directvnc - a vnc client for the linux framebuffer device

directvnc server:display [options]

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. To find out more about VNC check out its home on the web at AT&T labs.

www.uk.research.att.com/vnc/

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. Find out all about DirectFB here:

www.directfb.org

DirectVNC basically provides a very thin VNC client for unix framebuffer systems.

Hitting <ctrl-q> exits the viewer.

-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 authentification. Use this with care!

-b, --bpp

the bits per pixel to be used by the client. Currently only 16 bpp are 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 useable 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 useable 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 compression 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.

Currently only 16 bpp color depth is supported.

Please tell me about them.

Copyright Till Adam 2001

Email bugs and feature requests to:

<directvnc-user@mail.freesoftware.fsf.org>