write a timestamp file with sample-accurate system time of the start of recording. (--timestamp) (Robin Gareus)
 * Forced file-name rotatation every N audio-frames. (--forcerotate) (Robin Gareus)
 * A new option to make jack_capture absolutely silent. (--absolutely-silent) (Robin Gareus)
 * Option for recording only while freewheeling. (--jack-freewheel) (Robin Gareus)
 * Total recorded time shown in console, as minutes and seconds.
 * Backwards compatible JACK latency API. (Robin Gareus)
 * Don't close jack client too early.
 * New option: --no-stdin. Works the same way as the old --daemon option.

0.9.60 -> 0.9.61
 * Fix writing to stdout.
 * Don't use helper thread when writing to stdout.

0.9.59 -> 0.9.60
 * Applied Filipe Lopes' freewheel patch. Do not reconnect ports when

0.9.58 -> 0.9.59
 * Terminal printing looks okay now. (Don't look at the code!)

0.9.57 -> 0.9.58
 * Created git repository for jack_capture at github:
 * Removed jack_capture_gui2 from target list. The source is still
   included with jack_capture, and can be compiled up by writing
   "make jack_capture_gui2", but I'm not willing to maintain it.
   Please use at your own risk. If anyone wants to distribute it
   and maintain it as a program separate from jack_capture,
   please do so.
 * Fix bug which in theory could cause malformed sound data to be 
   sent to stdout.
 * Fix bug that caused longer durations than 2^31 frames to fail
   (when using the --duration switch).
   (Caused by a function returning int instead of int64_t.)
   Thanks to Dan Muresan for pointing out the bug.
 * Added the "-daemon" switch patch from Dan Muresan.
   If the "-daemon" switch is enabled, jack_capture will not read
   from stdin.
 * Added the "-manual-connections" switch. jack_capture will
   not connect any ports for you when this is enabled.

0.9.56 -> 0.9.57
 * Applied gcc 4.5 linking order fix from Alessio Treglia.
 * Changed march=native to mtune=native

0.9.55 -> 0.9.56
 * Fix for possible error when trying to connect to a non-existing port.

0.9.54 -> 0.9.55
 * Don't hardcode meterbridge path during compilation. Thanks to Adrian Knoth
   for fix.
 * Avoid killing random process at exit in case meterbridge couldn't be started.

0.9.53 -> 0.9.54
 * Removed jack_capture_gui from the target list since it uses Xdialog,
   which again belongs to a package requiring gtk1. (This should make
   things simpler for package managers)
 * Made meterbridge optional.

0.9.52 -> 0.53
 * Added the option --filename-prefix / -fp for setting the prefix for
   autogenerated filenames. The default is "jack_capture_".
 * Made jack_capture_gui2 use the -fp option to avoid overwriting files
   from older sessions.
 * Changed jack_capture_gui2 to use "-f ogg" instead of piping through
   oggenc. Did not do the same change for mp3 files, since liblame is
   not always available.
 * Added code to jack_capture_gui2 to create uniqe filenames when creating
   mp3 files.

0.9.51_beta -> 0.9.52
 * Smaller fixes
 * Crashfix for exit handling. (introduced in 0.51_beta)

0.9.50 -> 0.51_beta
 * Smaller reorganizing of buffer handling, disk handling and exit handling.

0.9.49 -> 0.50
 * Only print warning if unable to set nice value less than 0. (-10 is okay now)
 * Added JackPortIsTerminal as jack port flag.
 * Various cleanups.

0.9.48 -> 0.9.49
 * Let the jack process thread trigger the buffer check thread instead of using
 * Added the -jt option to let jack transport trigger when to start and stop recording.

0.9.47 -> 0.9.48
 * Fixed possible bug when finishing the recording if user has specified a duration.
 * When allocating buffer, do not zero it out, only touch all pages belonging to
   it to make sure all memory is mapped into physical memory before it is used
   by the realtime process. This avoids hogging the memory bus unnecessarily.
   The first 8 blocks are still zeroed out during initialization though, for
   the CPU cache. (Might create a less shocking startup.)
 * Push back the '\n' character after reading it from stdin. For some unknown
   reason this seems to fix the occational problem of mixed up characters in
   the console when exiting. (if only ncurses worked in non-fullscreen mode...)

