Hi Miroslav,
It's likely that TigerVNC is using JPEG to encode the updates it send to
Guacamole, hence the artifacts / poor quality. This will also lead to
performance degradation, as the JPEG artifacts will decrease the efficiency
of the PNG compression used by Guacamole for most images.
You can change this behavior by explicitly setting the "encodings"
parameter of the VNC connection(s) to a space-delimited list of encodings
which does NOT include the "tight" encoding (the VNC encoding that uses
JPEG). A known-good value is:
zrle ultra copyrect hextile zlib corre rre raw
If you are using the database auth, I have a SQL script which updates all
VNC connections, setting the "encodings" parameter to the above value:
https://gist.github.com/mike-jumper/35987e86c64cac389e8b
This shouldn't be a problem going forward, as the default for "encodings"
has been changed to exclude the "tight" encoding. If you're OK with
building from git, that should solve things as well:
https://github.com/apache/incubator-guacamole-server
If you follow the current version of the manual for building from git,
beware that the manual still refers to the version of Guacamole prior to
its migration to the Apache Incubator, so the names and URLs of the git
repositories will be incorrect. The new repositories are all of the form "
https://github.com/apache/incubator-guacamole-*";.
Thanks,
- Mike
On Mon, May 23, 2016 at 12:43 PM, Miroslav Vadkerti <[email protected]>
wrote:
> Hi,
>
> I am experiencing bad image quality when connecting to my TigerVNC server
> via guacamole. With the TigerVNC viewer the image is sharp. Any idea what
> could be wrong? Could be that the guacamole vnc client is using wrong
> encoding or jpeg transport?
>
> Thanks,
> /M
>
