User Documentation
RAVL, Recognition And Vision Library
Ravl - Contrib - Image IO - Video4Linux

Interface to Video 4 Linux frame grabbers

This adds two new virtual files '@V4L' and '@V4LH' which can be used to access video for linux drivers.

  • V4L - Gets full sized images from the image source.
  • V4LH - Gets half sized (in each dimension) images.
The filename is constructed as follows: @V4L:(device name)[#(channel no)]
  • (device name) - Name of video device, typically /dev/video0
  • (channel no) - Adding a # followed by a number to the filename sets the input channel number. If its omitted, it defaults to 0

NOTE: To use the Video4Linux driver you must include the library RavlImgIOV4L in your USESLIBS line of the

The following code will grab a single image (See Ravl.Core.IO):

      ImageC<ByteYUVValueC> x;
      Load("@V4L:/dev/video0#0", x);
or a seqence of images (See Ravl.OS.Sequence) :
    DPIPortC<ImageC<ByteYUVValueC> > in;
    if(!OpenISequence(in,"@V4L:/dev/video0#0")) {
      // Failed to open input file.
      // Report an error...
    ImageC<ByteYUVValueC> value;
    while(in.Get(value)) {
      // Process your data...


Normal classes:

 DPIImageV4LC V4L frame grabber.

Advanced classes:

 FileFormatV4LC Create an instance of a V4L File Format.
Documentation by CxxDoc: Tue Aug 13 10:00:52 2002