0.9.46 -> 0.9.47
 * Only call sem_post if waiting. In extremely extreme situations, this avoids
   the sem value to overflow. Don't know what happens then.

0.95_beta -> 0.9.46:
 * Smaller cleanups.
 * Reduced chance of cache misses in the buffering scheme.

0.9.44 -> 0.9.45_beta:
 * Replaced the two lockless fifo/lifo queues with three lockless ringbuffers. (CPUs without
   CAS2 instruction are now supported.)
 * Only increase buffer by two blocks at the time between soundcard interrupts. This should
   decrease the chance of jack_capture hogging the memory bus for too long. (Which in theory
   can lower the chance of xruns in memory intensive realtime processes.)
 * Changed buffering incrementing scheme. If, at any time, the amount of free buffer is smaller than
   the initial buffer size, increase the buffer a little bit. Only do this if the buffer is
   less than maxbuffer. Buffer is never decreased.
 * Replaced all posix pthread_cond variables with posix semaphores. Far simpler code and
   much easier to understand.

0.9.43 -> 0.9.44:
 * Increased default buffer time from 4 seconds to 8 seconds for mp3 files.
   (Saw more than 1 second of the buffer was used one time in the start of
    the recording on a very fast machine. Buffer was increased automatically
    as supposed to, but the default init buffer size is increased anyway
    just in case.)

0.9.42 -> 0.9.43:
 * Fixed correct autogenerated file suffix for mp3 files.

0.9.41 -> 0.9.42:
 * Updated --advanced-help option and README file

0.9.40 -> 0.9.41:
 * Added missing link libraries to the makefile. Caused by Fedora not
   supporting indirect linking anymore. Patch from Orcan Ogetbil.
 * Applied patch from Orcan Ogetbil to fix 64 bit PowerPC compilation.

0.9.39 -> 0.9.40:
 * Made "-f mp3" do the same as "-mp3". ("-mp3" still works)

0.9.38 -> 0.9.39:
 * Reduced default buffering time from 10 to 4 seconds. (Buffering time
   can probably safely be set below 1 second with the new buffer monitor
 * Also increase buffer when more than 1/4 of the buffer is used
   and the unused buffer time is less than 5 seconds. (This in addition
   to always increase buffer when more than half of it is used)
 * Fixed console update and keyboard handling.

0.9.37 -> 0.9.38:
 * Added the --mp3-bitrate option.
 * Renamed --lame-quality to --mp3-quality.
 * Use a new dedicated high-priority SCHED_OTHER thread to monitor buffer status.
   Buffer status was previously only checked in the disk thread, but since the
   disk thread might stall for longer periods, it is not an ideal place to do this.
 * Replaced the --help output with a much simpler text, making it clearer that extra
   options are normally not needed. Also added the --advanced-options option, which
   displays the contents of the old --help option.
 * Fix --help a bit

0.9.36 -> 0.9.37:
 * Print warning in case nice value in /etc/security/limits.conf is set
   to -10 instead of -20.
 * Added support for mp3 files. Requires liblame. Not very well tested yet.
   Note that jack_capture also compiles without liblame installed.
   (should be practical for package distributors who can not make
    jack_capture depend on liblame). There is no runtime linking to
   liblame yet though, so mp3 files are not supported unless libmp3lame.so
   + lame/lame.h is installed when jack_capture is compiled.
 * Check whether sndfile supports ogg during compilation. (Avoid having
   to edit the Makefile when using an older version of sndfile)
 * Better screen clean-up at shutdown. (Not working very well yet, maybe
   ncurses should be used instead of manually sending escape sequences?)

0.9.35 -> 0.9.36:
 * Add support for OGG (requires sndlib>=1.0.18)
 * Check if file format is supported by sndlib before creating file
 * Added auto-support for WVE, MPC2K and RF64. (untested)

0.9.34 -> 0.9.35:
 * Reset terminal colors when exiting.
 * Check dependencies for various programs in the Makefile
 * Tried to make it even more clear (if that's possible) that 
   'jack_capture --port system:playback_1 --port system:playback_2'
   does exactly the same as the default.

