__init__.py

# flake8: noqa
"""
Stempeg is a python package to read and write [STEM](https://www.native-instruments.com/en/specials/stems/) files.
Technically, stems are audio containers that combine multiple audio streams and metadata in a single audio file. This makes it ideal to playback multitrack audio, where users can select the audio sub-stream during playback (e.g. supported by VLC). 

Under the hood, _stempeg_ uses [ffmpeg](https://www.ffmpeg.org/) for reading and writing multistream audio, optionally [MP4Box](https://github.com/gpac/gpac) is used to create STEM files that are compatible with Native Instruments hardware and software.

- `stempeg.read`: reading audio tensors and metadata.
- `stempeg.write`: writing audio tensors.

![stempeg_scheme](https://user-images.githubusercontent.com/72940/102477776-16960a00-405d-11eb-9389-1ea9263cf99d.png)

Please checkout [the Github repository](https://github.com/faroit/stempeg) for more information.
"""

from .read import read_stems
from .read import Info
from .read import StreamsReader, ChannelsReader
from .write import write_stems
from .write import write_audio
from .write import FilesWriter, StreamsWriter, ChannelsWriter, NIStemsWriter

from .cmds import check_available_aac_encoders

import re
import subprocess as sp
import importlib.resources as importlib_resources
import atexit
from contextlib import ExitStack

__version__ = "0.2.2"


def example_stem_path():
    """Get the path to an included stem file.

    Returns
    -------
    filename : str
        Path to the stem file
    """
    file_manager = ExitStack()
    atexit.register(file_manager.close)
    ref = importlib_resources.files(__name__) / 'data/The Easton Ellises - Falcon 69.stem.mp4'
    path = file_manager.enter_context(importlib_resources.as_file(ref))
    return str(path)


def default_metadata():
    """Get the path to included stems metadata.

    Returns
    -------
    filename : str
        Path to the json file
    """
    file_manager = ExitStack()
    atexit.register(file_manager.close)
    ref = importlib_resources.files(__name__) / 'data/default_metadata.json'
    path = file_manager.enter_context(importlib_resources.as_file(ref))
    return str(path)


def ffmpeg_version():
    """Returns the available ffmpeg version

    Returns
    ----------
    version : str
        version number as string
    """

    cmd = [
        'ffmpeg',
        '-version'
    ]

    output = sp.check_output(cmd)
    aac_codecs = [
        x for x in
        output.splitlines() if "ffmpeg version " in str(x)
    ][0]
    hay = aac_codecs.decode('ascii')
    match = re.findall(r'ffmpeg version \w?(\d+\.)?(\d+\.)?(\*|\d+)', hay)
    if match:
        return "".join(match[0])
    else:
        return None