pysndfile 1.4.4

Description:

pysndfile 1.4.4

pysndfile is a python package providing PySndfile, a
Cython wrapper class around
libsndfile. PySndfile
provides methods for reading and writing a large variety of soundfile
formats on a variety of plattforms. PySndfile provides a rather complete
access to the different sound file manipulation options that are
available in libsndfile.
Due to the use of libsndfile nearly all sound file formats, (besides mp3
and derived formats) can be read and written with PySndfile.
The interface has been designed such that a rather large subset of the
functionality of libsndfile can be used, notably the reading and writing
of strings into soundfile formats that support these, and a number of
sf_commands that allow to control the way libsndfile reads and writes
the samples. One of the most important ones is the use of the clipping
command.

Transparent soundfile io with libsndfile
PySndfile has been developed in the analysis synthesis team at
IRCAM mainly for research on
sound analysis and sound transformation. In this context it is essential
that the reading and writing of soundfile data is transparent.
The use of the clipping mode of libsndfile is important here because
reading and writing sound data should not change the audio samples. By
default, when clipping is off, libsndfile uses slightly different
scaling factors when reading pcm format into float samples, or when
writing float samples into pcm format. Therefore whenever a complete
read/write cycle is applied to a sound file then the audio samples may
be modified even when no processing is applied.
More precisely this will happen if

the sound files contains pcm format,
and the data is read into float or double,
and the audio data comes close to the maximum range such that the
difference in scaling leads to modification.

To avoid this problem PySndfile sets clipping by default to on. If you
don’t like this you can set it to off individually using the PySndfile
method set_auto_clipping(False).


Implementation
The implementation is based on a slightly modified version of the header
sndfile.hh that is distributed with libsndfile. The only modification is
the addition of a methode querying the seekable state of the open
Sndfile.


Installation

via Anaconda channel roebel
Precompiled packages are available for Anaconda
python3 under Linux (x86_64)
and Mac OS X (> 10.9). For these systems you can install pysndfile
simply by means of
conda install -c roebel pysndfile
Unfortunately, I don’t have a windows machine and therefore I cannot
provide any packages for Windows.


compile with conda build recipe
You can use the conda recipe
here. This build recipe
wil automatically download and compile libsndfile building pysndfile.


via pypi
pip install pysndfile
should install pysndfile and python dependencies. Note, that pip cannot
install libsndfile for you as it is not provided via pypi. To install
libsndfile you should be able to use the software manager of your
system. This will however only work if your software manager installs
libsndfile such that the compiler used by the setup.py script will find
it.


compile from sources
Note that for ompiling from sources you need to install requirements
listed in requirements.txt file before starting the compilation.
Moreover you need to install libsndfile as described in the previous
section.
If the libsndfile (header and library) is not installed in the default
compiler search path you have to specify the library and include
directories to be added to this search paths. For this you can use
either the command line options –sndfile-libdir and –sndfile-incdir that
are available for the build_ext command or specify these two parameters
in the setup.cfg file.

Windows
An experimental support for using pysndfile under windows has been added
since version 1.3.4. For further comments see
here as well as
build
scripts
provided by sveinse. Note, that I do not have any windows machine and
cannot provide any help in making this work.




Documentation
Please see the developer documentation
here.


Changes

Version_1.4.4 (2022-03-11)

Fix for win32: improved error handling for PyUnicode_AsWideCharString
(thanks to Andrey Bienkowski)



Version_1.4.3 (2020-01-20)

changed sndio functions to all use PySndfile as context manager. This
fixes the problem that the sndfile remains open when an error occurs
which may in turn lead to inconsistencies if the sndfile is tried to
be rewritten in an exception handler.



Version_1.4.2 (2019-12-18)

fixed PySndfile.read_frames method to properly handle reading frames
in parts (previous fix was incomplete)



Version_1.4.1 (2019-12-18)

extended supported commands to change compression level when writing
flac and ogg files
fixed PySndfile.read_frames and sndio.read method to properly handle
reading frames from the middle of a file



Version_1.4.0 (2019-12-17)

Extended PySndfile class:

support use as context manager
added support for wve, ogg, MPC2000 sampler and RF64 wav files
added support for forcing to return 2D arrays even for mono files
added method to close the file and release all resources.
support reading more frames than present in the file using the
fill_value for all values positioned after the end of the file





Version_1.3.8 (2019-10-22)

(no changes in functionality)
added documentation to distributed files
added missing licence file to distribution
thanks @toddrme2178 for patches.



Version_1.3.7 (2019-08-01)

removed cython (a build requirement) from requirements.txt
avoid cython warning and fix language_level in the .pyx source code
add and support pre-release tags in the version number
use hashlib to calculate the README checksum.
fixed support for use with python 2.7 that was broken since 1.3.4



Version_1.3.6 (2019-07-27)

fixed potential but undesired build dependency of pandoc
added link to explanation for using pysndfile under windows
fixed pandoc problem that does produce non ASCII chars in rst output.



