Blocky image artifacts corrupting snapshots

Question

Every image collected is spoiled by a number of blocky image artifacts that appear to be where regions of the image have been swapped or currupted.
I am using a RaspberryPi B+ with the Raspicam and three USB Logitech 120's
The Raspicam works fine, but all of the USB cams suffer from this issue. I have tried changing the snapshot interval so that they rarely coincide, but this makes no difference.

I invoke motion with LD_PRELOAD=/usr/lib/uv4l/uv4lext/armv6l/libuv4lext.so motion -c motion.conf 

 [[%ATTACHURL%/motion.conf][motion.conf]]
[[%ATTACHURL%/PiCam.conf][PiCam.conf]]
[[%ATTACHURL%/USB1.conf][USB1.conf]]

Environment

Motion version:	3.2.12
ffmpeg version:
Libraries:	uv4l
Server OS:	Rasbian

-- SimonC - 20 Jan 2015

Answer

Hi Simon. You seem to be someone who knows what you're on about so I apologize if these questions are a bit basic. No disrespect intended.

Does the problem happen when you only have one USB cam connected? Obviously there's nothing else bandwidth intensive like a hard drive connected to the usb port right? Can we see what the output of "lsusb" and "lsusb -t" is?

What happens if you reduce the USB cam resolution from 640x480 down to 320x240? Does the problem remain?

What's the CPU load on the system like? What does the ouput of a "top" command look like while the problem is happening?

All the best Simon!

-- AlanFord - 17 Feb 2015

Also, I suggest to try not using motion threads, but rather run three separate motion processes.

Issue with picture corruptions when running more than one Logitech cameras were reported by some users:

http://www.lavrsen.dk/foswiki/bin/view/Motion/BugReport2011x06x24x150605

http://www.lavrsen.dk/foswiki/bin/view/Motion/SupportQuestion2012x02x27x155712

And splitting them into separate processes is a work around

-- TosiaraT - 12 Apr 2015