[winswitch] issue with forwarding x to a lower res monitor from a virtual Xvfb

Zenny garbytrash at gmail.com
Sun Nov 15 14:15:16 GMT 2015


Please find some more updates:

§1 If I use Xdummy with xpra (as described in the wiki) and try to
capture with ffmpeg the virtual console at 4k while displaying the
remote in 1080p, it categorically reports as of below and fails to
capture:

[x11grab @ 0x2b2dc00] Capture area 3840x2160 at position 0.0 outside
the screen size 1920x1080
:10: Invalid argument

§2 If I use Xvfb directly with a single application (say xterm), and
run 'xpra start --use-display :10', it allows to screencapture, but
the capture of the window is dead black. (see attachment)

§3. As in §2 above, if I start a DE like (LXDE or i3), I get the
xrandr errors and the remote screen freezes.

Thanks!

On 11/15/15, Zenny <garbytrash at gmail.com> wrote:
> On 11/15/15, Antoine Martin <antoine at nagafix.co.uk> wrote:
>> I have tested here with Xdummy and that worked fine.
>
> Can you share your Xdummy command if different from the one in the wiki?
>
>
>>> I checked Xdummy related to Ubuntu instruction at
>>> https://www.xpra.org/trac/wiki/Xdummy, but to no avail.
>> Are you using Xvfb or Xdummy? What distribution and version?
>>> Any hints would be highly appreciated. Thanks!
>> You may also be interested in the following 0.16 features:
>> * ability to NOT change the virtual display to match the client's
>> resolution using:
>> XPRA_RANDR=0 xpra start ...
>> See:
>> http://xpra.org/trac/changeset/11229
>> Shadow mode is A LOT less efficient than the regular "start" mode.
>> * desktop scaling, which allows you to upscale or downscale the server
>> resolution when displayed on the client:
>> http://xpra.org/trac/ticket/976
>> So you could render at 4k and display at 2k for example (though the main
>> purpose of this ticket is to do the opposite to save bandwidth).
>> * "sync-xvfb" fix for screen capture tools:
>> http://xpra.org/trac/ticket/988
>>
>> Cheers
>> Antoine
>>
>>>
>>> Cheers,
>>> /z
>>> _______________________________________________
>>> shifter-users mailing list
>>> shifter-users at lists.devloop.org.uk
>>> http://lists.devloop.org.uk/mailman/listinfo/shifter-users
>>
>> _______________________________________________
>> shifter-users mailing list
>> shifter-users at lists.devloop.org.uk
>> http://lists.devloop.org.uk/mailman/listinfo/shifter-users
>>
>



More information about the shifter-users mailing list