0.9.33 -> 0.9.34:
 * Added untested patch from Orcan Ogetbil to make jack_capture compile on a ppc64 platform.
   In case jack_capture is ran on a ppc64 platform, a warning is printed during runtime.

0.9.32 -> 0.9.33:
 *Clearing up licenses
 *A fix for open() from Florian Faber.
 *A couple of gui fixes from Orcan Ogetbil.

0.9.31 -> 0.9.32:
 *Changed default format for from wav to wavex for files with more
  than two channels. Thanks to Fons Adriaensen for the suggestion.
 *Added fix for 64 bit mode. Thanks to Andras Simon for helping
  to find the bug and Dominique Fober for fixing the bug.
 *Added the "-verbose" option for easier debugging in case program
  crashes or freezes.
 *Check if sndfile.h exists before generating setformat.c.

0.9.30 -> 0.9.31:
 *Cleaned up exit handling and connection thread startup.
  When recording is stopped, the "Please wait, writing to disk"
  message is visible, and the console is not removed until
  everything is written to disk.

0.9.29 -> 0.9.30:
 *Added Hermann Meyer's jack_capture_gui2 program.
  jack_capture_gui2 is a nice graphical frontend
  for for jack_capture with lots of options.
  Many thanks to Herman for the contribution.

0.9.28 -> 0.9.29:
 *Don't exit in case port is not found.
 *Print runtime warning and error messages on top of the
  console to avoid printing the console meter yet another time.
  (it's much prettier also)

0.9.27 -> 0.9.28:
 *Fixed a bug that could cause (and especially after the switch
  from calloc to my_calloc apparantely) segfault when specifying
  --port more than once. Thanks to Peder Hedlund for spotting
  the bug.
 *Print error instead of segfaulting when a specified jack port
  does not exist.
 *Removed -g option and changed -O0 to -O2. (Oops, don't know
  how long that's been there)

0.9.26 -> 0.9.27:
 *Make sure the stop semaphore is initialized before it might
  be called.

0.9.25-beta -> 0.9.26:
 *Changed the --recording-time / -d option to record exactly the
  correct number of frames. (The format for the option is still
  in seconds though). This fixes the problem where the wall
  clock and the soundcard clock drifts apart.
 *Always increase the buffer size with 2 seconds when more than
  than half the buffer is used, unless maximum buffer size is reached.
 *Added the --maxbufsize / -MB option which sets maximum buffer size.
  Default value is 40 seconds.
 *Decreased the default buffer size from 20 to 10 seconds.

0.9.24-beta -> 0.9.25-beta:
 *Do not use this release!
 *Cleaned up lots of stuff and added support for blocksize change
 *Lots of internal changes:
  Don't use this release for important recordings!

0.9.23 -> 0.9.24-beta:
 *Do not use this release!
 *Changed internal data representation from lockless ringbuffer to
  lockless lifo and fifo stacks. Unmodified lifo/fifo code taken
  from midishare. (Copyright Grame 1999-2005)
 *The code is much prettier now because of the lifo/fifo thing,
  but I haven't looked too much at it yet, so this version
  might very well contain serious bugs which could destroy
  your recording.

0.9.22 -> 0.9.23:
 *Minor spellings
 *Check for out of memory

0.9.22 -> 0.9.22:
 *Clean up source a bit
 *Stop connection thread before closing jack client.
 *Made --help a tiny bit cleaner

0.9.20 -> 0.9.21:
 *Removed shut down code from the SIGINT signal handler.

0.9.19 -> 0.9.20:
 *Fixed segfault in case jack shuts down. Thanks to Julien Claassen
  for reporting the bug.

0.9.18 -> 0.9.19:
 *Do not accept filename starting with "-" when filename is last argument.
 *Added the "--filename"/"-fn" option to set filename not
  as the last argument. Can also contain "-" as first character.
 *Fixed colors a bit and removed a superfluous linebreak.
 *Fixed segfault for missing values in commandline.
 *Manually clear allocated memory instead of using calloc.
 *Removed buffer-info line when recording to stdout.

