bazarr/libs/pysubs2/formatbase.py
2018-10-31 17:08:29 +01:00

76 lines
2.7 KiB
Python

class FormatBase(object):
"""
Base class for subtitle format implementations.
How to implement a new subtitle format:
1. Create a subclass of FormatBase and override the methods you want to support.
2. Decide on a format identifier, like the ``"srt"`` or ``"microdvd"`` already used in the library.
3. Add your identifier and class to :data:`pysubs2.formats.FORMAT_IDENTIFIER_TO_FORMAT_CLASS`.
4. (optional) Add your file extension and class to :data:`pysubs2.formats.FILE_EXTENSION_TO_FORMAT_IDENTIFIER`.
After finishing these steps, you can call :meth:`SSAFile.load()` and :meth:`SSAFile.save()` with your
format, including autodetection from content and file extension (if you provided these).
"""
@classmethod
def from_file(cls, subs, fp, format_, **kwargs):
"""
Load subtitle file into an empty SSAFile.
If the parser autodetects framerate, set it as ``subs.fps``.
Arguments:
subs (SSAFile): An empty :class:`SSAFile`.
fp (file object): Text file object, the subtitle file.
format_ (str): Format identifier. Used when one format class
implements multiple formats (see :class:`SubstationFormat`).
kwargs: Extra options, eg. `fps`.
Returns:
None
Raises:
pysubs2.exceptions.UnknownFPSError: Framerate was not provided and cannot
be detected.
"""
raise NotImplementedError("Parsing is not supported for this format")
@classmethod
def to_file(cls, subs, fp, format_, **kwargs):
"""
Write SSAFile into a file.
If you need framerate and it is not passed in keyword arguments,
use ``subs.fps``.
Arguments:
subs (SSAFile): Subtitle file to write.
fp (file object): Text file object used as output.
format_ (str): Format identifier of desired output format.
Used when one format class implements multiple formats
(see :class:`SubstationFormat`).
kwargs: Extra options, eg. `fps`.
Returns:
None
Raises:
pysubs2.exceptions.UnknownFPSError: Framerate was not provided and
``subs.fps is None``.
"""
raise NotImplementedError("Writing is not supported for this format")
@classmethod
def guess_format(self, text):
"""
Return format identifier of recognized format, or None.
Arguments:
text (str): Content of subtitle file. When the file is long,
this may be only its first few thousand characters.
Returns:
format identifier (eg. ``"srt"``) or None (unknown format)
"""
return None