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Errors
======
.. currentmodule:: av.error
.. _error_behaviour:
General Behavior
-----------------
When PyAV encounters an FFmpeg error, it raises an appropriate exception.
FFmpeg has a couple dozen of its own error types which we represent via
:ref:`error_classes`.
FFmpeg will also return more typical errors such as ``ENOENT`` or ``EAGAIN``,
which we do our best to translate to extensions of the builtin exceptions
as defined by
`PEP 3151 <https://www.python.org/dev/peps/pep-3151/#new-exception-classes>`_.
.. _error_classes:
Error Exception Classes
-----------------------
PyAV raises the typical builtin exceptions within its own codebase, but things
get a little more complex when it comes to translating FFmpeg errors.
There are two competing ideas that have influenced the final design:
1. We want every exception that originates within FFmpeg to inherit from a common
:class:`.FFmpegError` exception;
2. We want to use the builtin exceptions whenever possible.
As such, PyAV effectively shadows as much of the builtin exception hierarchy as
it requires, extending from both the builtins and from :class:`FFmpegError`.
Therefore, an argument error within FFmpeg will raise a ``av.error.ValueError``, which
can be caught via either :class:`FFmpegError` or ``ValueError``. All of these
exceptions expose the typical ``errno`` and ``strerror`` attributes (even
``ValueError`` which doesn't typically), as well as some PyAV extensions such
as :attr:`FFmpegError.log`.
All of these exceptions are available on the top-level ``av`` package, e.g.::
try:
do_something()
except av.FilterNotFoundError:
handle_error()
.. autoclass:: av.FFmpegError
|
