How to switch between cameras
There are three methods for selecting between the cameras. These are “Keep active”, “Fast” and “Robust”, in the preferred order.
Keep Active: Tries to start two camera streams and keep both active. Switching the active video stream is handled inside LitePlacer software. This consumes more USB bandwidth, but is the fastest method, if your system supports it.
Fast: Asks the OS to stop the camera video feed, but keeps them on the USB bus. Activate this method by unselecting “Robust” checkbox.
Robust: Asks the OS to disconnect the inactive camera from the bus and reconnect the active one.
Please note, that Windows doesn’t always honor these requests, and LitePlacer software doesn’t go deep into the USB management system. (Therefore, “asks”, not “forces”.)
Troubleshooting tips:
Some machines have had issues on selecting between the cameras. Things that have helped:
- Connecting cameras directly to a computer (not through a hub)
- Connecting cameras to different USB ports, so that they are using different USB controller chip inside the machine
- A tip from a customer: “Solved it; went into device manager, selected one of the cameras and clicked “Update driver” then selected to browse manually for a driver and continued to select from a list of devices, selected “Imaging devices” -> Microsoft -> USB Video camera.”
- The OpenPnP folks have encountered similar issues with USB and cameras as some LitePlacer users. Jason von Nieda, the guy behind OpenPnP, has written a good page about the issue: https://github.com/openpnp/openpnp/wiki/USB-Camera-Troubleshooting-FAQ.
- Also, this thread has good hints and a link to a tool that might help in diagnostics:
https://groups.google.com/forum/#!topic/openpnp/17d9WNn3DhY.