Vizserver man page

INDEX

SYNOPSIS

DESCRIPTION

COMPRESSION MODULES

USING A STEREO APPLICATION

ENVIRONMENT VARIABLES

SEE ALSO

SYNOPSIS

vizserver

 [-h server_host] [-a auth_field,...]
 [-S [session_name] | -J session_name]
 [-D] [-p config] [-A active_screens]
 [-c compressor] [-z] [-s [mode]]
 [-x]

DESCRIPTION

The vizserver command can be also used with the following options:

-h server_host

Makes the client connect to this server_host when starting OpenGL Vizserver.

-a auth_fields

Uses the values of auth_fields for the login process. auth_fields is a comma-separated list of authentication values, for example -a username,password.

-S [session_name]

Starts a session automatically. If session_name is not given a single user session will start. Otherwise a collaborative session named session_name is started.

-J session_name

Makes a user join in the collaborative session named session_name. This option can not be used with -S option at the same time.

-D

Enables desktop sharing, which is off by default. This option is ignored when used with the -J option.

-p config

Specifies the configuration when starting a session. The default is one pipe. For config, a number denotes the number of pipes and an alphanumeric string denotes a video group. This option is ignored when used with the -J option.

-A active_screens

Turns on OpenGL Vizserver serving for the screens specified by the values of active_screens The value active_screens is a comma-delimited list of screen numbers - for example, -A 0,2. If you do not specify the -A option, the default behavior is to serve all screens.

-z

Enables ZLIB compression, which is off by default. This option is ignored when used with the -J option.

-c compressor

Uses the specified compressor when starting a session. The compressor is one of vsIFCCC, vsIFICC, vsIFSCCC, vsIFSICC, and vsIFLLC. See the COMPRESSION MODULE section for more details. This argument is ignored when using with the -J option.

-s [mode]

Sets the spoiling mode when starting a session. The -s and -s 0 options turn spoiling off. The -s 1 option turns spoiling on (this is the default value). The -s 2 option turns on the Time-Based readback mode.

-x

Makes the client exit on failure or when stopping a session.

At startup, the main window is presented requesting the hostname for the server system. Once entered and Login selected, the GUI may optionally present a login dialog requesting any needed information for login (for some authentication strategies, this dialog is not needed).

When using the command-line option -h, OpenGL Vizserver client directly connects to server_host and gets to the login stage.

Once the login dialog is completed, the login request is submitted to the server. The information collected from the login dialog is authenticated by the server. If an error occurs, the GUI will simply indicate that the login attempt failed. The site administrator can help diagnose the specific failure.

When using the -a option, the login dialog will not be presented and the vizserver command will directly get to the session start stage.

Following successful login, it is possible to start a session, either a single-user or collaborative session, join a collaborative session, or logout from the main window.

Pressing the Start Session button brings up a session start dialog, requesting specific configuration information for the session before it is started. In this dialog the user set the initial configuration of the session including:
      o Is the session a desktop-sharing one
o The session's configuration (number of pipes or videoGroup)
o Which of the screens should be served to the client
o Which network interface to use
o Compression scheme
o Whether ZLIB compression is enabled or not
o Spoiling mode (on/off/time-based)
o Session type (single-user/collaborative)

By default, the session type is set to Collaboration and the session name is given as the form user@host but this name can be changed by the user. A session name must be entered for a collaborative session.

Client starting a session is the master of the session and there is only one master per session. Collaborative session has two types: local and remote. Local collaborative session involves a local master client running on the same host as the server and multiple clients to join later. Remote collaborative session involves a remote master client and multiple clients joining later. The supported number of clients in a collaborative session is 2 for a workstation license and the available count of license for a collaboration license. The served applications are viewed by all the clients, but in any given time only one client can interact with the applications and also alter the session's configuration by changing the compression scheme or spoiling mode.

If Single-User session type is chosen, the session name field in the dialog becomes disabled since the name is not necessary. Only one client can view and interact with the applications served in the session and the allocated graphic pipes of the session are used exclusively by that client. The client is also the master of the session.

Once a session has been started, a session control dialog is presented. This dialog presents the type and name of the active session, and allows for changes to the compression scheme and spoiling option, refreshing any active OpenGL Vizserver windows, and stopping the session. The control dialog for a collaborative session has two additional elements: a list of clients participating in the session and a selection box for the input control moderation between multiple clients.

The session startup sequence is completed when the OpenGL Vizserver console window appears on the client. The environment has been correctly setup for this window such that any application executed from this console will be visually served to the client(s).

It is also possible to serve (by the session) an application from another window. Simply login to the server system (e.g., using telnet or rlogin), using the user name for which the session has started, and prefix the application command line with the vsx(1) command.

In desktop sharing mode, the whole desktop on the server side is viewable on the client side rather than specific application windows. The OpenGL Vizserver console window is presented as part of the viewable desktop. As opposed to non-desktop sharing mode, every window viewable on the server-side desktop is also viewable on the client side, thus using the vsx(1) command is useless.

