Chapter 12. Broadcast Tools

The collaboration support in Ultimedia Services consists of a suite of broadcast tools that allow you to capture audio and/or video data, transmit it over a network that supports the Internet Protocol (IP), and then receive and play it on one or more systems simultaneously. Uses for this capability could include:

To learn more about the collaboration tools, see:

• Broadcast Tools Overview
• NetRepeater
• NetTunneler
• Sender
• Receiver .

Broadcast Tools Overview

There are four basic broadcast tools that makeup the Ultimedia Services collaboration suite. These tools are:

The Broadcast Tools figure illustrates the interoperation of these tools.

In the Multimedia folder of desktop's Application Manager, these four tools are represented by the following six icons:

NetRepeater

NetRepeater receives tunneled data from the network and rebroadcasts that data in multicast mode to the specified network.

Starting the NetRepeater

The NetRepeater can be started either by entering a command on the command line, or by selecting the NetRepeater icon located in the Multimedia folder of desktop's Application Manager and entering the connection parameters listed in the dialog box that displays.

Note: Starting the NetRepeater by selecting the icon method automatically brings up a terminal window. This window can be minimized into an icon until you want to exit the NetRepeater (see "Exiting the NetRepeater").

To start the NetRepeater, type:

NetRepeater [-a addr] [-d] [-n net] [-p port] -t tunnelPort

Where:

Exiting the NetRepeater

The NetRepeater can be exited by either entering the Ctrl-C keystroke sequence in the terminal window in which the NetRepeater command was entered or by closing the terminal window that was brought up when the NetRepeater icon was selected.

NetTunneler

NetTunneler receives multicast data from the network then tunnels the data to a repeater or a receiver on another network.

Starting the NetTunneler

The NetTunneler can be started either by entering a command on the command line, or by selecting the NetTunneler icon located in the Multimedia folder of desktop's Application Manager and entering the connection parameters listed in the displayed dialog box.

Note: Note: Starting the NetTunneler by selecting the icon automatically brings up a terminal window. This window can be minimized into an icon until you want to exit the NetTunneler (see "Exiting the NetTunneler").

To start the NetTunneler, type:

NetTunneler [-a addr] [-d] -h repeaterName:port [-n net] [-p port]

Where:

Exiting the NetTunneler

The NetTunneler can be exited by either entering the Ctrl-C keystroke sequence in the terminal window in which the NetTunneler command was entered or by closing the terminal window that was brought up when the NetTunneler icon was selected.

Sender

The Sender tool is used to capture and transmit audio and/or video to one or more destination on a network. The audio and/or video data is formatted and transmitted on the network using the Real-Time Transport Protocol (RTP) Version 2.0 Internet Draft specification. Currently, audio data is only encoded for transmission using the PCMU encoding format. Likewise, video data is only encoded using the H263, H261, or MJPEG encoding format.

To learn more about the Sender, see:

• Starting the Sender
• Sender Main Window
• Sender Connections Window
• Sender Add Connection Window
• Sender Settings Window
• Sending a Broadcast

Starting the Sender

The Sender can be started either by entering a command on the command line, or by selecting either of the UMSTVSender or UMSRadioSender icons located in the Multimedia folder of desktop's Application Manager. As the names imply, the UMSTVSender icon is used to broadcast audio and video data, and the UMSRadioSender icon is used just to broadcast audio. Both of these icons invoke the Sender tool, but with different parameters to cause the difference in operation. The following command line parameters are accepted by the Sender.

To start the Sender, type:

sender [-address address] [-alias alias] [-audioonly | -videoonly]

[-audioconnector cn] [-audioformat fmt] [-bitrate rate] [-help] [-id identifier]

[-interface interface] [-port port] [-sendheight height] [-sendwidth width]

[-ttl ttl] [-videoconnector cn] [-videoformat fmt] [-videosignal signal]

Where:

alias_name:
     Interface interface
     Address   address
     Port      port
*NEXT:
     Interface interface
     Address   address
     Port      port

Radio_Broadcast:
    Interface  "tr0"
    Address    "226.0.0.0"
    Port       "5004"
*NEXT:
    Interface  "tr0"
    Address    "129.71.86.14"
    Port       "6008"

LINE_IN
HIGH_GAIN_MIC
LOW_GAIN_MIC

Parallax Adapter:
   INPUT_COMPOSITE_1
   INPUT_COMPOSITE_2
   INPUT_YC_1
   INPUT_YC_2
850 Portable Workstation or
S15 Video Capture Adapter
   INPUT_COMPOSITE
   INPUT_SVIDEO
   INPUT_CCDCAMERA
ULTIMEDIA Video Capture Adapter
   INPUT_COMPOSITE
   INPUT_SVIDEO

H263
H261
MJPEG

NTSC
PAL
SECAM

Sender Main Window

The Sender Main Window figure contains a menu bar with three menus. Below the menu bar is the video monitoring window (unless -audioonly is specified at startup) and the station identifier along with audio monitor controls (unless -videoonly is specified at startup).

The menus on the menu bar are:

Sender Connections Window

See the Connections Window figure for the Sender. It is used to set, delete, or display the network connection parameters. If these parameters are not specified on the command line, this dialog box must be used to specify at least one connection before the sender will start to transmit data. The connections window contains a three-column scrolled list that displays the active network connections. Connections may be added or deleted from this list by using the buttons below the list:

Sender Add Connection Window

The Add Connection Window figure is used to add a connection to the list of active connections in the Connections Window. The following connection parameters are required:

In addition to the connection parameters this window contains the following buttons:

Sender Settings Window

The Settings Window is used to set, view, or alter the current Sender settings.

