io.rst

Reading/Writing images and videos

.. currentmodule:: torchvision.io

The :mod:`torchvision.io` package provides functions for performing IO operations. They are currently specific to reading and writing video and images.

Video

.. autosummary::
    :toctree: generated/
    :template: function.rst

    read_video
    read_video_timestamps
    write_video

Fine-grained video API

In addition to the :mod:`read_video` function, we provide a high-performance lower-level API for more fine-grained control compared to the :mod:`read_video` function. It does all this whilst fully supporting torchscript.

.. betastatus:: fine-grained video API

.. autosummary::
    :toctree: generated/
    :template: class.rst

    VideoReader

Example of inspecting a video:

import torchvision
video_path = "path to a test video"
# Constructor allocates memory and a threaded decoder
# instance per video. At the moment it takes two arguments:
# path to the video file, and a wanted stream.
reader = torchvision.io.VideoReader(video_path, "video")

# The information about the video can be retrieved using the
# `get_metadata()` method. It returns a dictionary for every stream, with
# duration and other relevant metadata (often frame rate)
reader_md = reader.get_metadata()

# metadata is structured as a dict of dicts with following structure
# {"stream_type": {"attribute": [attribute per stream]}}
#
# following would print out the list of frame rates for every present video stream
print(reader_md["video"]["fps"])

# we explicitly select the stream we would like to operate on. In
# the constructor we select a default video stream, but
# in practice, we can set whichever stream we would like
video.set_current_stream("video:0")

Image

.. autosummary::
    :toctree: generated/
    :template: class.rst

    ImageReadMode

.. autosummary::
    :toctree: generated/
    :template: function.rst

    read_image
    decode_image
    encode_jpeg
    decode_jpeg
    write_jpeg
    encode_png
    decode_png
    write_png
    read_file
    write_file