By Fredrik Brattstig @virtualbrat
Citrix recently shared an Early Access Release of the Citrix Workspace App for Linux 2408 (CWAL2408) with IGEL. One of the biggest features that are added, that I have been waiting for a very long time, is the H.265 enablement for Hardware Acceleration of the session delivery.
Let’s back up the bus a bit. IGEL has been very successful delivering hardware accelerated graphics with Citrix, although, it has been limited to using H.264 video compression standard. Finally, we now see the birth of H.265/HEVC in the Citrix Workspace App for Linux. Why has this been a long-awaited improvement?
Technically H.264 and H.265 is pretty comparable in terms of how the codecs operate. but there are big differences.
H.265 enables encoding/decoding 8192×4320 pixels, which includes 8K UHD resolutions, and it offers 25% to 50% better data compression rate compared to H.264, which is very important to deliver the same session video quality in more limited bandwidth scenarios. The technical preview of CWAL2408 is currently limited to 4096×4096 rendering surface.
Read the release notes of this feature here: https://docs.citrix.com/en-us/citrix-workspace-app-for-linux/ear.html#support-for-h264-and-h265-hardware-decoding-technical-preview
One more important thing to mention about the Hardware acceleration in CWAL2408 is that Citrix is now taking care of the hardware acceleration in the CWAL using OpenGL as rendering engine. Previously Citrix enabled 3rd party partners to take care about the hardware acceleration, which IGEL has been doing very successfully over the years. This all simplifies the process for IGEL of implementing the CWAL including Hardware Acceleration, and is just controlled by a simple setting switch.
As IGEL has now enabled the use of the CWAL2408 in non-production environments and will soon offer the final General Availability version, as soon as it is released by Citrix. If you want to start testing the CWAL2408EAR with H.265 support, reach out to your favourite IGEL contact to get it sorted, or wait for a few weeks for the General Availability.
IF you will be testing with the 2408EAR version, there are some hacks needed to be done to enable the Hardware Acceleration and H.265. Open a Terminal, login as ‘root’ and type:
vi /userhome/.ICAClient/wfclient.ini
Find the section [WFClient], and press the "Insert"" button on your keyboard to enable editing
Add a new line in the [WFClient] section and add the following two lines:
OpenGLEnabled=True
H265Enabled=True
Now press "ESC" key on your keyboard and then type :wq to write the file changes, and quit vi.
After this is done, you can launch the CWAL2408EAR again, and connect to your GPU enabled sessions, H.265 should now be enabled within session.
Putting the compression to the test. Does H.265 really differ from H.264?
Citrix session is 4K (3840x2160pixels), Citrix VDA and IGEL OS client is on the same physical network. Citrix VDA is a Windows 11 VM running in XenServer 8. IGEL OS is a physical old IGEL UD7 running IGEL OS 12 with the CWA 2408EAR.
Using WanEm, I tested to limit the bandwidth between the Citrix VDA and the IGEL OS Client. On H.265, with as low as 3.500Kbps the session was maintaining >25 Frames Per Second (FPS) stable for the complete Reflections demo. Changing the codec to H.264, 3.920Kbps was needed to maintain >25FPS to give an acceptable user experience of the Reflections demo.
In this, not-very-scientific test, H.265 decreased the bandwidth needed by about 10.71%, which is a clear enhancement in favor of H.265. I’ll check if I can do some more scientific testing in a later blog when the final of CWAL2408release is here!
I provided a short video showing the H.265 in play. I’m connecting to a Citrix Desktop running Windows 11, and has an NVIDIA partitioned RTX6000. The GPU supports RTX – which means hardware-enabled real-time ray tracing. RTX comes greatly into play in the demo, as the demo is not a video playback, it is real-time rendered! Enjoy!
PS. Just before I published this post, IGEL got new binaries from Citrix promising even better performance, and IGEL development committed to creating Profile configuration items to enable hardware Acceleration and H.265. I see a follow-up blog post coming 🙂
VirtualBrat 