How to troubleshoot “Devices” tab missing from Windows Receiver toolbar after connecting a Linux VDA

root@XXXX:# modinfo /opt/Citrix/VDA/lib64/usb-vhci-hcd.ko

filename: /opt/Citrix/VDA/lib64/usb-vhci-hcd.ko

……

description: USB Virtual Host Controller Interface driver

srcversion: 9E700B46FBDA1647A9A2865

depends:

vermagic: 4.4.0-45-generic SMP mod_unload modversions

Note: In above example, Linux kernel version is inconsistent with VHCI Module.

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Cisco IOS XE Software IOx Guest Shell USB SSD Namespace Protection Privilege Escalation Vulnerability

A vulnerability in the file system on the pluggable USB 3.0 Solid State Drive (SSD) for Cisco IOS XE Software could allow an authenticated, physical attacker to remove the USB 3.0 SSD and modify sensitive areas of the file system, including the namespace container protections. 

The vulnerability occurs because the USB 3.0 SSD control data is not stored on the internal boot flash. An attacker could exploit this vulnerability by removing the USB 3.0 SSD, modifying or deleting files on the USB 3.0 SSD by using another device, and then reinserting the USB 3.0 SSD on the original device. A successful exploit could allow the attacker to remove container protections and perform file actions outside the namespace of the container with root privileges.

Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.

This advisory is available at the following link:
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iox-usb-guestshell-WmevScDj

Security Impact Rating: Medium

CVE: CVE-2020-3396

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XenApp/XenDesktop USB Citrix Tested Device List

This article provides information regarding the USB devices used to test the generic USB remoting feature.

Note: Devices displayed are verified and any extra information required to configure them is included, with any limitations.

For device not given in below list, please refer Citrix Ready Marketplace.

Devices tested with XenDesktop 7.11 with Citrix Receiver for Windows 4.5. (see attached PDF for XenDesktop 7.6):

Device Type Win7, Win8, Win8.1, Win 10 Windows Server 2008 R2 Windows Server 2012 R2/2016
Optimized (Default) Generic Optimized(Default) Generic Optimized(Default) Generic
Mass Storage Device (PenDrive, USB Harddisk) Yes Yes Yes Yes Yes
Audio Device (Headset, Speaker) Yes Yes Yes Yes Yes
Webcam Device (Video Camera) Yes Yes Yes Yes Yes
SmartCard Readers * Yes Yes Yes
Keyboard * Yes Yes Yes Yes Yes
Mouse * Yes Yes Yes
3D Mouse Yes Yes
Scanner Yes Yes Yes Yes
Printer Yes Yes Yes Yes Yes
Phones (iOS) Yes Yes
Phones (Android) Yes Yes
Tablets (iOS)(Test with Ipad mini, Ipad3) Yes Yes
Tablets (Android) Yes Yes
Signature Pads (Wacom/Topaz) Yes Yes
Wacom Tablets Yes
DVD-Writer Yes Yes Yes Yes
USB 2.0 /3.0 hubs

Notes:

  • *Are restricted for usb redirection by GPO (recommended settings) Hub as a device is not redirected to VDA, however any devices plugged into hub will redirect seamlessly Modem Devices are blocked by the default policy MTP mode for Samsung devices gets policy restricted due to modem exposure to client.
  • Phones and Tablets are optimized by “Client USB Plug and Play device redirection” policy which is by default enabled for Windows Server OS only

For Server OS

The USB client drivers must be compatible with RDSH for Windows 2012 R2.

Non fully virtualized device such as Smart Card Reader has no USB support because these devices utilize the dedicated service running for session 0 (first session) on Windows Server VDA.

Mass Storage for Server OS is supported from 7.11 VDA.

Audio Device for Server OS is supported from Receiver 4.5 and VDA 7.8.

Encrypted USB redirection and Bitlocker to go devices are currently not supported with Server OS.

Device List

Overview of generic USB redirection support by USB device type (Virtual Delivery Agent for Desktop or Server OS).

