Problem setting bitrate through web interface

[lastbestmatt]

While using rpos, I noticed that when setting video_bitrate through the web interface, the value is not preserved. The value always reads '0' in the v4l2ctl.json settings file. I tracked this down to what I think is a RegExp bug in v4l2ctl.ts

In the ReadControls() function, we take the control name and append the variable regexPart to create a RegExp that is matched against the output of v4l2-ctl -l command.

The problem shows when two different controls start the same way: in this case video_bitrate_mode and video_bitrate. The regex will match video_bitrate_mode for both controls. So, when you attempt to set video_bitrate, it takes affect and even gets written to file correctly. But anytime the file is read, the value of video_bitrate_mode will be captured for both controls.

To fix, you could change

var regexPart = ".*value=([0-9]*)";

to

var regexPart = "\\s.*value=([0-9]*)";

This will require whitespace after the control name, which will limit the RegExp to only match the correct control.

[RogerHardiman]

Thanks for the bug report.
I had seen this problem but never had the time to investigate so thank you for the fix.

Will we always have a whitespace after the name in v4l2-ctl?
Is that part of the formatting?

[lastbestmatt]

It's a good question, I'm not sure. I also considered \b for a word break, which would catch both a whitespace or a colon. However, this wouldn't allow for names with a hyphen (-) in them if those exist (it would allow underscores).

Just remember to escape the slash in the string, or you'll really confuse yourself.

[RogerHardiman]

I am back in the office now and checked my RPi.
The original regex is fine.
I have a fork of rpos (with extra things like PTZ support and Aux/Relay support) and will add it into my fork too.

[lastbestmatt]

For the record, we should note that the sense of auto_exposure is backwards in these settings. A value of 0, or unchecked, means auto exposure is on. A value of 1 or checked means manual exposure. Not sure the easiest way to note this in the interface, but I suppose you could change it to a menu/dropdown type where "on" = 0 and "off" = 1.

[RogerHardiman]

This bug has been fixed in RPOS now. (I've pulled in the Pull Request from my fork).
Thanks again for the bug report