0.9.17 -> 0.9.18:
 *Removed printing of "continue recording" when writing the last overruns.
 *Niceify the disk writing thread to -20 when more than half the buffer is used.
 *Continously show buffer usage, total number of overruns and whether
  the disk thread has high priority, in the console. Turn off by using 
  the -hdu option.
 *Added option -dc to disable console update. (same as "-dm -hdu")
 *Fancier colors.
 *Removed "hepp".
 *Made dB meter the default and replaced the -dB option with the -lm option.
 *Made the console meter wider to fit the info line at the bottom.

0.9.16 -> 0.9.17:
 *Made sure the process thread won't continue sending
  data when jack_capture is told to quit. This
  lead to race conditions when recording too many channels
  (256 channels on my machine).
 *Added the jack_capture_gui script, based on code
  by Svend-Erik Kjær Madsen.

0.9.15 -> 0.9.16:
 *Replaced sh by bash to make it work in ubuntu.

0.9.14 -> 0.9.15:
 *Fixed exact port name match and gen_setformat. Thanks to
  Gabriel J.L. Beckers for reporting the bugs.

0.9.13 -> 0.9.14:
 *Increased the time the console meter is displayed in red from
  50ms to 2000ms. (when the recorded jack value is equal to or
  higher than 1.0.)
 *Added the -dBr argument to specify reference level when using
  the console dB meter.
 *Added the -mr argument to specify reference level when using
  the meterbridge meter.

0.9.12 -> 0.9.13:
 *Added peak indicators to the console meter. Code to do so taken
  from meterbridge by Steve Harris.
 *Updated --help and README with the new options.

0.9.11 -> 0.9.12:
 *Added option "-mt" to change meterbridge type. Current valid
  options are vu (default), ppm, dpm, jf or sco. It's not necesarry
  to specify "-mb" if using "-mt".
 *Added option "-dB" to get a dB meter for the console meter.

0.9.10 -> 0.9.11:
 *Added examples how to record ogg and mp3 files using the -ws option.
 *Decreased default buffersize from 60 to 20 seconds.
  (I even had trouble provocing underruns using a minimal
   0.05 seconds long buffer, so 60 seconds was obviously overkill)
 *Fixed message and error printing to stderr when
  vu meter is running.

0.9.9 -> 0.9.10:
 *Fixed segfault in case the --channels / -c argument is higher
  than the number of ports which is possible to connect to.
 *Added a terminal vu meter by default. It'll display red
  in case the recorded jack value is equal to or higher than 1.0.
  Use "-dv" to disable.
 *Added the --meterbridge / -mb option, which automatically
  starts Steve Harris' meterbridge (http://plugin.org.uk/meterbridge/)
  and constantly connects them to the same ports as jack_capture
  is connected to.

0.9.8 -> 0.9.9:
 *Added the --write-to-stdout / -ws option which writes 16 bit little endian
  sound to stdout. Code made by looking at jack-stdout.c by Robin Gareus.

0.9.7 -> 0.9.8:
 *Added the --print-formats / -pf option.
 *Replaced jack_client_new() with jack_client_open()

0.9.6 -> 0.9.7:
 *Don't segfault if the opening of a subsequent wav soundfile fails. (ie. if the 4GB limitation
  is reached on the old file and jack_capture continues writing on a new file.)

0.9.5 -> 0.9.6:
 *Fixed so that 2 channels are the default again, as supposed to. (bug was introduced
  in 0.9.4)

0.9.4 -> 0.9.5:
 *Fixed a bug that in some situations can cause segfault when
  jack buffer size is changed while recording.

0.9.3 -> 0.9.4:
 *Fixed bug that caused max 2 channels to be recorded.

0.9.2 -> 0.9.3:
 *Fixed horrible deadlock. Bug found by Ken Restivo.

0.9.1 -> 0.9.2:
 *Fix for a potensional deadlock.
 *Added the --silent/-s argument.
 *Some smaller fixes.

0.9.0 -> 0.9.1:
 *If recording to wav (the default) and the the 4GB limitation is reached,
  automatically close the file and continue writing to a new file with an
  autogenerated name.
 *Added the --version/-v argument.
 *Changed default number of zeros in the autogenerated filename to 1.