Serial Number Make Model Notes/Comments
Mass Storage: For Server OS supported from 7.11 and safe eject from taskbar for server OS is not supported currently]
1 Sandisk 1GB Cruzer Micro U3 U3 autorun and eject features do not work within a xendesktop session
2 Sandisk 4GB Titanium U3 U3 autorun and eject features do not work within a xendesktop session
3 Sandisk MicroSD Card Reader (2Gb, 8Gb xD tested)
4 SanDisk 2GB Extreme III Compact Flash
5 Sandisk SDCZ64096A1 4GB Cruzer Micro with U3 Technology U3 autorun and eject features do not work within a xendesktop session
6 SanDisk SDCZ50 4G
7 SanDisk Cruzer Micro Skin 2GB
8 Kingston 1GB USB 2.0 Migo Personal
9 Kingston 1GB Secure Digital Flash Card
10 Kingston Data Traveller Mini
11 Kingston 4GB DataTraveler
12 Seagate USB Hard drive ST305004exd (1TB)
13 Seagate USB 3.0 Hard Drive 1TB (Sno. 122B657IM)
14 Lexar 1GB Flash Drive
15 Lexar USB Dongle (xD Card)
16 Lexar 2GB Jump drive
17 Lexar USB flash memory stick
18 Laguna USB device (CDROM + Flash drive/U3)
19 Trust 7 in 1 Card reader
20 Sumvision 3.5″ USB2.0 & eSATA enclosure
21 Corsair Flash Voyager 16 GB (Corsair)
22 FujiFilm xD-Picture Card 512MB
23 ioMEga Floppy plus 7-in-1 Card Reader Device drivers must be installed with an administrator privilege prior using this device.
24 PC Line PCL-EFD2X 3 1/2 Floppy Drive
25 Freecom FS-50 DVD +/- RW Does not work for Server OS
26 LaCie D2 Blu-Ray BluRay playback not supported over a network connection.
27 LG BE06 Blu-Ray/HD Player Super Multi Blue BluRay playback not supported over a network connection.
28 Microsoft 32MB Flash Drive
29 Belkin 256MB Mass Storage Device
30 Buffalo DVSM-PN58U2VB Device drivers must be installed with an administrator privilege prior using this device.
31 Lenovo USB2.0 memory stick
32 Transcend 16GB JetFlash 700 USB 3.0 Flash Drive
33 SSK USB3.0 8G/SFD201
34 Netac USB3.0 U903 8G
35 SAMSUNG SE-218CB DVD Writer Does not work for Server OS
36 SafeStick flash drive BLOCKMASTER BM9930
WebCams
1 Microsoft VX1000 LifeCam
2 Microsoft Lifecam VX-7000 The preview of video in Lync 2010 shows a black screen if device is connected to USB 3.0 port.
3 Microsoft Lifecam HD-3000
4 Logitech HD Pro C920 Sometimes, the device may appear in “Drives and Printers” on client even after launching a VDA session
5 Logitech C110
When a device is connected to VDA through the client, Sleep or hibernate action may be delayed on the Client machine.
6 Logitech QuickCam Pro 9000 Within session CPU usage might be high, when webcam is rediected to the VDA Session
7 Creative VF0520
8 Creative Live! Cam Notebook Webcam
9 Teclast TL-T838-NDE2S
10 Webcam Pro 9000
Incorrect webcam name may be shown in Devices tab in the Perference window.
11 HP True Vision Integrated webcam
Headsets/Speakers: [For Server OS enable audio through Generic USB from client policy, supported from Receiver 4.5 and XenApp / XenDesktop 7.8 ]
1 Logitech H330 (USB Headset)
2 Logitech S150 (USB Speakers)
3 Logitech H340 (USB Headset)
Audio experience may be unclear with Logitech H340 inside session
4 Plantronics Blackwire C435-M
5 Plantronics Blackwire C310-M
6 Plantronics Voyager Legend UC + BT300 (Bluetooth Headset + Bluetooth USB Adapter)
7 Plantronics Blackwire C320-M
8 SALAR KX235 USB headset-USB 2.0
HID style devices
1 Wacom Bamboo Fun A6 Wide Tablet Mouse class device. Blocked by default policy
2 Wacom Bambo One Mouse class device. Blocked by default policy
3 Wacom Bamboo touch tablet Mouse class device. Blocked by default policy
4 Bloomberg FreeBoard To use Bloomberg (Message) Key, Bloomberg Audio redirection has to be enabled.

