Configuring WSS (Widescreen Signaling)

Note: the description is valid for software versions 1.7.62 and higher

WSS (widescreen signaling) is the special signal included to the TV signal, serving to switch the TV receiver to the correct mode of displaying the Aspect Ratio. The WSS signal is placed in the twenty-third TV line (for the 576i format) and contains fourteen bit of information. Visually WSS looks like this (see the picture):




wss_2.jpgConfiguring the WSS generation is implemented from the server control panel - Administrator Control Panel. Login to the console is implemented locally from the server, or from any machine in the network by the address http://server_ip:7901. You should login as an administrator.


After the login to the control console, choose Manage at the left menu of the console. Choose the tab Video IO Boards, choose Edit in the window of the appropriate Playout service, then move to editing the parameters of the output signal. Activate the parameter Output WSS in the window Configure Service. To save the settings, press Apply Changes at the top part of the server control console. Now the output signal will constantly contain WSS data.


You can check WSS generation from the control web console, menu item Status. In the field Format of the appropriate window, displaying the status of the Playout service, you can set the format 4x3 or 16x9 and check the reaction of the TV-receiver/monitor.


You must send to the control TV-receiver the analogue low-frequency signal CVBS-PAL from the server output, or the signal received after the conversion of SD SDI from the server output to CVBS (PAL/SECAM). As far as TVs do not support WSS decoding within HDMI, you should not use SDI-HDMI conversions for checking (the line with WSS will be visible, but the switching will not be implemented).


The TV receiver should have the launched mode of WSS receiving (for Philips TVs, for example, the mode of displaying “Auto zoom” activates the function of switching the formats according to WSS data).

Automatic Generation of WSS-information

SL NEO platform allows automatic change of WSS data according to the information about the aspect ratio, contained in media-clips that are placed in the server database. You can see the information about the aspect ratio in the Media Browser window of the application Air Manager, by the right-click on the selected clip: tab Show Info, column Aspect. Information about the aspect ratio is sent to the server database while importing the appropriate media file, or is formed while recording, in accordance with the recorder settings.


For auto generation of WSS data you should create two rules (Action) according to which the data about the aspect ratio will be generated according to the information contained in the media-material.


The first rule is setting the output format 16x9 in case, if the initial material (clip) has the parameter 16x9 


The procedure can be also implemented from the control web console, menu item Status. In the window displaying the status of the Playout service you should find the field Format and set the type of format Default; in the window displaying the status of the service Program Channel also set the format Default in the field Format.


Choose the menu item Manage, find the tab Program Outputs. Find the tab Actions in the chosen program channel, click the item General Events, choose Add Action. In the opened window enter the parameters of a rule for the controlling the output format of the Playout service.


wss_3.jpgIn the window Edit Action, enter a random name for the rule to the field Name, choose “1” in the field Layer. Specify the server IP address in the field Address, or leave the field empty, if the value is localhost. In the field Service press the button  and choose from the list the name of the service for controlling. In our example, it is the output playout channel #1 (Playout_1 on the list). 


In the field Action press the button and choose a command Set Format that will be executed. In the field Condition choose a rule that will cause execution of the command - Media Aspect Ratio 16x9, in the field Param 1 specify the output format which will be set in case of triggering the rule - 16x9


The second rule - setting the output format 4x3 in case if the initial material has the parameter 4x3

Configuring the second rule is identical to the procedure described above.  To save the settings, click Apply Changes at the top part of the control console window. You can control the change of formats from the control console, menu item Status. The values 16x9 or 4x3 will being changed in the field Format of the appropriate window, displaying the status of the Playout service, the WSS data will being changed in the output signal. 


In case, when graphic design is formed by means of the server, you may need creating rules for the program channel (Program_Channel) to exclude geometric distortions of graphics and logo.