Enforce Encoding Method for a VNC Session

[Andrew]

I'm using TurboVNC 2.2.5 and am trying to limit the total bandwidth all VNC sessions consume in my environment. Analysis has shown the "Tight + Medium-Quality JPEG" Encoding method is much easier on the network without sacrificing quality. 

What I'd like to do is enforce this encoding method and prevent users from changing it. I've tried the "-alrqual" parameter on the vncserver which works, but a user is still able to change the encoding method by bringing up the options menu in their viewer. 

Is this "lock down" currently possible? I appreciate any feedback. 

[DRC]

-alrqual only changes the quality of images sent when an automatic
lossless refresh occurs.  It doesn't change the base quality of images
that the server sends.

In the RFB protocol, the encoding type and (in the case of Tight
encoding) the compression level, quality, and subencoding types are
configurable using client-to-server messages, so the only way to forbid
clients from changing those parameters is to tell the server to ignore
those messages.  There's no way to do that without modifying the
TurboVNC Server source code.  I'm attaching a patch to demonstrate how
to do that.  I don't have any interest in making such functionality an
official feature, but it should be relatively straightforward to
maintain a GitHub fork with this patch.

[Andrew]

Thank you very much for your explanation and patch . 

I appreciate your time.