If fingerprint scanner operation fails with high latency, then ICA custom channel has to be created for the scanner.
5 Bloomberg Starboard Requires two cables to be attached and for Server OS, enable Audio through Generic USB through the Client Policy
5 Vernier GoTemp Temperature Sensor
6 Vernier GoLink Multi Sensor
7 Kensington Orbit Mouse class device. Blocked by default policy
8 Microsoft Sidewinder X5 Mouse class device. Blocked by default policy, Requires Fingerprint driver locally
9 IBM KB with fingerprint reader Mouse class device. Blocked by default policy
Print/Scan Devices
1 Lexmark USB printer 800 series
2 Lexmark Multifunction USB printer scanner 1200 series
3 Canon Pixma MP620 -Multi Function Printer/Scanner
4 Canon iP5300 Printer
5 Canon CanScanLiDE 700F
6 Canon Lide 25 Colour Flatbed Scanner
7 Cannon Canon Pixma MP648
8 Canon CanoScan LiDE 110
9 HP ScanJet G3010
10 HP LaserJetP2014
11 HP DESKJET 2000
12 Epson Stylus DX4400 – multifunction AIO Printer/Scanner/Copier
13 WASP WCS3905 CCD barcode Scanner (USB) Displayed as a HID device, hence blocked by the default policy.
14 HP ScanJet Pro 3000S2 Twain 2.0 driver needs to be installed on client (Supported from 7.11)
Phone/PDA
1 Blackberry Pearl
2 Blackberry 8820
3 Blackberry 8320
4 Blackberry Curve 8900
5 Blackberry Curve 8520
6 Blackberry Curve 8900
7 Nokia N73 Mass storage mode working, PC Suite mode not available
8 Nokia N95 Mass storage mode working, PC Suite mode not available
9 Nokia 9500 Communicator Device can be visible on Receiver Toolbar by enabling the policy, but the device cant be redirected to the VDA session
10 HTC Tattoo
11 HTC Touch
12 Apple iPhone 3G Customers are not recommended to restore or upgrade the firmware on any Apple device. Device will remain in Restore mode until recovered on a physical machine.
13 Apple iPhone5 Customers are not recommended to restore or upgrade the firmware on any Apple device. Device will remain in Restore mode until recovered on a physical machine.
14 Polycom CX200 (Desktop Phone)
15 HP iPAQ 4150
16 Samsung Galaxy 4 MTP mode for samsung devices gets policy restricted due to modem exposed to client
17 Samsung Galaxy Core 2 MTP mode for samsung devices gets policy restricted due to modem exposed to client
18 Samsung Tablet MTP mode for samsung devices gets policy restricted due to modem exposed to client
HUBS: [Hubs are not supported as devices themselves however devices plugged into hubs work seamlessly]
1 Belkin 4-Port USB 2.0 Flex Hub
2 Plexus High Speed USB2.0 7 Port Powered Hub
3 Logitech 4 Port USB Hub
4 Dlink Dub-H4 USB 4 Port Hub
5 Belkin USB 2.0 4-Port Mini Hub
6 Belkin USB 4 PORT SLIM HUB (USB1.1)
7 Startech ST4202USBGB
8 Belkin 4-Port USB 2.0 Flex Hub
MODEM: [Modem Devices are blocked by the default policy]
1 LM Technologies Bluetooth EDR USB adapter
2 Trust USB Bluetooth Adaptor
3 Trust 56K USB Modem MD-1270
Security Devices
1 Microsoft Fingerprint Reader Win USB Only works with a local account and its known limitation of the vendor software
Digital Cameras
1 Canon PowerShot S70
2 Canon EOS 300D/Digital Rebel (Mass Storage)
3 Canon EOS 300D/Digital Rebel (PTP Mode)
4 Canon EOS 450D
5 Canon Ixus v3
6 Ricoh Capilio 500G Wide (Mass Storage)
7 Ricoh Capilio 500G Wide (Original Mode)
8 Nikon D70s (Mass Storage)
9 Nikon D70s (PTP Mode)
10 Fuji FinePix F31fd
Apple Devices: [ Customers are not recommended to restore or upgrade the firmware on any Apple device. Device will remain in Restore mode until recovered on a physical machine.]
1 Apple iPod Touch (16GB)
2 Apple iPod Shuffle (2GB)
3 Apple iPod Nano Ejecting an iPod Nano from within iTunes can take up to 3 minutes.
Other devices
1 Nipco USB Missile rocket launcher
2 Dictaphone Foot Control USB adapter
3 3DConnexion Space Navigator
4 3DConnexion Space Pilot Pro
5 3DConnexion Space Explorer
6 Startech SVID2USB2
7 Aigo DPF5170 (USB photo frame)
8 Plantronics Calisto 619 (Bluetooth Wireless Speakerphone + Bluetooth USB Adapter )
9 D-Link DBT-122 (Wireless USB Bluetooth Adapter)
10 Buffalo DVSM-PN58U2VB (USB DVD-RW) Does not work for Server OS
11 Wacom Signature Pad STU430 , STU 530
12 Wacom Tablet Intuos Pro Not supported for Server OS
13 Wacom interactive pen display DTU1031 Not supported for Server OS
14 Topaz Signature Pad T- LBK 460 Topaz driver is required on vda (if installation fails, extract driver package and then install driver Manually)
15 Philips Speech Mike Pro
USB host Controller for 3.0 port
1 Renesas Electronics USB 3.0 Host Controller Drivers
2 Microsoft USB Host Controller Drivers Supported from Windows 8 OS onwards.

