NAME¶
na_record
—
record waveform from audio device
SYNOPSIS¶
na_record |
[-h ] [-f
sampling rate] [-audiodevice
device] [-time
seconds] [-o
file] [-otype
type] [-ostype
sample type] [-F
sample rate] [-obo
MSB | LSB |
native] [-oswap ]
[-p audio device
protocol] |
DESCRIPTION¶
na_record
records digital audio data from the system's
audio input device and writes it to the specified file. It supports a variety
of output file formats and native audio devices.
The following option flags are recognized:
-h
- Prints a short summary of usage to standard output.
-f
sampling rate
- Sets the input sampling rate (in samples per second, i.e. Hz). Not all
devices support all sampling rates, so it may be desirable to set this
separately from the output sampling rate.
-audiodevice
device
- Sets the audio device to record from, if supported by the audio protocol
chosen (e.g. /dev/dsp, /dev/audio)
-time
seconds
- Stops recording after the specified number of seconds.
-o
file
- Writes sound output to the specified file
-otype
type
- Specifies the file format to use for output. Supported types currently
include nist, est, dsps, snd, riff, aiff, audlab, raw, and ascii. The
-h
flag will show the most accurate list. The
default type is nist.
-F
sampling rate
- Sets the output sampling rate (again, in samples per second, i.e. Hz). If
this differs from the input sampling rate, resampling will be done.
Defaults to 16000Hz.
-obo
byte order
- Sets the output byte order. Supported values are MSB, LSB, and native.
Many file formats have their own byte order, or are byte order
independent, so this isn't tremendously useful except for raw data. The
default is the native byte order for the system audio device.
-oswap
- Swap bytes when saving to output.
-ostype
sample type
- Sets the sample type of the output. Supported values are short, mulaw,
byte, or ascii. Again, this is usually implied by the file format, so
should only be used for raw data. The default is short (i.e. 16-bit
PCM).
-p
audio device protocol
- Selects an audio device protocol (i.e. type of audio device) to use. This
varies between different installations of Speech Tools, but defaults to
the most 'native' audio device, usually Open Sound System on Linux and
*BSD and /dev/audio on Solaris.
EXAMPLES¶
To record five seconds of audio from /dev/dsp1 (on Linux) to foo.wav in RIFF
format at 32kHz:
$ na_record -time 5 -audiodevice
/dev/dsp1 -o foo.wav -otype RIFF -f 32000
To record one second of audio to bar.wav in raw format in 8kHz mu-law:
$ na_record -time 1 -o bar.wav -otype
raw -ostype mulaw -f 8000
BUGS¶
The -time
argument only accepts integer values (though
the usage message implies otherwise)