Using the Real-Time Audio-Video Feature for Webcams, Microphones, and Speakers

If an administrator has configured the Real-Time Audio-Video feature, you can use the client machine's audio-video devices in a remote desktop or published application. Real-Time Audio-Video is compatible with standard conferencing applications and browser-based video applications, and it supports standard webcams, audio USB devices, and analog audio input.

Overview of Real-Time Audio-Video

Real-Time Audio-Video is supported only in Chrome, Microsoft Edge, and Firefox. The default video resolution is 320 x 240 pixels. The default Real-Time Audio-Video settings work well with most webcam and audio applications.

Note: Browsers on iOS do not support Real-Time Audio-Video.

For information about changing the Real-Time Audio-Video settings, see "Configuring Real-Time Audio-Video Group Policy Settings" in the Horizon Remote Desktop Features and GPOs document.

When a remote desktop or published application is connected to the client machine's audio-video device, before the remote desktop or published application can use the device, the browser might ask for permission. Different browsers behave differently.

Microsoft Edge asks for permission every time. You cannot change this behavior. For more information, see https://blogs.windows.com/msedgedev/2015/05/13/announcing-media-capture-functionality-in-microsoft-edge.
Firefox asks for permission every time. You can change this behavior. For more information, see https://support.mozilla.org/en-US/kb/permissions-manager-give-ability-store-passwords-set-cookies-more?redirectlocale=en-US&redirectslug=how-do-i-manage-website-permissions.
Chrome asks for permission the first time. If you allow the device to be used, Chrome does not ask for permission again.

When a remote desktop is connected to the client machine's audio-video device, an icon for each device appears at the top of the sidebar. A red question mark appears over the device icon in the sidebar to indicate the permission request. If you allow a device to be used, the red question mark disappears. If you reject a permission request, the device icon disappears.

If Real-Time Audio-Video is being used in a remote desktop or published application session and you open a connection to a second remote desktop or published application, and if a security warning appears (for example, if a valid certificate was not installed), ignoring the warning and continuing to connect to the second remote desktop or published application causes Real-Time Audio-Video to stop working in the first session.

Improving Real-Time Audio-Video Performance

When using Real-Time Audio-Video with certain data-intensive applications, such as video conferencing applications, you might encounter a lag in performance. To improve performance, you can enable the H.264 codec for Real-Time Audio-Video. You can also specify whether to use hardware acceleration for Real-Time Audio-Video.

HTML Access Web client uses the Opus audio codec to handle a wide range of audio applications, including Voice over IP, videoconferencing, and so on. To improve the real-time audio performance, you can set the Opus codec on the HTML Access Web client.

The following sections describe how to configure these settings to improve Real-Time Audio-Video performance.

Enable the H.264 Codec for Real-Time Audio-Video

H.264 is an industry standard for video compression, which is the process of converting digital video into a format that takes up less capacity when it is stored or transmitted.

To support H.264 for Real-Time Audio-Video, your client device must be running the Chrome or Microsoft Edge browser.

Log in to the Horizon Connection Server host machine with administrator privileges.
Navigate to the Server/broker/webapps/portal/WEB-INF/classes directory.
Open the portal-version.properties file in a text editor.
Ensure that the following property/value entry appears in the file.
```
enableRTAVH264Codec = true
```
- Setting the value to true enables H.264 for Real-Time Audio-Video. This is the default value.
- Setting the value to false deactivates H.264 for Real-Time Audio-Video.
Save and close the portal-version.properties file.

Configure Hardware Acceleration for Real-Time Audio-Video

Real-Time Audio-Video hardware acceleration works on your client only if the graphics processing unit (GPU) is supported on your device and is compatible with FFmpeg.

Enabling hardware acceleration can improve performance, but it can also result in feature limitations under certain use cases. A configuration setting lets you turn on or off hardware acceleration for Real-Time Audio-Video as needed.

Log in to the Horizon Connection Server host machine with administrator privileges.
Navigate to the Server/broker/webapps/portal/WEB-INF/classes directory.
Open the portal-version.properties file in a text editor.
Ensure that the following property/value entry appears in the file.
```
hardwareAccelerationOption = <VALUE>
```
where takes one of the following valid values:
- no-preference allows the client flexibility to use either hardware acceleration or software acceleration, based on what is optimal for the system and configuration. This is the default value.
- prefer-hardware turns on hardware acceleration.
- prefer-software turns off hardware acceleration and uses software acceleration instead.
Save and close the portal-version.properties file.

Enable Discontinuous Transmission Mode

Discontinuous transmission (DTX) mode provides a solution where there is a huge reduction in the audio traffic when the participant is silent. The reduction in audio traffic occurs as the audio packet is not transmitted. To enable Discontinuous Transmission mode, perform the following steps:

Login to the connection broker with your admin account.
Naviagte to Server\\broker\\webapps\\portal\\WEB-INF\\classes path.
Open portal-version.properties file.
Add enableRTAVDTX: "true" to enable real-time audio video discontinuous transmission mode or set enableRTAVDTX: "false" to disable real-time audio video discontinuous transmission mode.

Note: By default, enableRTAVDTX is always set to true.

Select a Preferred Speaker

With the Real-Time Audio-Video feature, if multiple speakers are connected to the local client system, only one of the speakers is used in the remote desktop or published application. To specify which speaker is preferred, you can configure Real-Time Audio-Video settings in HTML Access.

If it is available, the preferred speaker is used in the remote desktop or published application. If the preferred speaker is not available, another speaker is used.

Prerequisites

Verify that a speaker is installed and operational on the local client system.
Connect to a server.

Procedure

Click the Settings toolbar button in the upper-right corner of the desktop and application selector window and scroll down to the Real-Time Audio-Video settings.
From the Preferred speaker drop-down menu, select a preferred speaker.

Selecting All allows you to use multiple speaker redirection, as described in Using Multiple Speakers.

Results

The next time you start a remote desktop or published application, the preferred speaker that you selected is redirected to the remote session.

Using Multiple Speakers

If more than one speaker is connected to the client computer, and the remote desktop supports multiple device redirection with the speaker feature, you can use all the speakers connected to the client computer in the remote desktop.

For administrators - this feature is supported only with virtual desktops. It is not supported with published desktops or published applications.

For end users - whether you can use more than one speaker depends on how a Horizon administrator has configured the remote desktop. To use this feature, you must select All for the preferred speaker setting. For more information, see #.

Observe the following tips for using more than one speaker with device redirection.

When you connect to a remote desktop, all speakers currently connected to the client computer are redirected.
By default, the remote desktop uses the speaker that is configured as the client default speaker. You can switch to have the remote desktop use any speaker connected to the client computer.
If you disconnect a speaker from the client computer, and the speaker is not being used in an application in the remote desktop, the speaker device is deleted from the remote desktop after you log out and log back in to the desktop. If the speaker is being used by an application in the remote desktop, the speaker device is deleted after the application releases it.
The display name of a redirected speaker is the actual device name, but with (VDI) appended, for example, Acme Speaker (VDI).
You can use multiple redirected devices simultaneously in a remote desktop.

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