NAME
qarecord − an audio recording tool
SYNOPSIS
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.
AUTHORS
Matthias Nagorni, Frank Kober, Guido Scholz and David Henningsson. This manual page was written by David Henningsson <qarecord [AT] epost.se>.