By Product Desktops Technical Guides VMware Horizon

Flash URL Redirection in VMware Horizon View

By Judy Wu, Solution Engineer, End-User Computing, VMware

Flash URL Redirection intercepts and redirects a ShockWave Flash (SWF) file from a virtual desktop to the client endpoint. With this feature, multicast and unicast video streams within a VDI desktop can be sent directly from the media source to the endpoints, bypassing the virtual desktops. Both performance and user experience are improved, while resource usage is reduced.

Flash URL Redirection was first released in VMware Horizon View 5.2 Feature Pack 2, but only the multicast stream was supported. With Horizon View 5.3 Feature Pack 1, the unicast stream is also supported. The following table tells you clearly what is supported in each version.

Horizon View 5.2 + FP2*1

Horizon View 5.3 + FP1

View Client 2.2

Windows View Client 5.4*2 / Linux View Client 2.1

View Client 2.2

Windows View Client 5.4 / Linux View Client 2.1

Flash URL Redirection – Multicast Stream Y Y Y Y
Flash URL Redirection – Unicast Stream N N Y N

*1: FP stands for Feature Pack

*2: The Windows View Client 5.4 is the old Windows View Client. In the Q4 2013 client release, we are shipping a new Windows Client. This client is based on a common code base with the other clients. Therefore, to align Windows Clients with all other clients, the Windows Client version has changed from 5.4 to 2.2, and version 2.2 is newer.

Supported environment for Flash URL Redirection


  • IE8, IE9, IE10
  • Firefox 20.x
  • Chrome 26.x
  • Other browsers may work too, but we have not explicitly tested them

VDI desktop OS:

  • Windows 7, 32- or 64-bit
  • Windows 7 SP1, 32- or 64-bit

View Client OS:

  • Windows XP/Vista/7/8/8.1
  • Ubuntu 10.04
  • Other Windows or Linux operating system versions may work too, but we have not explicitly tested them.

Protocol: PCoIP

Installation and configuration for Flash URL Redirection

There are three main steps to make sure the Flash URL Redirection feature runs smoothly:

  1. Make sure that Flash URL Redirection is installed and enabled in the virtual desktop and View Client.
  2. Configure the MIME HTML (MHTML) Web pages that provide links to the multicast or unicast streams. Users display these Web pages in browsers on their virtual desktops to access the video streams.
  3. Make sure that the ViewMP service is started in a PCoIP session.


To install Flash URL Redirection, install Feature Pack 1 on Horizon View 5.3 or Feature Pack 2 on Horizon View 5.2, and select Flash URL Redirection.

Configuration on Adobe Media Server

Users will access particular Web pages from browsers on their virtual desktops to access the multicast/unicast streams. To make the redirection work, special configurations should be added into these MHTML web pages.

Embed the viewmp.js JavaScript command in the MHTML Web page in Adobe Media Server, after the swfobject.js include line. For example:

    <script type=”text/javascript” src=”swfobject.js”></script>

    <script type=”text/javascript” src=”http://localhost:33333/viewmp.js”></script>

For embedding Flash Player content using SWFObject dynamic publishing section, refer to step 3 in the swfobject documentation. For parameters for Strobe Media Playback, refer to Basic Configurations and Advanced Configurations in the Adobe documentation on configuring the Player.

Customize the Flash URL Redirection error message and content that is sent to end users. This is optional. For example:

    var vmwareScriptErrorMessage=”localized error message”var vmwareFlashContentHTML=”<h1>Thank you for choosing VMware. The video is being redirected to a new window.</h1>”

Starting the ViewMP service

After a PCoIP session to a VDI desktop has been set up, verify that the ViewMPServer.exe process is running on the desktop.

Testing Flash URL Redirection

Now, when everything is ready, redirection of a video stream from VDI desktops to endpoints will work. Open a browser and input the configured MHTML Web page. A window titled Flash Media Projector will open on the endpoint. The window was called Multicast in Windows Client 5.4 and Linux Client 2.1.



VMware Horizon View 5.3 Documentation
VMware Horizon View Clients Documentation


VMware Horizon View
VMware Horizon View Clients

That’s it from me for this time. I’ll write again in the future when we have further improvements and enhancements to report. Please provide feedback or send questions about Flash URL Redirection either at the bottom of this blog, or via the VMware Horizon View Community site.