Picture, sound and input
Judge picture problems from a visible browser tab: a hidden tab throttles presentation and skews every client-side number.
Black screen, session says running
Section titled “Black screen, session says running”Check the session detail in Admin ▸ Sessions:
| Check | Fix |
|---|---|
| Resolved codec | The browser may not decode it (stale decode measurement). Log out and back in on that device. |
| Exit reason | The app exited. See Launching a game. |
| Host frame rate is 0 | Nothing is being produced; the problem is on the host. |
The picture is corrupt or full of artefacts
Section titled “The picture is corrupt or full of artefacts”| Cause | Fix |
|---|---|
| Packet loss (rising loss series in session detail) | A network problem, not the encoder. |
| NVIDIA Vulkan AV1 corruption | Use driver 610 or newer. Where a known codec restriction applies, use HEVC or H.264 if the profile and client support them. See NVIDIA compatibility. |
| Vulkan host with HEVC, one frame in four black or torn | Undo any hand-set encode ring depth. QUASAR_VULKAN_HEVC=1 sets it correctly. |
No sound
Section titled “No sound”- Check the session detail for degraded audio and its reason.
- Check the audio sidecar image comes from the same release as the agent image.
- Sound in some apps only: the app chose another output device in its own settings.
To fail the session instead of running silently:
QUASAR_AUDIO_REQUIRED=1The microphone button is missing or does nothing
Section titled “The microphone button is missing or does nothing”| Symptom | Fix |
|---|---|
| Missing | Turn it on in Admin ▸ Settings. |
| Greyed out | Release input capture first. |
| Does nothing | Allow the browser permission, and use HTTPS. |
A live microphone always shows an indicator.
The mouse does not move, or moves wrongly
Section titled “The mouse does not move, or moves wrongly”- Capture input (the first item in the drawer).
- Check the host’s
uinputandinput_probereadiness checks. Rootless: install the device rules. See Readiness checks. - Pointer offset in a desktop session: update Quasar.
Escape leaves fullscreen instead of reaching the game
Section titled “Escape leaves fullscreen instead of reaching the game”Escape needs a Chromium browser, fullscreen and HTTPS. The drawer says which is missing; usually it’s HTTPS.
Keyboard input goes to the browser
Section titled “Keyboard input goes to the browser”Capture input. If keys still don’t arrive, check /dev/uinput as for the mouse.
Controllers not detected
Section titled “Controllers not detected”- Press a button: browsers hide a gamepad until it sends input.
- Use HTTPS.
- Check the
uinputandinput_probereadiness checks. - Rootless Docker, pad listed but ignored by the game: update the app’s image.
Controller buttons are in the wrong places
Section titled “Controller buttons are in the wrong places”Games see an Xbox 360 controller. Some pads (for example 8BitDo over Bluetooth) aren’t reported in the standard layout, and the Controller & input pane says so. Switch the pad to XInput mode, or connect it by cable or USB receiver.
X and Y are swapped on a gamepad page inside the session
Section titled “X and Y are swapped on a gamepad page inside the session”A gamepad tester or web game opened in a browser inside the streamed desktop shows X and Y swapped (seen in Firefox). Games and Steam read the pad correctly. Only web pages in the session that use the browser’s Gamepad API are affected. The virtual pad is not backed by the Xbox kernel driver, so Firefox reads X and Y differently. This is a known limit; there is nothing to change.
Touch input on a tablet
Section titled “Touch input on a tablet”Touch is forwarded. Open the session drawer with the on-screen button. Most games still need a controller.