Image tearing occuring in client

[Gabriel Tumang]

I am running a setup based on this tutorial on a Raspberry PI 3+ on Raspberry PI OS Buster, but instead of a tigervnc server, i am using x11vnc.

The application works as supposed (reverse proxy server & websockify service), however the embedded noVNC client has an image tearing problem (view annexed files). When connecting using RealVNC Viewer with the same server configs, the tearing doesn't occur. I tried adjusting quality and compression values on the js file, but to no avail. I am connecting to the raspberry pi server on my LAN, and the latency values seem low enough to not be a problem (3 ms). I also tried messing with the x11vnc server refresh rate configuration, and it seems to help a little, but not enough. 

I appreciate any suggestion. Thanks in advance!

[Pierre Ossman]

On 17/03/2025 20:51, Gabriel Tumang wrote:
> I am running a setup based on this tutorial

> <https://datawookie.dev/blog/2021/08/websockify-novnc-behind-an-nginx-proxy/> on

RealVNC can be a bit difficult to compare with, given its proprietary
nature. Could you test with TigerVNC's viewer and see if shows the same
issue?

Regards,
--
Pierre Ossman Software Development
Cendio AB http://cendio.com
Teknikringen 8 http://twitter.com/ThinLinc
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Phone: +46-13-214600

A: Because it messes up the order in which people normally read text.
Q: Why is top-posting such a bad thing?

[Gabriel Tumang]

Hello Pierre,

I just tested it with TigerVNC, and it also does have the tearing problem.However, changing the encoding from tight to raw appears to have solved the issue! Excuse my ignorance, but could i do the same with noVNC's configuration?

Thank you for your suggestion, 

Best regards

[Gabriel Tumang]

I have solved the issue. Apparently the culprit was Thight encoding. Testing with the other types on TigerVNC viewer yielded unproblematic
 results. So I edited out the line of code on rfb.js that pushed tight encoding into the encoding type list, and it worked on my noVNC client as well.

[Pierre Ossman]

On 3/18/25 12:14, Gabriel Tumang wrote:
> Hello Pierre,
>
> I just tested it with TigerVNC, and it also does have the tearing
> problem.However, changing the encoding from tight to raw appears to have
> solved the issue! Excuse my ignorance, but could i do the same with noVNC's
> configuration?
>

I'm afraid we don't have such a setting. It's generally not something
end users should need to deal with.

The fact that it is seen with two different clients suggests the issue
is with x11vnc, not with noVNC or TigerVNC.

I would suggest reporting the issue to x11vnc and let them have a look.

Regards,
--
Pierre Ossman Software Development

Cendio AB https://cendio.com
Teknikringen 8 https://twitter.com/ThinLinc
583 30 Linköping https://facebook.com/ThinLinc