jpsamaroo / videoio.jl

Julia bindings for libav/ffmpeg

VideoIO.jl

Julia bindings for libav/ffmpeg.

Currently, only video reading is supported, for the following library versions:

• libav 0.8, 9, 10
• ffmpeg 2.2 through 3.0

Video images may be read as raw arrays, or optionally, Image objects (if Images.jl is installed and loaded first).

Feel free to request support for additional libav/ffmpeg versions, although earlier versions may be too challenging to support.

If you encounter any problems, please add the output of VideoIO.versioninfo() to your report.

Installation

Use the Julia package manager. Within Julia, do:

Pkg.add("VideoIO")

Simple Interface

A trivial video player interface exists (no audio):

import ImageView
import VideoIO

f = VideoIO.testvideo("annie_oakley")  # downloaded if not available
VideoIO.playvideo(f)  # no sound

# Aternatively, you can just open the camera
#VideoIO.viewcam()

Note that ImageView must be imported before VideoIO for the playvideo function to be available.

High Level Interface

VideoIO contains a simple high-level interface which allows reading of video frames from a supported video file, or from a camera device:

using Images
import ImageView
import VideoIO

io = VideoIO.open(video_file)
f = VideoIO.openvideo(io)

# As a shortcut for just video, you can upen the file directly
# with openvideo
#f = VideoIO.openvideo(video_file)

# Alternatively, you can open the camera with opencamera().
# The default device is "0" on Windows, "/dev/video0" on Linux,
# and "Integrated Camera" on OSX.  If using something other
# than the default, pass it in as the first parameter (as a string).
#f = VideoIO.opencamera()

# One can seek to an arbitrary position in the video
seek(f,2.5)  ## The second parameter is the time in seconds and must be Float64
img = read(f)
canvas = ImageView.imshow(img)["gui"]["canvas"]

while !eof(f)
    read!(f, img)
    ImageView.imshow(canvas, img)
    #sleep(1/30)
end

This code is essentially the code in playvideo, and will read and (without the sleep) play a movie file as fast as possible.

As with the playvideo function, the Images and ImageView packages must be loaded before VideoIO for the appropriate functions to be available.

Low Level Interface

Each libav and ffmpeg library has its own VideoIO subpackage:

libavcodec    -> AVCodecs
libavdevice   -> AVDevice
libavfilter   -> AVFilters
libavformat   -> AVFormat
libavutil     -> AVUtil
libswscale    -> SWScale

The following three files are related to ffmpeg/libav, but currently not exposed:

libavresample -> AVResample (libav only)
libswresample -> SWResample (ffmpeg only)
libpostproc   -> PostProc   (not wrapped)

After importing VideoIO, you can import and use any of the subpackages directly

import VideoIO
import SWResample  # SWResample functions are now available

Note that much of the functionality of these subpackages is not enabled by default, to avoid long compilation times as they load. To control what is loaded, each library version has a file which imports that's modules files. For example, ffmpeg's libswscale-v2 files are loaded by $(VideoIO_PKG_DIR)/src/ffmpeg/SWScale/v2/LIBSWSCALE.jl.

Check these files to enable any needed functionality that isn't already enabled. Note that you'll probably need to do this for each version of the package for both ffmpeg and libav, and that the interfaces do change some from version to version.

Note that, in general, the low-level functions are not very fun to use, so it is good to focus initially on enabling a nice, higher-level function for these interfaces.

Test Videos

A small number of test videos are available through VideoIO.TestVideos. These are short videos in a variety of formats with non-restrictive (public domain or Creative Commons) licenses.

• VideoIO.TestVideos.available() prints a list of all available test videos.
• VideoIO.testvideo("annie_oakley") returns an AVInput object for the "annie_oakley" video. The video will be downloaded if it isn't available.
• VideoIO.TestVideos.download_all() downloads all test videos
• VideoIO.TestVideos.remove_all() removes all test videos

Status

At this point, a simple video interface is available, for multiple versions of libav and ffmpeg. See TODO.md for some possible directions forward.

Issues, requests, and/or pull requests for problems or additional functionality are very welcome.