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Information on Webcams in XenApp and XenDesktop

This article contains information about using webcams with Citrix Virtual Apps and Desktops (formerly XenApp and XenDesktop) and explains the HDX RealTime Webcam Video Compression and HDX Plug-n-Play Generic USB Redirection features.

In addition to the two approaches discussed in this article, it should be noted that “optimized” solutions are available for certain leading Unified Communications applications. These optimized solutions shift the media processing workload to the user device, thereby maximizing server scalability. Optimized solutions exist for Microsoft Skype for Business, Microsoft Lync 2013, Cisco Jabber for VDI, and Avaya one-X Communicator.

1. Background

Webcams can be used by applications running within the Citrix Virtual Apps and Desktops session either by HDX RealTime Webcam Video Compression or by using HDX Plug-n-Play technology. Users can choose between the two based on their specific requirements. HDX RealTime Webcam Video Compression is generally recommended since it offers superior bandwidth efficiency.

2. HDX RealTime Webcam Video Compression

With HDX RealTime Webcam Video Compression, the video data is captured on the user device; it is then compressed and sent to the XenApp/XenDesktop session. Installation of the device drivers for the webcam is not required on the Virtual Delivery Agent (VDA). Device drivers are only required on the client device. It is recommended that the latest drivers are obtained directly from the webcam manufacturer’s website (or use the driver CD that came with the webcam). Sometimes, default drivers are installed when the device is first plugged in, but these drivers might not offer the video color space that the client’s codec is looking for, which might lead to higher CPU consumption on the user device as a result of color space conversion.

Note: 64-bit Application support for HDX RealTime Webcam Video Compression requires XenApp / XenDesktop 7.17 or later, and also Receiver for Windows 4.11 or later

HDX RealTime Webcam Video Compression allows less bandwidth consumption and is especially suited to deployments where the VDA and client reside across slow networks. HDX RealTime Webcam Video Compression uses upstream bandwidth in the rage of 300-600 kbps (for CIF resolutions).

User-added image

Further information regarding configuration of HDX RealTime Webcam Video Compression is available on the Citrix documentation site – see HDX video conferencing and webcam video compression.

HDX webcam video compression requires that the following policy settings be enabled (all are enabled by default).

  • Multimedia conferencing
  • Windows Media Redirection


User-added image


High Definition

In XenDesktop 7.16 and XenApp 7.18 (with Receiver for Windows 4.10 or higher) support was added for native resolutions beyond 352×288 (CIF).

This enhancement allows high-def webcam native resolutions for virtual sessions, up to 1080p.

Citrix Receiver now queries the webcams on the client for their list of supported capabilities (media type information and resolutions). Then, the HDX PnP virtual channel is used to send this information to the VDA. Server will then offer this list to the hosted application trying to use the webcam.

Media types that aren’t supported will be filtered out and not offered to the application.

At the moment, HDX supports the RGB formats, YUV420 formats and YUY2 packed formats.

Application running on the VDA picks the desired media type and resolution from the list that was offered.

(If for some reason this media type negotiation fails, HDX falls back to our legacy way of webcam redirection, which is to use hard coded 352×288 resolution).

The selected media type and resolution is then sent to the client and the webcam uses that to start the webcam feed.

The existing registries keys on the client to control the resolution will be honored, and this mechanism can be utilized to enforce a given resolution (see section 7.1 below).

If Bandwidth consumption is a concern, High Definition can be disabled by applying the following registry key on the VDA:

HKEY_LOCAL_MACHINESoftwareCitrixHDXRealTime

Name: Enable_HighDefWebcam

Type: REG_DWORD

Data: 0 = Disable the high definition webcam streaming

3. HDX Plug-n-Play Generic USB Redirection

With HDX Plug-n-Play Generic USB Redirection technology, the webcam is virtually detached from the client device and attached to the XenApp/XenDesktop session. This provides all the native functionalities of the webcam in the XenApp/XenDesktop session. HDX Plug-n-Play Generic USB Redirection requires the device drivers for the webcam to be available on both the client device as well as on the VDA.

