1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
|
% Documentations stolen and LaTeX'ed from comments in file.
\section{\module{wave} ---
Read and write WAV files}
\declaremodule{standard}{wave}
\sectionauthor{Moshe Zadka}{mzadka@geocities.com}
\modulesynopsis{Provide an interface to the WAV sound format.}
The \module{wave} module provides a convenient interface to the WAV sound
format. It does not support compression/decompression, but it does support
mono/stereo.
The \module{wave} module defines the following function and exception:
\begin{funcdesc}{open}{file\optional{, mode}}
If \var{file} is a string, open the file by that name, other treat it
as a seekable file-like object. \var{mode} can be any of
\begin{description}
\item[\code{'r'}, \code{'rb'}] Read only mode.
\item[\code{'w'}, \code{'wb'}] Write only mode.
\end{description}
Note that it does not allow read/write WAV files.
A \var{mode} of \code{'r'} or \code{'rb'} returns a \class{Wave_read}
object, while a \var{mode} of \code{'w'} or \code{'wb'} returns
a \class{Wave_write} object. If \var{mode} is omitted and a file-like
object is passed as \var{file}, \code{\var{file}.mode} is used as the
default value for \var{mode} (the \character{b} flag is still added if
necessary).
\end{funcdesc}
\begin{funcdesc}{openfp}{file, mode}
A synonym for \function{open()}, maintained for backwards compatibility.
\end{funcdesc}
\begin{excdesc}{Error}
An error raised when something is impossible because it violates the
WAV specification or hits an implementation deficiency.
\end{excdesc}
\subsection{Wave_read Objects \label{Wave-read-objects}}
Wave_read objects, as returned by \function{open()}, have the
following methods:
\begin{methoddesc}[Wave_read]{close}{}
Close the stream, and make the instance unusable. This is
called automatically on object collection.
\end{methoddesc}
\begin{methoddesc}[Wave_read]{getnchannels}{}
Returns number of audio channels (\code{1} for mono, \code{2} for
stereo).
\end{methoddesc}
\begin{methoddesc}[Wave_read]{getsampwidth}{}
Returns sample width in bytes.
\end{methoddesc}
\begin{methoddesc}[Wave_read]{getframerate}{}
Returns sampling frequency.
\end{methoddesc}
\begin{methoddesc}[Wave_read]{getnframes}{}
Returns number of audio frames.
\end{methoddesc}
\begin{methoddesc}[Wave_read]{getcomptype}{}
Returns compression type (\code{'NONE'} is the only supported type).
\end{methoddesc}
\begin{methoddesc}[Wave_read]{getcompname}{}
Human-readable version of \method{getcomptype()}.
Usually \code{'not compressed'} parallels \code{'NONE'}.
\end{methoddesc}
\begin{methoddesc}[Wave_read]{getparams}{}
Returns a tuple
\code{(\var{nchannels}, \var{sampwidth}, \var{framerate},
\var{nframes}, \var{comptype}, \var{compname})}, equivalent to output
of the \method{get*()} methods.
\end{methoddesc}
\begin{methoddesc}[Wave_read]{readframes}{n}
Reads and returns at most \var{n} frames of audio, as a string of bytes.
\end{methoddesc}
\begin{methoddesc}[Wave_read]{rewind}{}
Rewind the file pointer to the beginning of the audio stream.
\end{methoddesc}
The following two methods are defined for compatibility with the
\refmodule{aifc} module, and don't do anything interesting.
\begin{methoddesc}[Wave_read]{getmarkers}{}
Returns \code{None}.
\end{methoddesc}
\begin{methoddesc}[Wave_read]{getmark}{id}
Raise an error.
\end{methoddesc}
The following two methods define a term ``position'' which is compatible
between them, and is otherwise implementation dependant.
\begin{methoddesc}[Wave_read]{setpos}{pos}
Set the file pointer to the specified position.
\end{methoddesc}
\begin{methoddesc}[Wave_read]{tell}{}
Return current file pointer position.
\end{methoddesc}
\subsection{Wave_write Objects \label{Wave-write-objects}}
Wave_write objects, as returned by \function{open()}, have the
following methods:
\begin{methoddesc}[Wave_write]{close}{}
Make sure \var{nframes} is correct, and close the file.
This method is called upon deletion.
\end{methoddesc}
\begin{methoddesc}[Wave_write]{setnchannels}{n}
Set the number of channels.
\end{methoddesc}
\begin{methoddesc}[Wave_write]{setsampwidth}{n}
Set the sample width to \var{n} bytes.
\end{methoddesc}
\begin{methoddesc}[Wave_write]{setframerate}{n}
Set the frame rate to \var{n}.
\end{methoddesc}
\begin{methoddesc}[Wave_write]{setnframes}{n}
Set the number of frames to \var{n}. This will be changed later if
more frames are written.
\end{methoddesc}
\begin{methoddesc}[Wave_write]{setcomptype}{type, name}
Set the compression type and description.
\end{methoddesc}
\begin{methoddesc}[Wave_write]{setparams}{tuple}
The \var{tuple} should be \code{(\var{nchannels}, \var{sampwidth},
\var{framerate}, \var{nframes}, \var{comptype}, \var{compname})}, with
values valid for the \method{set*()} methods. Sets all parameters.
\end{methoddesc}
\begin{methoddesc}[Wave_write]{tell}{}
Return current position in the file, with the same disclaimer for
the \method{Wave_read.tell()} and \method{Wave_read.setpos()}
methods.
\end{methoddesc}
\begin{methoddesc}[Wave_write]{writeframesraw}{data}
Write audio frames, without correcting \var{nframes}.
\end{methoddesc}
\begin{methoddesc}[Wave_write]{writeframes}{data}
Write audio frames and make sure \var{nframes} is correct.
\end{methoddesc}
Note that it is invalid to set any parameters after calling
\method{writeframes()} or \method{writeframesraw()}, and any attempt
to do so will raise \exception{wave.Error}.
|