Choosing the Join Session button brings up a session join dialog, requesting necessary configuration information for joining the session, as well as the name of the collaborative session to be joined. In order to successfully join a collaborative session, the session must have been already started and the joining client needs to get the approval of the client mastering the session. When a new client joins the session, all other clients in the session are informed by getting an updated client list on their session control window.

When the -S option is used, the session configuration dialog will not be presented and configuration is done using the command line arguments -D, -p, -A, -c, -z and -s, as well as any other default configuration values.

From the session control window, the active compression scheme can be modified while the session is active. Changes to the compression scheme affect all active applications and result in refreshing of all windows belonging to OpenGL based applications. ZLIB compression can be turned on and off, and effects the compression of both the OpenGL regions and the non-OpenGL (pure X) regions of the application. Frame spoiling can be changed interactively. With frame spoiling turned on (default), the application is allowed to run freely and OpenGL Vizserver will only send the most up to date frames to the client(s), as a result some frames might never reach the client(s). When frame spoiling is turned off, the application is blocked until the client(s) receives the frame. With time-based mode enabled, frames are generated by the OprnGL Vizserver server regardless of the application's behavior.

For a single-user session and a remote collaborative session, depending on the server configuration, one or more graphic pipes might need to be reserved in advance for the use of the master of the session. A session will fail to start if not enough graphic pipes were reserved. If the user has a reservation and the session has started, it will be terminated at the end of the reserved period (a warning will be displayed in advance). OpenGL Vizserver server provides a simple web-based reservation client. If this module is already installed on the server side, it is accessible via URL: http://remote-host/vizserver/reservation, where remote-host should be replaced with the server's host name. This web site allows one to view, add and delete reservations. For details of the reservation system, refer to OpenGL Vizserver User's Guide.

The active session can be terminated using the Stop Session button from the session control window, choosing Logout from the main window or exiting the user interface application. Only the master of the session can stop the session. When a master client stops its session, the session ends and all the clients in the session including the master will have the session control window and OpenGL Vizserver console window closed.

COMPRESSION MODULES

The libvsIFCCC.so compression module supports five compression modes:
     

vsIFCCC

Color Cell Delta (8:1)

vsIFICC

Interpolated Color Cell Delta (4:1)

vsIFSCCC

Scaled Color Cell Delta (32:1)

vsIFSICC

Scaled Interpolated Color Cell Delta (16:1)

vsIFLLC

Lossless Delta (1:1)

The first four schemes are derived from the Block Truncation Coding (BTC) algorithm which compresses a 4x4 pixel block down to two colors plus a 4x4 pixel mask (see "Two Bit/Pixel Full Color Encoding", SIGGRAPH 86 Conference Proceedings, 1986 and "Hardware for Superior Texture Performance", EuroGraphics 95 Conference Proceedings, 1995 for more information on the basics of the schemes). The scaled versions scale the image by 50% before performing CCC or ICC compression algorithms. All these compression schemes transmit only the difference between consecutive frames, rather than the whole frame.

The variation between the CCC and ICC compressors lies in the number of colors identified by the pixel mask. In the case of CCC, the mask identifies two colors. The ICC mask identifies four colors. In both cases, the color components are converted to 5 bits of red, 6 bits of green and 5 bits of blue for 16 bits per pixel. The compression ratio for these two schemes is at least 8:1 for CCC and at least 4:1 for ICC. Scaled CCC and Scaled ICC algorithms have compression ratios of at least 32:1 and at least 16:1 respectively. Since all of these schemes are inter-frame, the compression ratio is higher for less changing frames.

The libvsJpegCompressor.so compression module provides the JPEG compression (ISO/IEC IS 10918-1 standard). There are four compression levels, which vary in quality and compression ratio:

JPEGCompressor90

90% quality (best), highest bit-rate

JPEGCompressor

70% quality

JPEGCompressor50

50% quality

JPEGCompressor20

20% quality (worst), lowest bit-rate

USING A STEREO APPLICATION

If VS_NO_STEREO environment variable is set, then all stereo functionality is disabled. This includes the disabling of receiving extra stereo buffers and video mode changes.

If VS_STEREO_NO_SWITCH environment variable is set, OpenGL Vizserver will NOT switch the client video mode. Instead, the user must change video mode manually.

If VS_STEREO_AUTO_SWITCH environment variable is set, OpenGL Vizserver will switch the client video mode directly for you, without prompting for confirmation using question dialogs. Using this environment variable is recommended only if you know that there are no problems with your monitor and the video formats used.

On Onyx4 platforms, the stereo video mode cannot be changed during X server run-time. Therefore, when using an Onyx4 client the two environment variables VS_STEREO_NO_SWITCH and VS_STEREO_AUTO_SWITCH have no effect.

ENVIRONMENT VARIABLES

SEE ALSO

vsx(1)
OpenGL Vizserver User's Guide

INDEX

NAME

SYNOPSIS

DESCRIPTION

COMPRESSION MODULES

USING A STEREO APPLICATION

ENVIRONMENT VARIABLES

SEE ALSO