Informations

Description

$ jack_capture

• 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)

• Originally based on the jackrec program in the jack distribution made by Paul Davies and Jack O'Quin. Not much left of that code now. http://www.jackaudio.org
• Peak indicator code for the console meter taken from meterbridge by Steve Harris. http://plugin.org.uk/meterbridge/
• Unmodified atomic lifo/fifo code taken from midishare. (Copyright Grame 1999-2005) http://midishare.sf.net
• atomic_add function copied from the jack source. (www.jackaudio.org)
• Code for writing to stdout was made by looking at http://mir.dnsalias.com/oss/jackstdout/start made by Robin Gareus.