Bandwidth usage for webcams using HDX Plug-n-Play Generic USB Redirection technology can vary based on the vendor and model of the device, but it is significantly higher compared to use it over HDX RealTime Webcam Video Compression. HDX Plug-n-Play for webcams is recommended to be used only under LAN conditions where bandwidth and latency are not constraints.

Refer the following link regarding more information on HDX Plug-n-Play configuration:

Configure USB Support.

4. Default Behavior

By default, webcams use HDX RealTime Webcam Video Compression technology. However, end users can override the default behavior and explicitly choose to use HDX Plug-n-Play Generic USB Redirection from the Desktop Viewer preferences tab of Citrix Workspace app, if the administrator has enabled remoting of USB devices through policies.

4.1 Whether to use Webcam Video Compression or Generic USB Redirection

HDX RealTime Webcam Video Compression is the default and preferred way of using webcams with XenApp/XenDesktop, except when an “optimized” solution is available such as the HDX RealTime Optimization Pack for Microsoft Skype for Business and Lync. HDX RealTime Webcam Video Compression uses significantly less bandwidth compared to HDX Plug-n-Play Generic USB Redirection and works well over WAN connections.

HDX Plug-n-Play is recommended only when there are application compatibility issues with HDX RealTime Webcam Video Compression or when advanced native functionalities of the webcam such as auto-focus are required. For better performance, Citrix recommends a XenDesktop VDA to have at least two virtual CPUs.

4.2 Configuring HDX RealTime Webcam Video Compression

HDX RealTime Webcam Video Compression feature is available on XenDesktop 5.0 and later versions with Online Plug-in for Windows version 12.0 and later version or Receiver for Linux 12.0 and later version. It is also supported on Mac and Chrome Receivers.

HDX RealTime Webcam Video Compression is enabled by default on the VDA and on the Windows client and no additional configurations are required.

With Receiver for Linux, it has to be explicitly enabled. Refer the following link regarding information on how to configure this – Citrix Documentation – Optimize.

4.3 Dependency on Windows Media Redirection

HDX RealTime Webcam Video Compression uses the same underlying technology as Windows Media Redirection. Enable Windows Media Redirection in Studio for HDX RealTime Webcam Video Compression to be functional. If Windows Media Redirection is disabled, HDX RealTime Webcam Video Compression will not work.

4.4 Application Compatibility

HDX RealTime Webcam Video Compression is compatible with most unified communications clients. The feature has been tested for compatibility with the following applications:

  • Cisco Webex Meetings and Webex Teams
  • GoToMeeting
  • Google Hangouts and Meet
  • Microsoft Teams
  • Microsoft Skype for Business 2015, 2016 and 2019
  • Microsoft Skype 7 or higher
  • IBM Sametime
  • Adobe Connect
  • Media Foundation-based video applications on W8.x or higher and WS2012 R2 and higher (see section 8.5)


Note: 64-bit Application support requires XenApp / XenDesktop 7.17 or later, and also Receiver for Windows 4.11 or later, and Receiver for Chrome.

The 7.17 VDAs and 4.11 Receiver for Windows (or higher versions of both) now include both 64-bit and 32-bit H.264 compression encoder/decoders. This means customers using 64-bit video conferencing hosted applications, such as Skype for Business x64, Google Chrome browser, and Google Hangouts, are now supported. Note that these 64-bit video conferencing apps must support H.264 for this feature to work.

Some ARM Chromebooks don’t support H.264 encoding – in that case, only 32-bit apps in the VDA can use the optimized HDX RealTime Webcam Video Compression.

5. Webcam Compatibility

HDX RealTime Webcam Video Compression is not directly dependent on specific models of webcams. Any webcam that is DirectShow compatible (including integrated ones) can be used with HDX RealTime Webcam Video Compression. Most Windows Driver Model (WDM) compatible webcams can be used. However, webcam bandwidth consumption can vary from webcam to webcam. Different webcams offer different frame rates and have different levels of brightness and contrast. Citrix used the following webcams for initial feature validation:

  • Microsoft LifeCam VX models (2000, 3000, 5000, 7000)
  • Creative LIVE! CAM Optia Pro
  • Logitech QuickCam Messenger
  • Logitech C600, C920
  • HP Deluxe Webcam

During production testing, the LifeCam vx-3000 or later and the Creative Optia Pro gave the best results in terms of bandwidth consumed and subjective video quality. Adjusting the contrast of the webcam can reduce upstream traffic significantly. This can be accomplished if the webcam ships with a system tray utility that runs on the user device.


