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whatsnew: Wave_write handles unseekable files. (#5202)

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Also clarify the documentation of this feature.
This commit is contained in:
R David Murray 2014-03-08 11:14:29 -05:00
parent 19f1df6414
commit 5d6240e871
2 changed files with 29 additions and 6 deletions
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31
Doc/library/wave.rst
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@ -150,14 +150,30 @@ them, and is otherwise implementation dependent.
Wave_write Objects Wave_write Objects
------------------ ------------------
For seekable output streams, the ``wave`` header will automatically be updated
to reflect the number of frames actually written. For unseekable streams, the
*nframes* value must be accurate when the first frame data is written. An
accurate *nframes* value can be achieved either by calling
:meth:`~Wave_write.setnframes` or :meth:`~Wave_write.setparams` with the number
of frames that will be written before :meth:`~Wave_write.close` is called and
then using :meth:`~Wave_write.writeframesraw` to write the frame data, or by
calling :meth:`~Wave_write.writeframes` with all of the frame data to be
written. In the latter case :meth:`~Wave_write.writeframes` will calculate
the number of frames in the data and set *nframes* accordingly before writing
the frame data.
Wave_write objects, as returned by :func:`.open`, have the following methods: Wave_write objects, as returned by :func:`.open`, have the following methods:
.. versionchanged:: 3.4
Added support for unseekable files.
.. method:: Wave_write.close() .. method:: Wave_write.close()
Make sure *nframes* is correct, and close the file if it was opened by Make sure *nframes* is correct, and close the file if it was opened by
:mod:`wave`. This method is called upon object collection. Can raise an :mod:`wave`. This method is called upon object collection. It will raise
exception if *nframes* is not correct and a file is not seekable. an exception if the output stream is not seekable and *nframes* does not
match the number of frames actually written.
.. method:: Wave_write.setnchannels(n) .. method:: Wave_write.setnchannels(n)
@ -181,8 +197,9 @@ Wave_write objects, as returned by :func:`.open`, have the following methods:
.. method:: Wave_write.setnframes(n) .. method:: Wave_write.setnframes(n)
Set the number of frames to *n*. This will be changed later if more frames are Set the number of frames to *n*. This will be changed later if the number
written. of frames actually written is different (this update attempt will
raise an error if the output stream is not seekable).
.. method:: Wave_write.setcomptype(type, name) .. method:: Wave_write.setcomptype(type, name)
@ -214,8 +231,10 @@ Wave_write objects, as returned by :func:`.open`, have the following methods:
.. method:: Wave_write.writeframes(data) .. method:: Wave_write.writeframes(data)
Write audio frames and make sure *nframes* is correct. Can raise an Write audio frames and make sure *nframes* is correct. It will raise an
exception if a file is not seekable. error if the output stream is not seekable and the total number of frames
that have been written after *data* has been written does not match the
previously set value for *nframes*.
.. versionchanged:: 3.4 .. versionchanged:: 3.4
Any :term:`bytes-like object`\ s are now accepted. Any :term:`bytes-like object`\ s are now accepted.

4
Doc/whatsnew/3.4.rst
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@ -1439,6 +1439,10 @@ plain tuple. (Contributed by Claudiu Popa in :issue:`17487`.)
:meth:`wave.open` now supports the context manager protocol. (Contributed :meth:`wave.open` now supports the context manager protocol. (Contributed
by Claudiu Popa in :issue:`17616`.) by Claudiu Popa in :issue:`17616`.)
:mod:`wave` can now :ref:`write output to unssekable files
<wave-write-objects>`. (Contributed by David Jones, Guilherme Polo, and Serhiy
Storchaka in :issue:`5202`.)
weakref weakref
------- -------