How to choose camera device used by cam_align?

cmorley wrote:

yes qtvcp in 2.8 does not support the -o option it seems
I can add it but you'd have to wait for next release or modify the code yourself.

I'ld like to try. You've got a diff for me?

Ok here you go:
Let me know how it goes - I'll push to 2.8 if all is good.


Chris

patching cam_align_handler.py and camview_widget.py suceeded

But there is no such file qtvcp.py on my 2.8.1 installation.

There is such a file somewhere.
Are you using a compiled version or an installed version?

I Installed via iso image and updated with apt-get

"locate qtvcp.py" gives nothing neither does "locate qtvcp.pyc"

try locate qtvcp

the .py is removed and it's probably in bin/

Sorry I don't have an installed version handy to check

I could locate and patch the file as /usr/bin/qtvcp
The -o option now is accepted.

But I don't get a video display in the axis tab:

# Embed tabs
EMBED_TAB_NAME= fideo
# -Wn wait for 'name' -c give 'name'
EMBED_TAB_COMMAND= halcmd loadusr -Wn qtvcp_embed qtvcp -d -o 0 -c qtvcp_embed -x {XID} cam_align

The "fideo" tab says: "No image"

But with standalone "mpv av://v4l2:/dev/video0" the stream is displayed.

qtvcp uses opencv for camera interfacing.
it's possible your camera is not compatible with the default settings.
specifically it assumes the camera gives BGR and converts to RGB
(cv2.COLOR_BGR2RGB)

I had assumed you did get a picture but needed a different camera selection.

Can you try a different camera to see if it works?
also checking in the terminal may give some clue (but you might have to look carefully)