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FFMPEG wrapper for Python
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dspinellis and almarklein Avoid exception under Cygwin
Cygwin is a hybrid between Windows and Unix.  It does not currently
provide ffmpeg as a package, so the user will have to rely on Windows
builds, such as the [Zeranoe]( ones.
Setting winNN can work with such an installation and a suitable path.

Issue: #26
Latest commit 53b1533 Dec 10, 2019
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tests added bits_per_pixel parameter to read_frames Nov 25, 2019
LICENSE Initial commit Jan 28, 2019 PKG: Include readme and license in sdist Feb 10, 2019 update readme with new api Apr 12, 2019 Add requirement on pip 19+ in (#16) Apr 12, 2019


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FFMPEG wrapper for Python


The purpose of this project is to provide a simple and reliable ffmpeg wrapper for working with video files. It implements two simple generator functions for reading and writing data from/to ffmpeg, which reliably terminate the ffmpeg process when done. It also takes care of publishing platform-specific wheels that include the binary ffmpeg executables.

This library is used as the basis for the imageio ffmpeg plugin, but it can also be used by itself. Imageio provides a higher level API, and adds support for e.g. cameras and seeking.


This library works with any version of Python 3.4+ (including Pypy). There are no further dependencies. The wheels on Pypi include the ffmpeg executable for all common platforms (Windows 7+, Linux kernel 2.6.32+, OSX 10.9+). Install using:

$ pip install --upgrade imageio-ffmpeg

(On Linux you may want to first pip install -U pip, since pip 19 is needed to detect the manylinux2010 wheels.)

If you're using a Conda environment: the conda package does not include the ffmpeg executable, but instead depends on the ffmpeg package from conda-forge. Install using:

$ conda install imageio-ffmpeg -c conda-forge

If you don't want to install the included ffmpeg, you can use pip with --no-binary or conda with --no-deps. Then use the IMAGEIO_FFMPEG_EXE environment variable if needed.


The imageio_ffmpeg library provides low level functionality to read and write video data, using Python generators:

# Read a video file
reader = read_frames(path)
meta = reader.__next__()  # meta data, e.g. meta["size"] -> (width, height)
for frame in reader:
    ... # each frame is a bytes object

# Write a video file
writer = write_frames(path, size)  # size is (width, height)
writer.send(None)  # seed the generator
for frame in frames:
writer.close()  # don't forget this

How it works

This library calls ffmpeg in a subprocess, and video frames are communicated over pipes. This is certainly not the fastest way to use ffmpeg, but it makes it possible to wrap ffmpeg with pure Python, making distribution and installation much easier. And probably the code itself too. In contrast, PyAV wraps ffmpeg at the C level.


def read_frames(path, pix_fmt="rgb24", bpp=3, input_params=None, output_params=None):
    Create a generator to iterate over the frames in a video file.
    It first yields a small metadata dictionary that contains:
    * ffmpeg_version: the ffmpeg version is use (as a string).
    * codec: a hint about the codec used to encode the video, e.g. "h264"
    * source_size: the width and height of the encoded video frames
    * size: the width and height of the frames that will be produced
    * fps: the frames per second. Can be zero if it could not be detected.
    * duration: duration in seconds. Can be zero if it could not be detected.
    After that, it yields frames until the end of the video is reached. Each
    frame is a bytes object.
    This function makes no assumptions about the number of frames in
    the data. For one because this is hard to predict exactly, but also
    because it may depend on the provided output_params. If you want
    to know the number of frames in a video file, use count_frames_and_secs().
    It is also possible to estimate the number of frames from the fps and
    duration, but note that even if both numbers are present, the resulting
    value is not always correct.
        gen = read_frames(path)
        meta = gen.__next__()
        for frame in gen:
        path (str): the file to write to.
        pix_fmt (str): the pixel format of the frames to be read.
            The default is "rgb24" (frames are uint8 RGB images).
        bpp (int): The number of bytes per pixel in the output frames.
            This depends on the given pix_fmt. Default is 3 (RGB).
        input_params (list): Additional ffmpeg input command line parameters.
        output_params (list): Additional ffmpeg output command line parameters.
def write_frames(
    Create a generator to write frames (bytes objects) into a video file.
    The frames are written by using the generator's `send()` method. Frames
    can be anything that can be written to a file. Typically these are
    bytes objects, but c-contiguous Numpy arrays also work.
        gen = write_frames(path, size)
        gen.send(None)  # seed the generator
        for frame in frames:
        gen.close()  # don't forget this
        path (str): the file to write to.
        size (tuple): the width and height of the frames.
        pix_fmt_in (str): the pixel format of incoming frames.
            E.g. "gray", "gray8a", "rgb24", or "rgba". Default "rgb24".
        pix_fmt_out (str): the pixel format to store frames. Default yuv420p".
        fps (float): The frames per second. Default 16.
        quality (float): A measure for quality between 0 and 10. Default 5.
            Ignored if bitrate is given.
        bitrate (str): The bitrate, e.g. "192k". The defaults are pretty good.
        codec (str): The codec. Default "libx264" (or "msmpeg4" for .wmv).
        macro_block_size (int): You probably want to align the size of frames
            to this value to avoid image resizing. Default 16. Can be set
            to 1 to avoid block alignment, though this is not recommended.
        ffmpeg_log_level (str): The ffmpeg logging level. Default "warning".
        ffmpeg_timeout (float): Timeout in seconds to wait for ffmpeg process
            to finish. Value of 0 will wait forever. The time that ffmpeg needs
            depends on CPU speed, compression, and frame size. Default 20.0.
        input_params (list): Additional ffmpeg input command line parameters.
        output_params (list): Additional ffmpeg output command line parameters.
def count_frames_and_secs(path):
    Get the number of frames and number of seconds for the given video
    file. Note that this operation can be quite slow for large files.
    Disclaimer: I've seen this produce different results from actually reading
    the frames with older versions of ffmpeg (2.x). Therefore I cannot say
    with 100% certainty that the returned values are always exact.
def get_ffmpeg_exe():
    Get the ffmpeg executable file. This can be the binary defined by 
    the IMAGEIO_FFMPEG_EXE environment variable, the binary distributed
    with imageio-ffmpeg, an ffmpeg binary installed with conda, or the
    system ffmpeg (in that order). A RuntimeError is raised if no valid
    ffmpeg could be found.
def get_ffmpeg_version():
    Get the version of the used ffmpeg executable (as a string).
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