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NA_PLAY(1) General Commands Manual NA_PLAY(1)

NAME

na_record — play waveform files on audio device

SYNOPSIS

na_play [-h] [-itype type] [-n channels] [-f sample rate] [-ibo byteorder] [-iswap] [-istype type] [-c channel] [-start time] [-end time] [-from sample] [-to sample] [-p protocol] [-command command] [-basic] [-quality high | low] [-server host] [-scale scale] [-v] [-wait] input files ...

DESCRIPTION

na_play plays digital audio data to the system's audio input device from the specified file(s). It supports a variety of file formats and native audio devices.

The following option flags are recognized:

Prints a short summary of usage to standard output.
type
Input file type. Usually, the input type can be determined from the file's headers, so this option is not required except for raw (unheadered) data. Supported types are currently: nist, est, esps, snd, riff, aiff, audlab, raw, ascii.
channels
Number of channels, in an unheadered input file. Again, this can usually be determined from the headers. Default is 1.
sampling rate
Sampling rate, for an unheadered input file. Default is 16000.
byte order
Byte order, for an unheadered input file. Default is system byte order. Recognized values are: MSB, LSB, native, nonnative.
Swap bytes in an unheadered input file.
type
Sample type for an unheadered input file. Recognized values are: short, mulaw, byte, ascii.
channel
Select a single channel (starting at 0) for playback. This option plays only the specified channel and discards all others.
time
Select a subsection of the file, starting at this time (specified in seconds).
time
Select a subsection of the file, ending at this time (specified in seconds).
sample
Select a subsection of the file, starting at this offset (specified in number of samples).
sample
Select a subsection of the file, ending at this offset (specified in number of samples).
protocol
Use the specified audio device protocol. The list of supported types varies between platforms, and can be obtained using the -h flag.
command
If the "audio_command" protocol is specified, this argument must be given to select the command used to play the waveform. A temporary file is created and passed in the environment variable FILE. The sample rate is passed in the environment varialbe SR.
Treat unheadered input files as 8kHz mu-law data (i.e. audio/basic MIME type)
high | low
Select the quality of output. "high" will ensure that proper resampling is used. "low" means to play as fast as possible with a minimum of processor time.
host
Specifies the host to play sound on, when using a network-aware audio protocol (such as NAS)
scale
Change the gain (volume) of the signal. The argument is a number relative to 1.0, which is the default.
Be verbose (i.e. print file names when playing)
Pause for a keystroke between each file.

ENVIRONMENT

Audio protocol to use (as in the -p flag)
Command used to play audio when using the audio_command protocol.
Host to play audio on when using a network audio protocol.
Playback quality (low or high)

EXAMPLES

To play the section of foo.wav from 1.5 to 3.2 seconds:

$ na_play -start 1.5 -end 3.2 foo.wav
To play samples 3600 to 42000 of channel 1 of bar.wav:
$ na_play -from 3600 -to 4200 -c 1 foo.wav

BUGS

The usage information isn't entirely correct. The audio_command protocol generates temporary files insecurely.

SEE ALSO

na_record(1)

April 4, 2001 Edinburgh Speech Tools