Version_1.3.5 (2019-07-27)

fixed two copy paste bug introduced in 1.3.4 1.3.4 did in fact not
work at all :-(
added a check target to the makefile that performs a complete
built/install/test cycle to avoid problems as in 1.3.4



Version_1.3.4 (2019-07-23)

added support for automatic installation of requirements
remove precompiled cython source file and rely on pip requirements to
provide cython so that cython compilation will always be possible.
added experimental support for installation on win32 (thanks to Svein
Seldal for the contributions).
use expanduser for replacing ~ in filenames
adapted cython source code to avoid all compiler warnings due to
deprecated numpy api
removed use of ez_setup.py that is no longer required.



Version_1.3.3 (2019-06-01)

fixed missing command C_SFC_SET_SCALE_INT_FLOAT_WRITE (thanks to
Svein Seldal for the bug report and fix)
better documentation of sf_string-io in sndio.read and sndio.write
limit size of strings to be written such that the written file can
always be read back with libsndfile 1.0.28 (which imposes different
constraints for different formats)
better error handling when number of channels exceeds channel limit
imposed by libsndfile.
sndio module now exposes the dicts: fileformat_name_to_id and
fileformat_id_to_name
extended sndio.read with force_2d argument that can be used to force
the returned data array to always have 2 dimensions even for mono
files.



Version_1.3.2 (2018-07-04)

fixed documentation of sndio module.



Version_1.3.1 (2018-07-04)

Extended sndio by means of adding a enw function that allows
retrieving embed markers from sound files. Names marker labels will
be retrieved only for aiff files.
removed print out in pysndfile.get_cue_mrks(self) function.
fixed version number in documentation.



Version_1.3.0 (2018-07-04)

Added support for retrieving cue points from aiff and wav files.



Version_1.2.2 (2018-06-11)

fixed c++-include file that was inadvertently scrambled.



Version_1.2.1 (2018-06-11)

fixed formatting error in long description and README.
setup.py to explicitly select formatting of the long description.



Version_1.2.0 (2018-06-11)

support reading and writing sound file strings in sndio module
Improved documentation of module constant mappings and PySndfile
methods.
Added a new method supporting to write all strings in a dictionary to
the sound file.



Version_1.1.1 (2018-06-10)
this update is purely administrative, no code changes

moved project to IRCAM GitLab
moved doc to ReadTheDoc
fixed documentation.



Version_1.1.0 (2018-02-13)

support returning extended sndfile info covering number of frames and
number of channels from function sndio.get_info.



Version_1.0.0 (2017-07-26)

Updated version number to 1.0.0:
pysndfile has now been used for quiet a while under python 3 and most
problems seem to be fixed.
changed setup.py to avoid uploading outdated LONG_DESC file.



Version_0.2.15 (2017-07-26)

fixed get_sndfile_version function and tests script: adapted char
handling to be compatible with python 3.



Version 0.2.14 (2017-07-26)

fixed filename display in warning messages due to invalid pointer:
replaced char* by std::string



Version 0.2.13 (2017-06-03)

fixed using “~” for representing $HOME in filenames:
_pysndfile.pyx: replaced using cython getenv by os.environ to avoid
type incompatibilities in python3



Version 0.2.12 (2017-05-11)

fixed problem in sndio.read: Optionally return full information
required to store the file using the corresponding write function
_pysndfile.pyx: add constants SF_FORMAT_TYPEMASK and
SF_FORMAT_SUBMASK, SF_FORMAT_ENDMASK to python interface Added new
function for getting internal sf log in case of errors. Improved
consistency of variable definitions by means of retrieving them
automatically from sndfile.h



Version 0.2.11 (2015-05-17)

setup.py: fixed problem with compilers not providing the compiler
attribute (MSVC) (Thanks to Felix Hanke for reporting the problem)
_pysndfile.pyx: fixed problem when deriving from PySndfile using a
modified list of init parameters in the derived class (Thanks to
Sam Perry for the suggestion).



Version 0.2.10

setup.py: rebuild LONG_DESC only if sdist method is used.



Version 0.2.9

Added missing files to distribution.
force current cythonized version to be distributed.



Version 0.2.4

Compatibility with python 3 (thanks to Eduardo Moguillansky)
bug fix: ensure that vectors returned by read_frames function own
their data.




Copyright
Copyright (C) 2014-2018 IRCAM


Author
Axel Roebel


Credits

Erik de Castro Lopo: for
libsndfile
David Cournapeau: for a few ideas I gathered from
scikits.audiolab.
The Cython maintainers for the efficient
means to write interface definitions in Cython.