auto brightness bypass whilst using Motion

Question

Can I change the metering mode, exposure and ISO of my Raspberry pi noir camera whilst using the popular software Motion to detect, well, motion.

I don't seem to be able to lighten the image whatever i change in the motion.conf file, so wondered if i could bypass the auto exposure mode on the camera board whilst still using motion.

Their's a bright street light that's making the overall image too dark, and i don't mind that part being over exposed, as long as i can see some of the dark bits in the cornets of the picture

Thanks in advance,

Reggie.

Answer 1

Would you believe it, I actually had some success last night in this area!

I changed the ; mmalcam_control_params value to mmalcam_control_params -ex sports -ev 25 --shutter 256000 the auto_brightness on the brightness 255 the contrast 1 the saturation 5 and the hue 0.

I also found that jpgs performed better than movies so set output_pictures on and picture_type jpeg.

I found whatever I did, nothing changed. I tried so many combinations of brightness/contrast etc, I gave up, until last night.

They changed my street lighting to LED, which made it much worse. I had to act last night or get a load of black jpgs; so I had another play and bingo.

The biggest change came with playing around with mmalcam_control_params -ex sports -ev 25 --shutter 256000, but I'm not sure if the combination allowed this to have an effect.

I also found setting the motion.conf file to user and group motion allowed me to play with the settings using motions web interface, which is useful.

You have to restart motion each time you make a change, for the change to take effect, just a point to remember.

Good luck,

Reggie.

p.s I also wrote a script to automatically change the motion.conf from "day settings" to "night settings" and back again, if your interested.

Answer 2

I have found more success controlling the exposure using v4l2-ctl than by modifying the motion.conf file. If you wanted to use cron, then note that the v4l2-ctl method doesn't require restarting motion, and happens immediately at the camera. I change the exposure setting via a SSH on my phone and see the change from the stream straight away.

What would be even better would be to have motion run the commands for changing exposure based on overall brightness figures, rather than cron based on time.

Good luck with it.