21.5. wave — Read and write WAV files — Python documentation
21.5. wave — Read and write WAV files
Source code: :source:`Lib/wave.py`
The wave module provides a convenient interface to the WAV sound format. It does not support compression/decompression, but it does support mono/stereo.
The wave module defines the following function and exception:
- wave.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'
,'rb'
Read only mode.
'w'
,'wb'
Write only mode.
Note that it does not allow read/write WAV files.
A mode of
'r'
or'rb'
returns aWave_read
object, while a mode of'w'
or'wb'
returns aWave_write
object. If mode is omitted and a file-like object is passed as file,file.mode
is used as the default value for mode (the'b'
flag is still added if necessary).If you pass in a file-like object, the wave object will not close it when its
close()
method is called; it is the caller’s responsibility to close the file object.
- wave.openfp(file, mode)
- A synonym for open(), maintained for backwards compatibility.
- exception wave.Error
- An error raised when something is impossible because it violates the WAV specification or hits an implementation deficiency.
21.5.1. Wave_read Objects
Wave_read objects, as returned by open(), have the following methods:
- Wave_read.close()
- Close the stream if it was opened by wave, and make the instance unusable. This is called automatically on object collection.
- Wave_read.getnchannels()
- Returns number of audio channels (
1
for mono,2
for stereo).
- Wave_read.getsampwidth()
- Returns sample width in bytes.
- Wave_read.getframerate()
- Returns sampling frequency.
- Wave_read.getnframes()
- Returns number of audio frames.
- Wave_read.getcomptype()
- Returns compression type (
'NONE'
is the only supported type).
- Wave_read.getcompname()
- Human-readable version of getcomptype(). Usually
'not compressed'
parallels'NONE'
.
- Wave_read.getparams()
- Returns a tuple
(nchannels, sampwidth, framerate, nframes, comptype, compname)
, equivalent to output of theget*()
methods.
- Wave_read.readframes(n)
- Reads and returns at most n frames of audio, as a string of bytes.
- Wave_read.rewind()
- Rewind the file pointer to the beginning of the audio stream.
The following two methods are defined for compatibility with the aifc module, and don’t do anything interesting.
- Wave_read.getmarkers()
- Returns
None
.
- Wave_read.getmark(id)
- Raise an error.
The following two methods define a term “position” which is compatible between them, and is otherwise implementation dependent.
- Wave_read.setpos(pos)
- Set the file pointer to the specified position.
- Wave_read.tell()
- Return current file pointer position.
21.5.2. Wave_write Objects
Wave_write objects, as returned by open(), have the following methods:
- Wave_write.close()
- Make sure nframes is correct, and close the file if it was opened by wave. This method is called upon object collection.
- Wave_write.setnchannels(n)
- Set the number of channels.
- Wave_write.setsampwidth(n)
- Set the sample width to n bytes.
- Wave_write.setframerate(n)
- Set the frame rate to n.
- Wave_write.setnframes(n)
- Set the number of frames to n. This will be changed later if more frames are written.
- Wave_write.setcomptype(type, name)
- Set the compression type and description. At the moment, only compression type
NONE
is supported, meaning no compression.
- Wave_write.setparams(tuple)
- The tuple should be
(nchannels, sampwidth, framerate, nframes, comptype, compname)
, with values valid for theset*()
methods. Sets all parameters.
- Wave_write.tell()
- Return current position in the file, with the same disclaimer for the Wave_read.tell() and Wave_read.setpos() methods.
- Wave_write.writeframesraw(data)
- Write audio frames, without correcting nframes.
- Wave_write.writeframes(data)
- Write audio frames and make sure nframes is correct.
Note that it is invalid to set any parameters after calling writeframes()
or writeframesraw()
, and any attempt to do so will raise wave.Error.