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NA_RECORD(1) General Commands Manual NA_RECORD(1)

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:

Prints a short summary of usage to standard output.
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.
device
Sets the audio device to record from, if supported by the audio protocol chosen (e.g. /dev/dsp, /dev/audio)
seconds
Stops recording after the specified number of seconds.
file
Writes sound output to the specified file
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.
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.
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.
Swap bytes when saving to output.
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).
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.

ENVIRONMENT

Audio protocol to use (as in the -p flag)
Host to record audio from when using a network audio protocol.

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)

SEE ALSO

na_play(1)

April 4, 2001 Edinburgh Speech Tools