directvnc(1) General Commands Manual directvnc(1)
NAME
directvnc - a vnc client for the linux framebuffer device
SYNOPSIS
directvnc server:display [options]
DESCRIPTION
DirectVNC is a client implementing the remote framebuffer protocol (rfb) which is used by VNC servers. If a VNC server is running on a
machine you can connect to it using this client and have the contents of its display shown on your screen. Keyboard and mouse events are
sent to the server, so you can basically control a VNC server remotely. There are servers (and other clients) freely available for all
operating systems.
What makes DirectVNC different from other unix vnc clients is that it uses the linux framebuffer device through the DirectFB library which
enables it to run on anything that has a framebuffer without the need for a running X server. This includes embedded devices. DirectFB
even uses acceleration features of certain graphics cards. Thus a lot of configuration can be done by creating the library specific config-
uration file /etc/directfbrc or the program-specific configuration file /etc/directfbrc.directvnc. See directfbrc(5) or find out all about
DirectFB here:
www.directfb.org
DirectVNC basically provides a very thin VNC client for unix framebuffer systems.
QUITTING
Hitting <ctrl-q> exits the viewer.
OPTIONS
-h, --help
display help output and exit
-v, --version
output version information and exit
-p, --password
password string to be passed to the server for authentication. Use this with care!
-b, --bpp
the bits per pixel to be used by the client. Currently only 16 and 24 bpp are available.
-e --encodings
DirectVNC supports several different compression methods to encode screen updates; this option specifies a set of them to use in order
of preference. Encodings are specified separated with spaces, and must thus be enclosed in quotes if more than one is specified.
Available encodings, in default order for a remote connection, are "copyrect tight hextile zlib corre rre raw". For a local connection
(to the same machine), the default order to try is "raw copyrect tight hextile zlib corre rre". Raw encoding is always assumed as a
last option if no other encoding can be used for some reason.
-f --pollfrequency
time in ms to wait between polls for screen updates when no events are to be processed. This reduces cpu and network load. Default is
50 ms.
-s, --shared (default)
Don't disconnect already connected clients.
-n, --noshared
Disconnect already connected clients.
-n, --nolocalcursor
Disable local cursor tracking By default, and if the server is capable of the SoftCursor encoding, mouse movements do not generate
framebuffer updates and the cursor state is kept locally. This removes mouse pointer lag and lets the connection appear faster.
-c --compresslevel level
Use specified compression level (0..9) for "tight" and "zlib" encodings (only usable with servers capable of those encodings). Level
1 uses minimum of CPU time and achieves weak compression ratios, while level 9 offers best compression but is slow in terms of CPU
time consumption on the server side. Use high levels with very slow network connections, and low levels when working over high-speed
LANs. It's not recommended to use compression level 0, reasonable choices start from the level 1.
-q --quality level
Use the specified image quality level (0..9) for "tight" encoding (only usable with servers capable of those encodings). Specifying
this option allows "tight" encoder to use lossy JPEG compression. Quality level 0 denotes bad image quality but very impressive com-
pression ratios, while level 9 offers very good image quality at lower compression ratios. Note that "tight" encoder uses JPEG to
encode only those screen areas that look suitable for lossy compression, so quality level 0 does not always mean unacceptable image
quality.
-m --modmap PATH
Path to the modmap (subset of X-style) file to load. With this option, it is possible to set an alternative keyboard layout, with
ability to support non-latin characters such as Cyrillic. A plain text file, containing a subset of xmodmap(1) syntax (only keycode
expressions are recognized with up to four KEYSYMNAMEs) can be converted into the format that directvnc understands, and can be loaded
upon directvnc startup with this option. See directvnc-kbmapping(7).
LIMITATIONS
At the moment, it is still necessary to use the --bpp command line option to set color depth. When negotiating with the remote VNC server
side, color depth supplied by the server will be used. It is therefore necessary to make sure (at least in the present) that screen color
depth (default, or set in the DirectFB configuration file), color depth supplied at the command line, and remote VNC server color depth all
match.
SEE ALSO
directfbrc(5), directvnc-kbmapping(7), directvnc-xmapconv(1), xmodmap(1)
AUTHORS
Till Adam, Dimitry Golubovsky, Malte S. Stretz, Loris Boillet and others, based on AT&T and tightvnc VNC implementations.
Mar 5, 2010 directvnc(1)