__init__.py 2.96 KB
Newer Older
1
import os
2
import warnings
3

4
import torch
5
from torchvision import datasets
6
7
from torchvision import io
from torchvision import models
8
from torchvision import ops
9
10
from torchvision import transforms
from torchvision import utils
11

12
from .extension import _HAS_OPS
13

14
15
try:
    from .version import __version__  # noqa: F401
Soumith Chintala's avatar
Soumith Chintala committed
16
except ImportError:
17
    pass
18

19
# Check if torchvision is being imported within the root folder
20
21
22
23
24
25
26
27
if not _HAS_OPS and os.path.dirname(os.path.realpath(__file__)) == os.path.join(
    os.path.realpath(os.getcwd()), "torchvision"
):
    message = (
        "You are importing torchvision within its own root folder ({}). "
        "This is not expected to work and may give errors. Please exit the "
        "torchvision project source and relaunch your python interpreter."
    )
28
29
    warnings.warn(message.format(os.getcwd()))

30
_image_backend = "PIL"
31

32
33
_video_backend = "pyav"

34
35
36
37
38
39

def set_image_backend(backend):
    """
    Specifies the package used to load images.

    Args:
40
41
42
        backend (string): Name of the image backend. one of {'PIL', 'accimage'}.
            The :mod:`accimage` package uses the Intel IPP library. It is
            generally faster than PIL, but does not support as many operations.
43
44
    """
    global _image_backend
45
    if backend not in ["PIL", "accimage"]:
46
        raise ValueError(f"Invalid backend '{backend}'. Options are 'PIL' and 'accimage'")
47
48
49
50
51
52
53
54
    _image_backend = backend


def get_image_backend():
    """
    Gets the name of the package used to load images
    """
    return _image_backend
55
56


57
58
59
60
61
62
63
def set_video_backend(backend):
    """
    Specifies the package used to decode videos.

    Args:
        backend (string): Name of the video backend. one of {'pyav', 'video_reader'}.
            The :mod:`pyav` package uses the 3rd party PyAv library. It is a Pythonic
64
65
66
            binding for the FFmpeg libraries.
            The :mod:`video_reader` package includes a native C++ implementation on
            top of FFMPEG libraries, and a python API of TorchScript custom operator.
67
            It generally decodes faster than :mod:`pyav`, but is perhaps less robust.
68
69

    .. note::
70
        Building with FFMPEG is disabled by default in the latest `main`. If you want to use the 'video_reader'
71
        backend, please compile torchvision from source.
72
73
74
    """
    global _video_backend
    if backend not in ["pyav", "video_reader"]:
75
        raise ValueError("Invalid video backend '%s'. Options are 'pyav' and 'video_reader'" % backend)
76
    if backend == "video_reader" and not io._HAS_VIDEO_OPT:
77
        message = "video_reader video backend is not available. Please compile torchvision from source and try again"
78
        warnings.warn(message)
79
80
    else:
        _video_backend = backend
81
82
83


def get_video_backend():
84
85
86
87
88
89
90
    """
    Returns the currently active video backend used to decode videos.

    Returns:
        str: Name of the video backend. one of {'pyav', 'video_reader'}.
    """

91
92
93
    return _video_backend


94
95
def _is_tracing():
    return torch._C._get_tracing_state()