Secure Global Desktop 4.40 Administration Guide > Applications, Documents, and Application Servers > Enabling Sound in X Applications

Enabling Sound in X Applications

Secure Global Desktop Administrators can enable sound in X applications accessed using SGD. You enable sound in X applications as follows:

1. Configure the application server.
2. Configure the client device.
3. Configuring the X application.
4. Enable the SGD UNIX audio service.

Configuring the Application Server

To be able to hear sound in an X application, you must install and run the audio module of the SGD Enhancement Module on the application server.

Note If you are using zones on Solaris OS platforms, the audio module must be installed in the global zone.

See the Secure Global Desktop Installation Guide for instructions on installing the audio module. If you did not install the audio module when you installed the Enhancement Module, you must uninstall the Enhancement Module and install it again.

If the audio module is installed, you start the audio service with the install_dir/bin/tem startaudio command. By default, install_dir is /opt/tta_tem. You must be superuser (root) to use this command.

The audio module installs the SGD audio daemon and audio driver emulator.

Note As the audio module includes an audio driver emulator, the application server itself does not actually need to have a soundcard.

The audio daemon supports the following audio data formats:

• u-law and A-law with 8-bit precision
• 16-bit linear Pulse-code modulation (PCM)

The audio daemon supports any sample rate from 8000Hz to 48 kHz for one or two channels. The audio daemon uses the sample rate specified by the UNIX audio quality attribute on the Global Settings » Client device tab in the SGD Administration Console. By default, the sample rate is 22.05kHz.

The SGD audio daemon connects to the SGD server on random ports. If there is a firewall between the application server and the SGD server, the firewall must allow connections on all ports from the application server to the SGD server.

On Linux platforms, the audio driver emulator requires the soundcore module in the kernel. The audio driver emulator is an Open Sound System (OSS) emulator.

Configuring the Client Device

To be able to hear sound in an X application, the client device must be capable of playing sound.

Users with Solaris Operating System (Solaris OS) or Linux client devices must also have read and write access to the following audio devices:

• The /dev/audio device on Solaris Operating System (Solaris OS) platforms
• The /dev/dsp device on Linux platforms

Audio mixing on the client device is supported. On Solaris OS workstations, Microsoft Windows and Mac OS X client devices, the client hardware performs the mixing. On Linux and SunRay client devices, the Enlightened Sound Daemon (ESD or EsounD) is required to perform mixing.

Configuring the X Application

To be able to hear sound in an X application, the X application might have to be configured to output sound using the right audio device and audio format.

Some X applications are hard-coded to use the /dev/audio or /dev/dsp devices for audio output. You can enable an SGD audio redirection library to force the X application to use the device specified by the SGDAUDIODEV environment variable. To enable the audio redirection library:

1. In the SGD Administration Console, click the Applications tab and select the X application.
2. Click the Client Device tab.
3. Select the Audio Redirection Library check box.
4. Click Save.

Alternatively, use the following command:

$ tarantella object edit --name obj --unixaudiopreload true

The SGD audio driver emulator is an OSS driver. The X application might have to be configured to use OSS. If your system uses the Advanced Linux Sound Architecture (ALSA), you might have to enable the ALSA OSS emulation modules in the kernel.

If the Connection Method (--method) used for the X application is SSH and the application's Window Type (--displayusing) is Kiosk, the Session Termination (--endswhen) attribute must be set to Login Script Exit or No Visible Windows (loginscriptnowindows).

Enabling the SGD UNIX Audio Service

To be able to hear sound in an X application, the SGD UNIX audio service must be enabled in the array. The UNIX audio service is disabled by default.

You enable the UNIX audio service as follows:

1. In the SGD Administration Console, click the Global Settings » Client Device tab.
2. Select the UNIX audio check box.
3. Click Save.

Alternatively, use the following command:

$ tarantella config edit --array-unixaudio 1

Note The audio service only takes effect for new user sessions. Users must log out of SGD and log back in again to enable sound in their X application sessions.

You can also set the audio quality. The default is Medium Quality Audio (sample rate 22.05kHz). Only change this setting if you experience problems with audio quality.

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