In addition to the connection parameters, this window contains the following buttons:

Sending a Broadcast

The following steps are required to send a broadcast:

1. Start the Sender. If the broadcast is to be a radio (audio only) broadcast, either select the UMSRadioSender icon or start the Sender from the command line with the -audioonly flag. Otherwise, select UMSTVSender or start the Sender from the command line without the -audioonly flag to broadcast audio and video. If you are starting the Sender from the command line, you can also specify any other desired parameters using the syntax described in the "Starting the Sender" .
2. Use the Audio and/or Video pull-down menus under the Options menu choice to select the desired audio and/or video connectors, formats, and so on.
3. Use the Identifier option from the Options menu to set the "Station Identifier" string for this broadcast.
4. Select the Connections option from the Options menu to bring up the Connections Window.
5. Select the Load button to load a predefined group of connections as identified by an alias in the .UMS_config file or select the Add button to add connections one at a time. As soon as the first connection is made, the Sender begins broadcasting. Connections may be added or deleted as desired while the sender is running. When you have finished adding or deleting connections, select the Done button.
6. When the broadcast is finished, select Exit from the File menu to end the broadcast.

Receiver

The Receiver tool is used to monitor incoming audio and/or video data from one or more sending source on a network. The format of the data must conform to the Real-time Transport Protocol (RTP) Version 2.0 Internet Draft specification. Additionally, only PCMU-encoded audio data and H.263, H.261, and MJPEG encoded video data are currently accepted by the Receiver.

This section contains information about:

• Starting the Receiver
• Receiver Main Window
• Receiver Monitor Window
• Receiver Connection Parameters Window
• Receiver Connect Window
• Receiving a Broadcast

Starting the Receiver

The Receiver can be started either by entering a command on the command line or by selecting either of the UMSTV or UMSRadio icons located in the Multimedia folder of desktop's Application Manager. As the names imply, the UMSTV icon is used to receive audio and video data, and the UMSRadio icon is used to just receive audio. Both of these icons invoke the Receiver tool, but with different parameters to cause the difference in operation. The following command line parameters are accepted by the Receiver.

To start the Receiver, type:

receiver [-address address] [-audioonly] [-autoaccreq] [-help] [-interface interface] [-nomainbox seconds] [-port port]

Where:

Receiver Main Window

The Main Window for the Receiver contains a menu bar with three menus and a list of sources currently attached to the Receiver. The menus on the menu bar are:

Receiver Monitor Window

The Monitor Window for an incoming data source plays the audio being sent from the source and also plays video if the source is sending video and the -audioonly flag was not specified. The Monitor Window has the following menus:

Also included on the Monitor Window is a source identifier window. This window contains the text Unknown until the sending source sends out its identifier. At this point, the source identifier window is updated.

There are two additional controls on the Monitor Window:

Receiver Connection Parameters Window

The Receiver Connections Parameters window is used to set, display, or alter the network connection parameters. If the parameters were not specified on the command line, this dialog box must be used to specify the connection parameters to establish the connection to the network. If a connection already exists, this window can be used to view or alter the connection parameters (if the Disconnect button is selected first).

In addition to the connection parameters, this window contains the following buttons:

Receiver Connect Window

The Connection Request window displays when a new source is attempting to connect to the Receiver. With the buttons in this window, you can choose to accept or reject the connection. If the source is unidentified, you can choose to have the receiver wait until it is identified before you are reprompted to accept the connection. The buttons are:

Receiving a Broadcast

Follow these steps to receive a broadcast:

1. Start the Receiver. If the broadcast being sent is radio (audio only), or if you only want the audio portion of the broadcast, either select the UMSRadio icon or start the Receiver from the command line with the -audioonly flag. Otherwise, select the UMSTV icon or start the Receiver from the command line without specifying the -audioonly flag to receive both audio and video. If you are starting the Receiver from the command line, you also can specify any other desired parameters using the syntax described in "Starting the Receiver" .
2. Specify the connection parameters. If the connection parameters were specified on the command line, the Receiver automatically attempts to make the specified connection and start if successful. If the connection parameters were not specified on the command line, they must be supplied in the Connection WIndow before the Receiver starts to receive data. If the Receiver was started with the -nomainbox option and the connection parameters were not specified on the command line, the Connection Window automatically displays when the Receiver is started. You can then enter the connection parameters. If you did not specify the -nomainbox option, use the Connections option on the main window's Options menu to bring up the Connections window and enter the desired connection parameters.

   Note: Only one Receiver on a system is started for any given combination of connection parameters. If more than one Sender is sending data to the same connection parameter combination, the Receiver automatically adds new Monitors for the additional data sources as needed or allowed. See step three for information on choosing which data sources to accept.

3. If the -autoaccreq option was not specified, as data from each source sending data to the specified connection parameters is received, the Receiver displays the Connect window to notify you that data from a new source has arrived. This allows you to decide if you want to receive the data from the sending source or have the receiver throw the data away. Because more than one Sender might be sending data to the same connection parameters, this feature lets you select which Sender's data to receive.
4. If a Monitor window is closed before the Receiver exits, the Monitor enters into a suspended mode (unless the -nomainbox option is specified at startup). Once suspended, you can reactivate the Monitor window by selecting the ID of the suspended Monitor in the list of sources located in the main window. Once you select a suspended ID, the Activate option of the Main Window's Option menu becomes available.
5. Select the Activate option to reactivate the Monitor window.