The sunau module provides a convenient interface to the Sun
AU sound format. Note that this module is interface-compatible with
the modules aifc and wave.
An audio file consists of a header followed by the data. The fields
of the header are:
Field
Contents
magic word
The four bytes ".snd".
header size
Size of the header, including info, in bytes.
data size
Physical size of the data, in bytes.
encoding
Indicates how the audio samples are encoded.
sample rate
The sampling rate.
# of channels
The number of channels in the samples.
info
ASCII string giving a description of the audio
file (padded with null bytes).
Apart from the info field, all header fields are 4 bytes in size.
They are all 32-bit unsigned integers encoded in big-endian byte
order.
The sunau module defines the following functions:
open(
file, mode)
If file is a string, open the file by that name, otherwise treat it
as a seekable file-like object. mode can be any of
'r'
Read only mode.
'w'
Write only mode.
Note that it does not allow read/write files.
A mode of 'r' returns a AU_read
object, while a mode of 'w' or 'wb' returns
a AU_write object.
openfp(
file, mode)
A synonym for open, maintained for backwards compatibility.
The sunau module defines the following exception:
exceptionError
An error raised when something is impossible because of Sun AU specs or
implementation deficiency.
The sunau module defines the following data items:
AUDIO_FILE_MAGIC
An integer every valid Sun AU file begins with, stored in big-endian
form. This is the string ".snd" interpreted as an integer.
AUDIO_FILE_ENCODING_MULAW_8
AUDIO_FILE_ENCODING_LINEAR_8
AUDIO_FILE_ENCODING_LINEAR_16
AUDIO_FILE_ENCODING_LINEAR_24
AUDIO_FILE_ENCODING_LINEAR_32
AUDIO_FILE_ENCODING_ALAW_8
Values of the encoding field from the AU header which are supported by
this module.
AUDIO_FILE_ENCODING_FLOAT
AUDIO_FILE_ENCODING_DOUBLE
AUDIO_FILE_ENCODING_ADPCM_G721
AUDIO_FILE_ENCODING_ADPCM_G722
AUDIO_FILE_ENCODING_ADPCM_G723_3
AUDIO_FILE_ENCODING_ADPCM_G723_5
Additional known values of the encoding field from the AU header, but
which are not supported by this module.