0.3.9 -> 0.9.0:
 *Better error output.
 *Autogenerate code to check if various formats are supported by sndlibfile.
 *Bumped version up to 0.9. jack_capture should reach a 1.0 state quite soon.
 *Changed the name of --recording-time to --duration to match -d.

0.3.8 -> 0.3.9:
 *Changed the -rt option name to -d, to be compatible with jackrec.
 *Do not stop recording in case of disk errors.
 *Got rid of deprecated libsndfile functions.
 *Added the --format/-f option. ("jack_capture -f flac", nice :-)  )
  (All sndfile formats are supported: http://www.mega-nerd.com/libsndfile/api.html#open)

0.3.7 -> 0.3.8:
 *Added the --recording-time option to stop recording after a certain number of seconds.
 *Quitting with CTRL-C/SIGINT writes remaining buffer to disk before ending program.

0.3.6 -> 0.3.7:
 *Fixed potentional buffer underrun error.

0.3.5 -> 0.3.6:
 *Fixed potentional ringbuffer size allocation miscalculation.
 *Better way to set leading zeros in filename. Thanks to Melanie.
 *Better underrun handling. Thanks to Dmitry Baikov.

0.3.4 -> 0.3.5:
 *Added support for jack buffer size change.
 *Removed some unnecessary code and comments
 *Beautified code a bit.

0.3.3 -> 0.3.4:
 *Fixed a bug in the reconnection code.
 *Beautified code a lot.

0.3.2 -> 0.3.3:
 *Changed bufsize argument to accept seconds instead of frames. Default buffer size is 60 seconds.
 *Improved documentation and help option.
 *Beautified source a bit.
 *Fixed bug in ringbuffer size allocation.

0.3.1 -> 0.3.2:
 *Fixed so that more than one instance of jack_capture can run at once.

0.3.0 -> 0.3.1:
 *Added the --port argument, which can be specified many times and accepts both input and output port names
 (including regexp expressions). This makes jack_capture to completely replace jackrec.

0.2.6 -> 0.3.0:
 *Rewrote buffer handling. Silence is now inserted when underruns occure. Previously, the
  file became shorter than the recording in case of underrun. It can still happen though, but
  much more seldom, and a warning about that will be printed to the terminal.
 *Removed last rests of jackrec code. Well, almost, at least.
 *Niceified code a lot.

0.2.5 -> 0.2.6:
 *Reduced CPU usage a lot because of better disk handling. (25% -> 1%)
 *Make sure the rest of the recorded file is not garbage in case of an overrun.
 *More efficient way of handling overruns.

0.2.4 -> 0.2.5:
 *Fixed really stupid compilation error. Thanks to Dragan Noveski for spotting it.

0.2.3 -> 0.2.4:
 *Give message to stderr during recording (not only after) if any overruns occur.
 *Do not delete file after recording if any overruns have occured. (stupid jackreq code #$!@$)
 *Increased default buffer size from 0.5M to 2M.

0.2.2 -> 0.2.3:
 *Added -z argument that choose number of leading zeros.
 *Various changes.

0.2.1 -> 0.2.2:
 *Only connect/disconnect ports if it's necessary. This puts less stress on the jack system
  and possibly avoids never ending connect/reconnecting loops.
 *Replaced the timemachine-way of automatically setting filename by a much simpler one. Now the
  autogenerated filename is just jack_capture_<n>.wav: jack_capture_1.wav, jack_capture_2.wav, 
  jack_capture_3.wav and so on.
 *If jack is shut down during recording, stop the recording properly.
 *Various smaller changes.

0.2.0 -> 0.2.1:
 *Removed optional -f argument (that didn't work anyway) for setting the filename. Usage for program is now:
  "jack_capture [ -b bitdepth ] [-c channels] [ -B bufsize ] [filename]"
  Thanks to Cesare Marilungo for pointing out the bug.
 *Sound filename is also printed to the screen.

0.1.1 -> 0.2.0:
 *Automatically disconnect and connect ports while program is running. Previously, the
  connections where only set up when the program started.
 *Added make install.
 *Various smaller changes.