FAQ

• Stuttering if another process uses the GPU
• Websocket connections are stuttering
• Stuttering when connected over Wifi
• The browser preview seems to have a low frame-rate
• Preview timed out
• Library not found
• AirPointr Raspberry does not start, outputs error messages

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### Stuttering if another process uses the GPU

AirPointr Raspberry uses the GPU for preprocessing. Thus if another process such as an OpenGL application uses the GPU, camera frames will be dropped. Please make sure that no other process uses 3D acceleration while AirPointr is running.

### Websocket connections are stuttering

The preview uses a websocket connection for the gesture input. Please note that some Operating Systems and browsers optimize for bandwidth. Therefore you will experience a stuttering connection. Please see the list of working combinations.

### Stuttering when connected over Wifi

Network aspects, as connection type (Wireless/Cable) or network traffic, can also have an impact on the performance. Please check your network latency "ping".

### The browser preview seems to have a low frame-rate

Some browsers have issues with their websocket implementation on certain OS (namely some Firefox versions on Windows). That will cause WebSocket messages to be buffered and to arrive in bursts (framerate ist still the full 30 Hz but several frames arrive together after a pause of several milliseconds). Furthermore WiFi tends to introduce delays and similar buffering artifacts.

### Preview timed out

The preview says it has timed out directly after starting AirPointr although the timeout is nonzero. For privacy considerations the camera preview feature of AirPointr gets disabled based on system uptime. Also the timeout cannot be reset or changed from within the browser interface.

These features are intended to assure that even if the webconfig of AirPointr is reachable (e.g. private LAN) the camera cannot be re-activated without either physical access to the RasPi (power cycling) or console access with sufficient privileges (change your root password...)

### Library not found

Library not found ("error while loading shared libraries: lib...: cannot open shared object file: No such file or directory")

Well... uhm... that shouldn't happen. Usually this only happens if you try to run the binary airpointr executable directly (airpointr.bin) instead of the loader script (which sets library search paths accordingly).

If you still run into this kind of an error, please do not hesitate to send email to our support stating the exact error and your specific linux distribution.

### AirPointr Raspberry does not start, outputs error messages

Again - that should not happen but there is one well kown case where this might happen: If your camera is in use by another application AirPointr Raspberry will not be able to initialize it. In that case the program will terminate with an error like

[critical] camera thread returned nonzero (70) - terminating

The lines above that message will generally give you more details on the cause. If you get something like mmal_vc_component_enable: failed to enable component: ENOSPC you may want to check that no other program is currently using your camera. Furthermore make sure you have enabled the camera using raspi-config.