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Diffstat (limited to 'Lib/sunau.py')
| -rw-r--r-- | Lib/sunau.py | 207 |
1 files changed, 104 insertions, 103 deletions
diff --git a/Lib/sunau.py b/Lib/sunau.py index 0ba7dc9..5e8ac32 100644 --- a/Lib/sunau.py +++ b/Lib/sunau.py @@ -1,106 +1,107 @@ -# Stuff to parse Sun and NeXT audio files. -# -# An audio consists of a header followed by the data. The structure -# of the header is as follows. -# -# +---------------+ -# | magic word | -# +---------------+ -# | header size | -# +---------------+ -# | data size | -# +---------------+ -# | encoding | -# +---------------+ -# | sample rate | -# +---------------+ -# | # of channels | -# +---------------+ -# | info | -# | | -# +---------------+ -# -# The magic word consists of the 4 characters '.snd'. 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 header size really gives the start of the data. -# The data size is the physical size of the data. From the other -# parameter the number of frames can be calculated. -# The encoding gives the way in which audio samples are encoded. -# Possible values are listed below. -# The info field currently consists of an ASCII string giving a -# human-readable description of the audio file. The info field is -# padded with NUL bytes to the header size. -# -# Usage. -# -# Reading audio files: -# f = sunau.open(file, 'r') -# where file is either the name of a file or an open file pointer. -# The open file pointer must have methods read(), seek(), and close(). -# When the setpos() and rewind() methods are not used, the seek() -# method is not necessary. -# -# This returns an instance of a class with the following public methods: -# getnchannels() -- returns number of audio channels (1 for -# mono, 2 for stereo) -# getsampwidth() -- returns sample width in bytes -# getframerate() -- returns sampling frequency -# getnframes() -- returns number of audio frames -# getcomptype() -- returns compression type ('NONE' or 'ULAW') -# getcompname() -- returns human-readable version of -# compression type ('not compressed' matches 'NONE') -# getparams() -- returns a tuple consisting of all of the -# above in the above order -# getmarkers() -- returns None (for compatibility with the -# aifc module) -# getmark(id) -- raises an error since the mark does not -# exist (for compatibility with the aifc module) -# readframes(n) -- returns at most n frames of audio -# rewind() -- rewind to the beginning of the audio stream -# setpos(pos) -- seek to the specified position -# tell() -- return the current position -# close() -- close the instance (make it unusable) -# The position returned by tell() and the position given to setpos() -# are compatible and have nothing to do with the actual postion in the -# file. -# The close() method is called automatically when the class instance -# is destroyed. -# -# Writing audio files: -# f = sunau.open(file, 'w') -# where file is either the name of a file or an open file pointer. -# The open file pointer must have methods write(), tell(), seek(), and -# close(). -# -# This returns an instance of a class with the following public methods: -# setnchannels(n) -- set the number of channels -# setsampwidth(n) -- set the sample width -# setframerate(n) -- set the frame rate -# setnframes(n) -- set the number of frames -# setcomptype(type, name) -# -- set the compression type and the -# human-readable compression type -# setparams(tuple)-- set all parameters at once -# tell() -- return current position in output file -# writeframesraw(data) -# -- write audio frames without pathing up the -# file header -# writeframes(data) -# -- write audio frames and patch up the file header -# close() -- patch up the file header and close the -# output file -# You should set the parameters before the first writeframesraw or -# writeframes. The total number of frames does not need to be set, -# but when it is set to the correct value, the header does not have to -# be patched up. -# It is best to first set all parameters, perhaps possibly the -# compression type, and then write audio frames using writeframesraw. -# When all frames have been written, either call writeframes('') or -# close() to patch up the sizes in the header. -# The close() method is called automatically when the class instance -# is destroyed. +"""Stuff to parse Sun and NeXT audio files. + +An audio consists of a header followed by the data. The structure +of the header is as follows. + + +---------------+ + | magic word | + +---------------+ + | header size | + +---------------+ + | data size | + +---------------+ + | encoding | + +---------------+ + | sample rate | + +---------------+ + | # of channels | + +---------------+ + | info | + | | + +---------------+ + +The magic word consists of the 4 characters '.snd'. 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 header size really gives the start of the data. +The data size is the physical size of the data. From the other +parameter the number of frames can be calculated. +The encoding gives the way in which audio samples are encoded. +Possible values are listed below. +The info field currently consists of an ASCII string giving a +human-readable description of the audio file. The info field is +padded with NUL bytes to the header size. + +Usage. + +Reading audio files: + f = sunau.open(file, 'r') +where file is either the name of a file or an open file pointer. +The open file pointer must have methods read(), seek(), and close(). +When the setpos() and rewind() methods are not used, the seek() +method is not necessary. + +This returns an instance of a class with the following public methods: + getnchannels() -- returns number of audio channels (1 for + mono, 2 for stereo) + getsampwidth() -- returns sample width in bytes + getframerate() -- returns sampling frequency + getnframes() -- returns number of audio frames + getcomptype() -- returns compression type ('NONE' or 'ULAW') + getcompname() -- returns human-readable version of + compression type ('not compressed' matches 'NONE') + getparams() -- returns a tuple consisting of all of the + above in the above order + getmarkers() -- returns None (for compatibility with the + aifc module) + getmark(id) -- raises an error since the mark does not + exist (for compatibility with the aifc module) + readframes(n) -- returns at most n frames of audio + rewind() -- rewind to the beginning of the audio stream + setpos(pos) -- seek to the specified position + tell() -- return the current position + close() -- close the instance (make it unusable) +The position returned by tell() and the position given to setpos() +are compatible and have nothing to do with the actual postion in the +file. +The close() method is called automatically when the class instance +is destroyed. + +Writing audio files: + f = sunau.open(file, 'w') +where file is either the name of a file or an open file pointer. +The open file pointer must have methods write(), tell(), seek(), and +close(). + +This returns an instance of a class with the following public methods: + setnchannels(n) -- set the number of channels + setsampwidth(n) -- set the sample width + setframerate(n) -- set the frame rate + setnframes(n) -- set the number of frames + setcomptype(type, name) + -- set the compression type and the + human-readable compression type + setparams(tuple)-- set all parameters at once + tell() -- return current position in output file + writeframesraw(data) + -- write audio frames without pathing up the + file header + writeframes(data) + -- write audio frames and patch up the file header + close() -- patch up the file header and close the + output file +You should set the parameters before the first writeframesraw or +writeframes. The total number of frames does not need to be set, +but when it is set to the correct value, the header does not have to +be patched up. +It is best to first set all parameters, perhaps possibly the +compression type, and then write audio frames using writeframesraw. +When all frames have been written, either call writeframes('') or +close() to patch up the sizes in the header. +The close() method is called automatically when the class instance +is destroyed. +""" # from <multimedia/audio_filehdr.h> AUDIO_FILE_MAGIC = 0x2e736e64 |