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Video Console Support in Asterisk

Some console drivers (at the moment can be built with support for sending and receiving video. In order to have this working you need to perform the following steps:

Enable building the video_console support

The simplest way to do it is add this one line to channels/Makefile:

Install prerequisite packages

The video_console support relies on the presence of SDL, SDL_image and ffmpeg libraries, and of course on the availability of X11

On Linux, these are supplied by

  • libncurses-dev
  • libsdl1.2-dev
  • libsdl-image1.2-dev
  • libavcodec-dev
  • libswcale-dev

On FreeBSD, you need the following ports:

  • multimedia/ffmpeg (2007.10.04)
  • devel/sdl12 graphics/sdl_image
Build and install asterisk with all the above

Make sure you do a 'make clean' and run configure again after you have installed the required packages, to make sure that the required pieces are found.

Check that is generated and correctly installed.

Update configuration files

Video support requires explicit configuration as described below:

You need to set various parameters for video console, the easiest way is to uncomment the following line in oss.conf by removing the leading ';'

You also need to manually copy the two files

  • images/kpad2.jpg
  • images/font.png

into the places specified in oss.conf, which in the sample are set to

other configuration parameters are described in oss.conf.sample


To actually run a call using SIP (the same probably applies to iax.conf) you need to enable video support as following

You can add other video formats e.g. h261, h264, mpeg if they are supported by your version of libavcodec.

Run the Program

Run asterisk in console mode e.g. asterisk -vdc

If video console support has been successfully compiled in, then you will see the "console startgui" command available on the CLI interface. Run the command, and you should see a window like this

To exit from this window, in the console run "console stopgui".

If you want to start a video call, you need to configure your dialplan so that you can reach (or be reachable) by a peer who can support video. Once done, a video call is the same as an ordinary call:

"console dial ...", "console answer", "console hangup" all work the same.

To use the GUI, and also configure video sources, see the next section.

Video Sources

Video sources are declared with the "videodevice=..." lines in oss.conf where the ... is the name of a device (e.g. /dev/video0 ...) or a string starting with X11 which identifies one instance of an X11 grabber.

You can have up to 9 sources, displayed in thumbnails in the gui, and select which one to transmit, possibly using Picture-in-Picture.

For webcams, the only control you have is the image size and frame rate (which at the moment is the same for all video sources). X11 grabbers capture a region of the X11 screen (it can contain anything, even a live video) and use it as the source. The position of the grab region can be configured using the GUI below independently for each video source.

The actual video sent to the remote side is the device selected as "primary" (with the mouse, see below), possibly with a small 'Picture-in-Picture' of the "secondary" device (all selectable with the mouse).

GUI Commands and Video Sources

(most of the text below is taken from channels/console_gui.c)

The GUI is made of 4 areas: remote video on the left, local video on the right, keypad with all controls and text windows in the center, and source device thumbnails on the top. The top row is not displayed if no devices are specified in the config file.

    |  ______   ______   ______   ______   ______   ______   ______  |
    | | tn.1 | | tn.2 | | tn.3 | | tn.4 | | tn.5 | | tn.6 | | tn.7 | |
    | |______| |______| |______| |______| |______| |______| |______| |
    |  ______   ______   ______   ______   ______   ______   ______  |
    | |______| |______| |______| |______| |______| |______| |______| |
    |  _________________    __________________    _________________  |
    | |                 |  |                  |  |                 | |
    | |                 |  |                  |  |                 | |
    | |                 |  |                  |  |                 | |
    | |   remote video  |  |                  |  |   local video   | |
    | |                 |  |                  |  |          ______ | |
    | |                 |  |      keypad      |  |         |  PIP || |
    | |                 |  |                  |  |         |______|| |
    | |_________________|  |                  |  |_________________| |
    |                      |                  |                      |
    |                      |                  |                      |
    |                      |__________________|                      |

The central section is built using an image (jpg, png, maybe gif too) for the skin and other GUI elements. Comments embedded in the image indicate to what function each area is mapped to.

Another image (png with transparency) is used for the font.

Mouse and keyboard events are detected on the whole surface, and handled differently according to their location:

  • Center/right click on the local/remote window are used to resize the corresponding window
  • Clicks on the thumbnail start/stop sources and select them as primary or secondary video sources
  • Drag on the local video window are used to move the captured area (in the case of X11 grabber) or the picture-in-picture position
  • Keystrokes on the keypad are mapped to the corresponding key; keystrokes are used as keypad functions, or as text input
    if we are in text-input mode.
  • Drag on some keypad areas (sliders etc.) are mapped to the corresponding functions (mute/unmute audio and video,
    enable/disable Picture-in-Picture, freeze the incoming video, dial numbers, pick up or hang up a call, ...)
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1 Comment

  1. Where can one find a list of channels that support video calls?

    I've looked for "video" in chan_oss.c and found relevant references; the idea was to look for the same strings in other files - thus identify the ones that can handle video.