looking-glass/doc/faq.rst

Frequently Asked Questions
##########################

General
-------

.. _how_does_looking_glass_work:

How does Looking Glass work?
~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Please see the following video that covers this:

https://www.youtube.com/watch?v=U44lihtNVVM

.. _can_i_feed_the_vm_directly_into_obs:

Can I feed the VM directly into OBS?
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Looking Glass now features a functional :doc:`OBS plugin <obs>`, which acts as
another Looking Glass client, but instead gives the captured frames to OBS.

.. _why_is_my_ups_so_low:

Why is my UPS (Updates Per Second) so low?
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

There are several reasons why this can happen, the most common are your
capture resolution, or refresh rate. The windows capture methods currently
struggle to capture high resolutions under certain circumstances.

Another cause can be how the game or application you are running is
configured. Because of the way windows integrate with the WDM (Windows
Desktop Manager), running applications in "Full Screen" mode may—in some
cases—cause a large performance penalty. Try switching to windowed
full-screen mode, the difference in performance can be like night and
day.

Some titles do some strange things at early initialization that cause
capture performance issues. One such title is the Unigine Valley
benchmark where the capture rate is limited to 1/2 the actual rate. For
an unknown reason to both myself and the Unigine developers a simple
task switch (alt+tab) in and out resolves the issue. This is not a
Looking Glass bug.

.. _is_my_gpu_supported:

Is my GPU supported?
~~~~~~~~~~~~~~~~~~~~

Your guest GPU almost certainly supports DXGI. Use DxDiag to confirm
that you have support for WDDM 1.2 or greater.

The server-side (guest) probing error "Capture is not possible,
unsupported device or driver" indicates NVidia duplication has failed,
not that DXGI has failed. You can fix the error by specifying
``-c DXGI``

.. _why_do_i_need_spice_if_i_dont_want_a_spice_display_device:

Why do I need Spice if I don't want a Spice display device?
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

You don't need Display Spice enabled. Looking Glass has a Spice client
built in to provide some conveniences, but you can disable it with the
"-s" argument.

Note that without Spice, you will not be sending mouse/keyboard events
to the guest, nor will you get clipboard synchronization support.

.. _where_is_the_host_application_for_linux:

Where is the host application for Linux?
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The "Windows host application" is actually the display server, which
runs in the guest VM. The only thing that needs to run in your Linux
host OS is the \`looking-glass-client\` application.

Mouse
-----

.. _the_mouse_is_jumpy_slow_laggy_when_using_spice:

The mouse is jumpy, slow, laggy when using SPICE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Please be sure to install the SPICE guest tools from
https://www.spice-space.org/download.html#windows-binaries.

.. _how_to_enable_clipboard_synchronization_via_spice:

How to enable clipboard synchronization via SPICE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Install the SPICE guest tools from
https://www.spice-space.org/download.html#windows-binaries.

Choose only one of the settings below (the one that applies to your
configuration):

-  QEMU

.. code:: bash

   -device virtio-serial-pci \
   -chardev spicevmc,id=vdagent,name=vdagent \
   -device virtserialport,chardev=vdagent,name=com.redhat.spice.0

-  libvirt

   -  Edit the VM using virsh ``sudo virsh edit VIRTUAL_MACHINE_NAME``
   -  Paste the code from below right above (note the closing tag)

.. code:: xml

     <!-- No need to add VirtIO Serial device, it will be added automatically -->
     <channel type="spicevmc">
       <target type="virtio" name="com.redhat.spice.0"/>
       <address type="virtio-serial" controller="0" bus="0" port="1"/>
     </channel>

.. _the_mouse_doesnt_stay_aligned_with_the_host.:

The mouse doesn't stay aligned with the host.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

This is intentional. The host's mouse no longer interacts with your operating
system, and is completely captured by Looking Glass.

.. _the_cursor_position_doesnt_update_until_i_click:

The cursor position doesn't update until I click
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Make sure you have removed the Virtual Tablet Device from the Virtual
Machine. Due to the design of windows absolute pointing devices break
applications/games that require cursor capture and as such Looking Glass
does not support them.

Audio
-----

Looking Glass does not support audio routing. The preferred
solution is to pass through QEMU's audio to your host's audio system.

Another popular solution is to use
`Scream <https://github.com/duncanthrax/scream>`_, a virtual sound card which
pipes audio through the network. A guide for setting up scream is available on
the wiki: https://looking-glass.io/wiki/Using_Scream_over_LAN




Windows
-------

.. _nvfbc_nvidia_capture_api_doesnt_work:

NvFBC (NVIDIA Capture API) doesn't work
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

NvFBC is only supported on professional-grade GPUs, and will not function on
consumer-grade cards like those from the GeForce series.

.. _the_screen_stops_updating_when_left_idle_for_a_time:

The screen stops updating when left idle for a time
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Windows is likely turning off the display to save power, you can prevent
this by adjusting the \`Power Options\` in the control panel.