File Formats; Using Standard Output - Townshend Computer Tools DAT-Link User Manual

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6.9 File Formats

In the above sections we have assumed the le being stored contains just audio
data stored as 16 bit signed integers. This default is called the
formats are available by using the
of possible formats can be display at any time by typing:
narecord -f help
Appendix B.1 describes the encoding of each format. In addition to the overall le
format, the type of data encoding can be speci ed using the
encoding choices are:
:
Direct linear encoding of the data as signed integers. The precision of the
Linear
values defaults to 16 bits/sample, but can be changed using the
described below. This is the default encoding.
:
IEEE oating point format using 4 bytes/sample.
IEEE
:
One byte per sample, A-law companded data.
ALaw
:
One byte per sample,
uLaw
For example, the command:
narecord -f raw -e ieee -t 10 file
records 10 seconds of data and stores it as oating point numbers.
For the linear encoding, the number of bits/sample can also be speci ed using the
option. To record a le using 20-bit samples:
-p
narecord -p20 file
Note that the data is assumed to be packed such that every pair of samples will
occupy 5 bytes. Valid choices of the precision are 4, 8, 12, 16, 20, 24, 28, or 32
bits/sample.
Note that not all combinations of the
formats support only particular encodings and precisions. Also, when sample-rate
conversion is used only 16 bits/sample, linear encoding is available.

6.10 Using Standard Output

If no lename is given on the command line, then the audio data will be directed to
the standard output. This allows another program which accepts sampled data to
option followed by a format name. A full list
-f
-law companded data.

, , and options are valid. Certain le
-f -e -p
Recording Tutorial
format. Other
raw
option. The valid
-e
option
-p