Motion - Support Question 2006x 02x 26x 203712

sync error in proc 193: Input/output error


Hi, im running Motion 3.2.4 on a netgear WGT634u wireless router. Im not sure if you can help me here because of the platform i am using but i CAN use motion with a single USB cam. However I'm in the process of threading more onto it via a powered USB hub. when I run motion with the thread files heres what i get...
root@sjcWGT:~# motion -n -c /home/netmon/motion.conf
[0] Processing thread 0 - config file /home/netmon/motion.conf
[0] Processing config file /usr/local/etc/thread2.conf
[0] Processing config file /usr/local/etc/thread3.conf
[0] Thread is from /usr/local/etc/thread2.conf
[0] Thread is from /usr/local/etc/thread3.conf
[1] Thread started
[2] Thread started
[0] motion-httpd/3.2.4 running, accepting connections
[0] motion-httpd: waiting for data on port TCP 8080
[1] Started stream webcam server in port 8081
[2] sync error in proc 193: Input/output error
[2] Started stream webcam server in port 8082
[2] mcapture error in proc 193: Device or resource busy
[2] Video device fatal error - terminating camera thread
[2] Thread exiting
[2] Somebody stole the video device, lets hope we got his picture: Device or resource busy

im not sure how to attach my original .conf file..but nothing on it is changed except that it is running v4l in the video device.

my first thread is...
videodevice /dev/v4l/video0
webcam_port 8081
my 2nd is...
videodevice /dev/v4l/video1
webcam_port 8081

why am i getting this error?...and what do I have to change to fix it?

Please put your console output, config file text, text from logs etc
between the two VERBATIM tags and not outside to ensure that you get
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Motion version: 3.2.4
ffmpeg version:  
Libraries: ffmpeg, mysql, postgresql
Server OS: Open WGT for the WGT634u

-- StevenBlazekovich - 26 Feb 2006


Since Open WGT is basically a subset of Linux, that should not (in itself) cause any problem.

Your comment "nothing on it is changed except that it is running v4l in the video device" has confused me just a little - what was being done differently when it was working with a single camera? Also, what specific type of camera are you using? Are both cameras the same type?

-- BillBrack - 27 Feb 2006

Yes. Bill is probably thinking what I am thinking.

We have had many reports on two USB cameras not working simultaneously. I have the same experience.

The reason is that camera are normally USB1.1. And that sets the speed of the USB port to 11 Mbit max. And this is easily what ONE camera needs to run.

USB hubs do not help much in this respect. When I run more than one USB camera I have one USB controller card per camera. Or I use a special card that acts like 4 individual USB controller with full bandwidth on each.

-- KennethLavrsen - 27 Feb 2006

Followup Q&A

New Support Request also posted here SupportQuestion2007x03x10x105741

Kenneth, Can you provide more information on the "special card" that has multiple bus/contollers? I'm trying to find the best solution for this same problem, I have about 6 cameras but can only use 2 at the moment with the two built in bus/controllers. For example does this have one controller with 6 ports, or 6 controllers??

Another interesting potential solution I've run accross is:
  • Finally per find "USB bus problems". If you have multiple USB cameras on one bus then it can appear as if ZoneMinder is causing your cameras to fail. This is because the bandwidth available to cameras is limited by the fairly low USB speed. In order to use more than one USB camera with ZoneMinder (or any application) you will need to inform the driver that there are other cameras requiring bandwidth. This is usually done with a simple module option. Examples are usb_alt= for the OV511 driver and cams= for CPIA etc. Check your driver documentation for more details. Be aware however that sharing cameras in this way on one bus will also limit the capture rate due to the reduced bandwidth.

I haven't attempted to set any of these module options but will update this page when/if I discover a way to connect 2 cameras with degraded bandwith. This could be handy in situations where you might have a long chain of expensive repeater cables and want to stick a pair of cameras out at the end of it rather than having seperate cable runs...

-- RyanFulcher - 10 Mar 2007

Hi, I have been using Motion on a Linksys NSLU2, which is the kind of hardware you have (a low power CPU, mine is Intel PXA255 type, yours is Broadcom).

I use netcams, so cannot directly give advice on the USB cameras you are using. However, I find that with my server hardware (bogomips=300 approx) I can only run one camera and keep decent motion-detection ability. This is due to the CPU in the Linksys NSLU2 not having a floating point processor (fpu) - it uses 'softfloat' instead. This causes Jpeg decompression to be slower than on a x86 CPU (for example) or anything else with a hardware fpu.

I have in the past run 2 netcams on the NSLU2, but found that the motion-detection rate dropped to below 1 per second and I did not reliably detect events (in my application). This was not good enough for me, but it might be acceptable to you.

You can use the StatisticsDataPatch patch to find out, among other information, the MotionThruPut of a camera on any setup. That number is the number of motion-detection frames per second, which is often less than the camera's fps on some hardware. In my case it was due to the Jpeg-processing limitation I mentioned above.

This may help, in a roundabout way. It might be worth checking that your router hardware has the CPU power (and fpu, or lack of) to run the number of cameras you intend, and your fps requirement.

-- SimonW - 16 Mar 2007

-- AngelCarpintero - 02 Jun 2008
Topic revision: r7 - 02 Jun 2008, AngelCarpintero
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