6. Known Issues

Caution! Refer to the Disclaimer at the end of this article before using Registry Editor.

  • If Citrix GoToMeeting with HDFaces or Skype for Business (either hosted or when in fallback mode with RTOP) does not recognize the webcam of the user, edit the system registry.

    For 32-bit devices, access HKEY_CLASSES_ROOTCLSID{860BB310-5D01-11d0-BD3B-00A0C911CE86}InstanceCitrix HDX Web Camera.

    For 64-bit devices, access HKEY_CLASSES_ROOTWow6432NodeCLSID{860BB310-5D01-11d0-BD3B-00A0C911CE86}InstanceCitrix HDX Web Camera.

    Add a string value named DevicePath.

    Set REG_SZ as the data type and Citrix Client as the value [Reference 263277].

  • HDX RealTime Webcam Video Compression does not automatically reconnect if the session connection is interrupted mid-conference. The user must restart the video conference [Reference 233296].

  • On XenApp 7.17 or older (RDS VDA), only one webcam can be used with HDX RealTime Webcam Video Compression at a time; if the client device has multiple webcams configured, only the first one successfully detected is used in the XenApp session. On XenDesktop (VDI), multiple webcams are supported, along with client-side webcam switching.
  • XenApp 7.18 added support for multiple webcams. Applications dynamically detect a webcam being plugged in or removed on the client. Users don’t have to restart the application to detect these changes.
  • In XenApp 7.18 or higher, actual webcam names are displayed instead of the generic Citrix HDX Camera (which is the way they are displayed in 7.15 LTSR, for example)

Double Hops:

  • Xenapp 7.15 LTSR and double hops – [internal ref. LD1143] when installing Citrix Receiver 4.10 or higher, or any version of Citrix Workspace app in the VDA, webcam functionality will break if H264 encoding is used. Only Citrix Receiver for Windows 4.9 LTSR can be installed in a 7.15 VDAs for H264 encoding. This is because both Receiver/Workspace app and the VDA rely on (and are packed with) the same codec library (CtxVideoCodec.dll), and installing Receiver/Workspace app in the VDA will overwrite the dll of the VDA. As a work-around (if you must install 4.10+ or Workspace app in the VDA), you can try to disable H.264 encoding, and enable Theora using the following registry setting (on the client or on the VDA)
i. HKEY_CURRENT_USERSoftwareCitrixHdxRealTime

DWORD EnableDeepcompress_Client – set it to 0 to disable H.264 encoding (and use Theora instead). By default HDX always prefer H.264. Set it to 1 to go back to default behavior.

ii. If you want to disable H264 on the VDA side instead, it is also possible by setting:

HKLMSoftware Wow6432NodeCitrixHdxRealTime

DWORD EnableDeepcompress_Server – set it to 0 to disable H.264 support.

Please note that when H.264 is disabled, the webcam resolution must be integral multiple of 16. So, 1920*1080 is not supported. User can use other resolution like 1280*720, so apply the defaultwdith and defaultheight regkeys described in 7.1

  • HDX RealTime Webcam Video Compression supports ICA double-hop for webcams.


7. Advanced Configuration

Caution! Refer to the Disclaimer at the end of this article before using Registry Editor.

There are settings that can be configured on the user device that can assist in troubleshooting and solving problems with specific webcams and networks. Generally, these settings must be adjusted as a last resort. Changing the settings too much can lead to severe video artifacts and video sluggishness.

7.1 Resolution

As of XenApp 7.18 and XenDesktop 7.17 (with Receiver for Windows 4.10 or higher), all supported resolutions by the webcam are presented to the hosted app trying to access it, so it can pick the desired resolution.

By default, Citrix Receiver for Windows 4.10 or older and non-Windows Receivers use CIF resolution (352 x 288) to stream webcam video to the XenApp/XenDesktop host.

A scaling function allows applications to request resolutions other than the default. The CIF frames are scaled appropriately on the VDA before delivering them to the application.

To manually adjust (and force) the webcam video resolution, create (on the Client) two DWORD values named DefaultWidth and DefaultHeight under HKEY_CURRENT_USERSoftwareCitrixHdxRealTime.

