qarecord (1)
Leading comments
Manual page for qarecord Process with: groff -man -Tascii qarecord.1 | less Get a printable version with: groff -mandoc -Tps qarecord.1 > qarecord.ps
NAME
qarecord - an audio recording toolSYNOPSIS
qarecord [ alsa-options ] [ general-options ]
qarecord --jack [ general-options ]
qarecord { --help | --version }
DESCRIPTION
qarecord is a simple but solid recording tool. qarecord works well with both stereo and multichannel recordings, with both ALSA and JACK, and in both 16 bit and 32 bit mode. By using a large ringbuffer for the captured data, buffer overruns are avoided. qarecord has a Qt based GUI with graphical peak meters.MIDI trigger
In addition to the buttons in the GUI, recording can be started and stopped via MIDI. qarecord uses the ALSA sequencer for this purpose.File naming
A save file dialog appears the first time recording is activated, or through selecting New... in the File menu. If that file already exists, the old file will be renamed (to filename.oldx.wav), where x is an incrementing number. Should the file grow larger than the split limit, the file will be closed and recording will continue in a new file filename.partx.wav, where x is an incrementing number.Scheduling and priorities
qarecord has one high-priority thread that fetches data from ALSA and one normal priority thread that writes the data to disk. This will work best if the user is allowed to run realtime priority (rtprio) threads, see limits.conf(5) for more information. In JACK mode, the same reasoning applies, but it is handled by JACK, see jackd(1) for more information.
A ringbuffer is used to buffer the data before it is written to disk.
OPTIONS
General options
- --32bit
- If specified, a 32 bit WAVE will be the output format. If not specified, a 16 bit WAVE file will be recorded.
- --buffersize bytes
- The size of the ringbuffer in bytes. The default (1048576) should be sufficient for most purposes. It must be a multiple of the frame size (channels * bytes per channel).
- --channels num
- Number of channels to record. The default is 2, which means a stereo recording.
- --jack
- If specified, qarecord works as a JACK client. If not specified, qarecord uses ALSA for recording.
- --meterrange dB
- Specifies the dynamic range of the peak meters. The default value of 85 means that the meter will show signals between -85 dB and 0 dB.
- --midiChannel channel
- Specifies what MIDI channel the MIDI trigger should listen to. The default is 16, the valid range is 1..16.
- --midiNote num
- Specifies what MIDI notes the MIDI trigger should listen to. This note will be used to trigger recording, the next note will trigger pause, and note+2 will trigger stop. The default is 21, which translates to note A1 being used to record, A#1 for pause, and B1 for stop.
- --split MB
- Start a new wave file every MB megabytes. Default is 2000.
ALSA specific options
- --device ALSA device
- The ALSA device name to use for capture. The default is plughw:0, which means the first soundcard.
- --fragments num
- Number of fragments, or periods. Used with the periodsize option to determine the hardware buffer size. The default is 2.
- --periodsize frames
- Number of frames between ALSA signals that new data is available. The hardware buffer size will be periodsize * fragments. A large hardware buffer size might decrease the risc for a buffer underrun. The default is 2048.
- --rate Hz
- Sample rate. The default is 44100.
Standard options
- --help
- Print possible command-line options and exit.
- --version
-
Print version information and exit.
NOTES
Errors and warnings are written to stderr(3).
Due to limitations in the WAVE file format, larger files than 4 GB cannot
be recorded.