22

✏️ Editing: wave.rst.txt

:mod:`wave` --- Read and write WAV files
========================================

.. module:: wave
   :synopsis: Provide an interface to the WAV sound format.
.. sectionauthor:: Moshe Zadka <moshez@zadka.site.co.il>
.. Documentations stolen from comments in file.

**Source code:** :source:`Lib/wave.py`

--------------

The :mod:`wave` module provides a convenient interface to the WAV sound format.
It does not support compression/decompression, but it does support mono/stereo.

The :mod:`wave` module defines the following function and exception:

.. function:: 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 a :class:`Wave_read` object, while a
   *mode* of ``'w'`` or ``'wb'`` returns a :class:`Wave_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
   :meth:`close` method is called; it is the caller's responsibility to close
   the file object.

.. function:: openfp(file, mode)

A synonym for :func:`.open`, maintained for backwards compatibility.

.. exception:: Error

An error raised when something is impossible because it violates the WAV
   specification or hits an implementation deficiency.

.. _wave-read-objects:

Wave_read Objects
-----------------

Wave_read objects, as returned by :func:`.open`, have the following methods:

.. method:: Wave_read.close()

Close the stream if it was opened by :mod:`wave`, and make the instance
   unusable.  This is called automatically on object collection.

.. method:: Wave_read.getnchannels()

Returns number of audio channels (``1`` for mono, ``2`` for stereo).

.. method:: Wave_read.getsampwidth()

Returns sample width in bytes.

.. method:: Wave_read.getframerate()

Returns sampling frequency.

.. method:: Wave_read.getnframes()

Returns number of audio frames.

.. method:: Wave_read.getcomptype()

Returns compression type (``'NONE'`` is the only supported type).

.. method:: Wave_read.getcompname()

Human-readable version of :meth:`getcomptype`. Usually ``'not compressed'``
   parallels ``'NONE'``.

.. method:: Wave_read.getparams()

Returns a tuple ``(nchannels, sampwidth, framerate, nframes, comptype,
   compname)``, equivalent to output of the :meth:`get\*` methods.

.. method:: Wave_read.readframes(n)

Reads and returns at most *n* frames of audio, as a string of bytes.

.. method:: Wave_read.rewind()

Rewind the file pointer to the beginning of the audio stream.

The following two methods are defined for compatibility with the :mod:`aifc`
module, and don't do anything interesting.

.. method:: Wave_read.getmarkers()

Returns ``None``.

.. method:: 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.

.. method:: Wave_read.setpos(pos)

Set the file pointer to the specified position.

.. method:: Wave_read.tell()

Return current file pointer position.

.. _wave-write-objects:

Wave_write Objects
------------------

Wave_write objects, as returned by :func:`.open`, have the following methods:

.. method:: Wave_write.close()

Make sure *nframes* is correct, and close the file if it was opened by
   :mod:`wave`.  This method is called upon object collection.

.. method:: Wave_write.setnchannels(n)

Set the number of channels.

.. method:: Wave_write.setsampwidth(n)

Set the sample width to *n* bytes.

.. method:: Wave_write.setframerate(n)

Set the frame rate to *n*.

.. method:: Wave_write.setnframes(n)

Set the number of frames to *n*. This will be changed later if more frames are
   written.

.. method:: Wave_write.setcomptype(type, name)

Set the compression type and description. At the moment, only compression type
   ``NONE`` is supported, meaning no compression.

.. method:: Wave_write.setparams(tuple)

The *tuple* should be ``(nchannels, sampwidth, framerate, nframes, comptype,
   compname)``, with values valid for the :meth:`set\*` methods.  Sets all
   parameters.

.. method:: Wave_write.tell()

Return current position in the file, with the same disclaimer for the
   :meth:`Wave_read.tell` and :meth:`Wave_read.setpos` methods.

.. method:: Wave_write.writeframesraw(data)

Write audio frames, without correcting *nframes*.

.. method:: Wave_write.writeframes(data)

Write audio frames and make sure *nframes* is correct.

Note that it is invalid to set any parameters after calling :meth:`writeframes`
or :meth:`writeframesraw`, and any attempt to do so will raise
:exc:`wave.Error`.

MR SKB