The resolution directly affects the bandwidth consumed and the overall quality of the video.

Some Webcams (specially integrated) might not support CIF, and Webcam detection might fail on an older VDA (like 7.15 LTSR).

Editing the Registry for a known supported resolution (like 640 x 480 or 1280 x 720) might fix the issue.

Note that the higher the resolution, the higher the bandwidth consumption between Workspace app and the VDA.

Try a lower known supported resolution (e.g. 480p) to avoid high network traffic.

You can find this by launching the Camera app in Windows 10 and clicking on Settings:

User-added image

Client-side registry:

User-added image


User-added image

7.2 Frame Rate

The preferred video frame rate can be adjusted by creating (on the Client) a DWORD (32-bit) value named FramesPerSecond under HKEY_CURRENT_USERSoftwareCitrixHdxRealTime. Because it is possible to input a value that the webcam does not support (e.g 31 FPS), the actual frame rate might be different as seen by the hosted application (e.g. 10 FPS). When this key is not present, a default value of 15 frames per second is selected. The actual frame rate used is dependent upon the Webcam.

For example, an old WebCam device might only support up to 10 fps in 1280*720 resolution for I420, NV12, YV12, YUY2 video format (the formats supported in H.264 encoding, plus RGB with Theora encoding). To confirm this, use a third-party tool (like DumpVCap or GraphStudioNext) to verify.

–DumpVcap output–
Major Type Sub Type Format Type FixedSamples Temporal Compression Sample Size Max Input Size Min Output Size Max Output Size Min-Max FPS
Video YUY2 VideoInfo Fixed NotTemporal 1843200 1280×720 1280×720 1280×720 5.00-10.00 {none}

Video YUY2 VideoInfo2 Fixed NotTemporal 1843200 1280×720 1280×720 1280×720 5.00-10.00 {none}

Video MJPG VideoInfo Fixed NotTemporal 2764800 1280×720 1280×720 1280×720 5.00-30.00 {none}

Video MJPG VideoInfo2 Fixed NotTemporal 2764800 1280×720 1280×720 1280×720 5.00-30.00 {none}


From the output, it is clear that at 1280*720 resolution, the WebCam device can support 5~10 fps for YUY2 video format and 5~30 fps for MJPG video format (but not supported in HDX). In this case, only up to 10FPS can be used by the hosted app.

Most modern webcams like the integrated ones in a Surface device (e.g. OV5693) support at least 640×480 (480p 4:3) or 640×360 (wide 360p 16:9) and 15-30 FPS (see SETTINGS screenshot above).

7.3 Bandwidth

The bandwidth usage can be tweaked by creating a DWORD (32-bit) value named TargetBitrate under HKEY_CURRENT_USERSoftwareCitrixHdxRealTime. Values are in bits per second, so if 300 kbps is desired, the value should be set to 300000. When this key is not present, the default value is 350000. During testing, somewhere between 250000 and 300000 was found to be the minimum values for the default CIF resolution or 480p that still produced acceptable video quality. If the resolution and frame rate are set to lower values then it might be possible to lower the bit rate and reduce bandwidth consumption. Lastly, setting the bit rate to zero has special meaning – zero indicates that the codec should operate in VBR mode. However, during production testing, the codec would generate excessive video artifacts so VBR mode is NOT recommended.

7.4 Encoders

Citrix Workspace app for Windows supports H.264 (Default) and Theora (legacy) encoders. If for whatever reason you want to disable H264 (not recommended), the following registry key on the client can be used:

HKEY_CURRENT_USERSoftwareCitrixHdxRealTime

DWORD EnableDeepcompress_Client – set it to 0 to disable H.264 encoding. By default HDX always prefer H.264 decoding. Set it to 1 to go back to default behavior.

If you want to disable this on the VDA side instead, it is also possible by setting:

HKLMSoftwareWow6432NodeCitrixHdxRealTime

DWORD EnableDeepcompress_Server – set it to 0 to disable H.264 support.


8. Troubleshooting

8.1. Device Manager on the Client would list the same webcam names as done by the Citrix Workspace app Desktop Viewer. Although keep in mind that there is no single designated place where they show inside Device Manager. This is device specific. Most common place is under Imaging Devices. Integrated webcams might show in other places.

8.2. Citrix Workspace app Desktop Viewer preferences should list all the available webcams on the client. If that drop down does not show webcams at all, that means the Client cannot access the local webcams.

