switch camera

[quozl]

Some systems have more than one camera, or an external camera such as a microscope or webcam can be connected to USB.

At the moment, Record cannot handle a second camera unless it is present before the base camera is probed. Timing of probing of base camera varies by hardware platform and how the kernel is configured. Cameras can be identified by /dev/v4l links, or through GStreamer.

For example, connecting a microscope yields:

• /dev/video1 character device,
• /dev/v4l/by-id/usb-Vimicro_Corp._Venus_USB2.0_Camera-video-index0 symbolic link to /dev/video1
• /dev/v4l/by-path/platform-d420a000.camera-video-index0 symbolic link to /dev/video1

Suggestions:

• offer a toolbar icon with a list of cameras to use,
• if camera is changed, stop the stream, change the device, restart the stream.

[godiard]

The initial work has started in multiple_cameras branch. When finished will be merged.