na_record — play
waveform files on audio device
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 ... |
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:
-h- Prints a short summary of usage to standard output.
-itype
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.
-n
channels- Number of channels, in an unheadered input file. Again, this can usually
be determined from the headers. Default is 1.
-f
sampling rate- Sampling rate, for an unheadered input file. Default is 16000.
-ibo
byte order- Byte order, for an unheadered input file. Default is system byte order.
Recognized values are: MSB, LSB, native, nonnative.
-iswap- Swap bytes in an unheadered input file.
-istype
type- Sample type for an unheadered input file. Recognized values are: short,
mulaw, byte, ascii.
-c
channel- Select a single channel (starting at 0) for playback. This option plays
only the specified channel and discards all others.
-start
time- Select a subsection of the file, starting at this time (specified in
seconds).
-end
time- Select a subsection of the file, ending at this time (specified in
seconds).
-from
sample- Select a subsection of the file, starting at this offset (specified in
number of samples).
-to
sample- Select a subsection of the file, ending at this offset (specified in
number of samples).
-p
protocol- Use the specified audio device protocol. The list of supported types
varies between platforms, and can be obtained using the
-h flag.
-command
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.
-basic- Treat unheadered input files as 8kHz mu-law data (i.e. audio/basic MIME
type)
-quality
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.
-server
host- Specifies the host to play sound on, when using a network-aware audio
protocol (such as NAS)
-scale
scale- Change the gain (volume) of the signal. The argument is a number relative
to 1.0, which is the default.
-v- Be verbose (i.e. print file names when playing)
-wait- Pause for a keystroke between each file.
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
The usage information isn't entirely correct. The audio_command
protocol generates temporary files insecurely.