In this scenario, redirection will not work. If you run into this problem, try launching apps like Skype for Business, Skype or GoToMeeting LOCALLY to confirm that webcam devices are not available on the endpoint either.

This can happen because of various reasons, most commonly device drivers not installed correctly because of which Windows cannot recognize webcams.

For HDX Realtime webcam video compression, the device drivers are not needed on the VDA, only on the Client.

For Generic USB redirection, drivers are needed at both the VDA and on the Client machine.

8.3. Make sure the following Computer policies “Windows media Redirection” and “Multimedia Conferencing” are Enabled in Studio.

By default, all multimedia policies set on the Controller are stored in these registries:

Computer policies:

HKEY_LOCAL_MACHINESoftwarePoliciesCitrixMultimediaPolicies

User policies:

HKEY_LOCAL_MACHINESoftwarePoliciesCitrix{User Session ID}UserMultimediaPolicies

To locate the current user session ID, issue the qwinsta command on the Windows command line.

Keep in mind that these two policies are Enabled by default, and policies that are enabled by default will not show under those regkeys (only policies that are explicitly configured will).

8.4. Once you plug a webcam in your session, or if the webcam was already plugged when the session started,

the following registry entries should be seen on the VDA:

User-added image

Information on the MediaPropertyData values can be found here.

8.5 If some apps on the VDA can display the webcam, but some other app or self-preview window shows a black or grey screen instead of the video feed, you might need to whitelist the application. This applies to Workstation VDAs only (Windows 10 / Windows 7).

Add a key with the name of your app executable (e.g. myapp.exe) under:

HKEY_LOCAL_MACHINESOFTWAREWOW6432NodeCitrixCtxHookAppInit_DllsCtxMFPlugin

and

HKEY_LOCAL_MACHINESOFTWARECitrixCtxHookAppInit_DllsCtxMFPlugin

DWORD “HookProcess” = 1


User-added image

Related:

Citrix VDI Desktop Viewer 'No Device' for USB

When using Citrix XenDesktop 7.5 for VDI and Windows7 physical machine and connect to VDI Win7 PC the user attempts to use the Desktop Viewer bar and select ‘Devices’. This says ‘No Devices’ and it doesn’t see any USB devices.

A thin client which the same Citrix Policies apply to and this works with USB, users can’t currently find what they are missing from their settings. The device being used is Kingston Data Traveler 2.0.

Related:

Headsets not working within published desktop

SOLUTION:

1. Ensure the following check boxes are checked:

“When a session starts connect the device automatically” and “when a new device is connected while a session is running connect the device automatically”

Unplug and Replug the headset after checking the boxes and test.

2. Switch the virtual channels to generic from optimized and test the headset.

NOTE:

REFER: https://docs.citrix.com/en-us/citrix-virtual-apps-desktops/devices.html

In general, you get better performance for USB devices in Optimized mode than in Generic mode. However, there are cases where a USB device doesn’t have full functionality in Optimized mode. It might be necessary to switch to Generic mode to gain full access to its features.

3. Confirm if unplugging and plugging the headset was switching the virtual channel to Optimized from Generic

– If yes, then the device is by default getting redirected as optimized

Refer : https://support.citrix.com/article/CTX206109

Create the following registry :

HKEY_LOCAL_MACHINESOFTWARECitrixICA ClientGenericUSBDevices

Name: AutoRedirectAudio

Type: DWORD

Data: 00000001

– Restart the client machine after creating the registry key

– Check the Citrix studio and create the following policy :

Value : Mode000001 VID : XXX PID: XXX Class 01

NOTE : Check receiver version and install recent / latest receiver / workspace version and test the issue.

Related:

Using Application & Device Control on an unmanaged SEP 14 client

I need a solution

Hi,

I want to know the best way forward where we have a number of Windows 10 clients which will either never connect to a network or may rarely do so.  I am thinking of making them unmanaged clients in this case,which will be no plroblem from an update point of view as they will be able to update using the intelligent updater files from Symantec, however we also need to manage the USB devices so that only  certain ones can be utilised.  The list of approved USB drives will be subject to regular changes and we will need to have the ability to add / remove them in the field on the unmanaged clients.

From what I have read, this sounds as though this will need to be done by creating the appropriate policy on a computer with the SEP Manager inistalled,and then the policy shipped out to the client and imported, but this sounds potentially cumbersome so I was wondering if there is another way of doing this on the unmanaged client directly using the latest version of SEP.

Please can someone advise me the best way forward,

Thanks

Chris

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