If I am understanding correctly, it seems that you are trying to run jevois-daemon twice?
- when you run in desktop mode, you run jevois-daemon compiled for host and then usually use a standard webcam. jevois-daemon implements the various machine vision algorithms. When you run in desktop mode, those run on your desktop.
- now if you want the JeVois camera to do the work, you just plug it in, and jevois-daemon will start on it as soon as it boots. So you should not have to run jevois-daemon again on your host. You would just run guvcview or similar video viewer.
The JeVois camera is very picky and will reject attempts to grab video in a format that is not an exact match for those listed in the videomappings.cfg on its SD card. This is by design, so that, if you select an incorrect mode, you do not end up with the camera using a near match and then you think that you are running some algo while actually it is running another one. This would explain why the jevois-daemon you run on your host is not able to grab frames, maybe it is requesting a video mode from the JeVois camera which the camera does not provide as a valid output mode.
So if you indeed do want to chain two jevois-daemon, one running on the camera and then one running on host, the input (camera) mode selected for the one running on the desktop must be an exact match for a valid output (USB) mode of the one running on the camera.
With the default videomappings.txt, the camera will support 320x240@60 YUYV input from sensor to 320x240@60 YUYV output to USB and this will use the SaveVideo module. So if you run, for example, 640x300@60 YUYV (DemoSaliency) on your host, that would request 320x240@60 YUYV from the camera, and hence the SaveVideo module will be selected on the camera.
To try that pipeline, first run jevois-daemon on your host (with your other webcam) and type
then note the mapping number for DemoSaliency at 640x300@60 YUYV USB output.
Now connect your JeVois camera (if you do not disable your other one, JeVois will show up as /dev/video1, that is no problem), and, on your host, try
jevois-daemon --cameradev=/dev/video1 --videomapping=XX
where XX is the number you noted from listmappings. This is how you would chain two jevois-daemon processes, one on the camera and then another on the host. In summary, for this example:
jevois camera: grabs 320x240@60 YUYV and outputs 320x240@60 YUYV to USB (SaveVideo module runs on JeVois camera)
desktop: grabs 320x240@60 YUYV from your JeVois camera over USB, and outputs 640x300@60 YUYV which goes to a display window (DemoSaliency module runs on your desktop)