vGPU w/K1 and vDGA w/K5000 are both blurred w/HTML5 Blast, fine with PCoIP in Horizon 7

Has anyone here come across an issue with Horizon 7 where use of the BLAST protocol results in a blurred screen (colors appear to be misaligned with noticeable blue and red “drop shadow” effects? I’m seeing the same issue with K1 vGPU (all profiles) as well as a separate system doing vDGA with a dedicated Quadro K5000. Both are ESXi 6.0U2 hosts. The problem ocurres in all of the 361 and 362 branch drivers I’ve tried. It shows up when I try to use the BLAST protocol, but everything works fine when using PCoIP. Only appears to happen with VMs that have assigned Nvidia GPUs. vSGA-based machines show no issues.

Hoepfully someone else has seen this before and can point me in the right direction.

Can you check my h.264 blog stream ? Anything look familiar… Artefacts quite distinctive…

Some further testing has continued to narrow the problem and I now believe it to be an issue with the Horizon 4.0.1 client for Windows. I was able to borrow a Mac and do some additional testing and the end result was that the Horizon client on the Mac worked properly regardless of the protocol being used. I need to do some additional client side testing to see if I can further isolate the issue, but at this time, it seems to be tied to BLAST with the windows client. I’ll have to try disabling h.264 to see if it might be something related to client side decoding being handled differently between platforms.

Regarding the mention of h.264 artifact issues pertaining to the encoding, it seems possible but in such a case, I’m surprised VMware would even release it with such a glaring user experience issue present.

You described "drop shadow" problem that leads to 4:2:0 H.264 encoding artifact (demonstration image is attached in blog). If your problems looks different you should attach some image.

It is also possible that the Mac client is not using H.264 in this scenario. You will have to check the Blast logs to be sure. Note that H.264 inherently creates display artifacts due to its use of a YUV 4:2:0 color space conversion that discards 75% of the chroma information from the pixels. (see: This is why modern remote display protocols use multiple codecs to encode computer displays and use H.264 only where it is appropriate rather than for all content (see: