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Camera locks up after rapid calls to PositionSet (C90)

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This document was generated from CDN thread

Created by: Frode M on 15-11-2011 02:45:11 PM
Hello,

I'm integrating with a C90 and writing an application for letting users set camera position using absolute coordinates (i.e. "xCommand Camera PositionSet...." instead of "xCommand Camera Ramp...").

The idea is to allow the user precise control of the exact position (even in the case of high latency) , instead of having to do ramp-stop-rampbackwards-stop type adjustments.

It appears that sending a stream of "xCommand Camera PositionSet..." calls in rapid succession eventually causes the camera to lock up: The camera does not move at all in response to either PositionSet or Ramp commands, but these commands initially keep reporting success. Only after a while does these commands report back with error (reason "unknown"). Finally, after a while (a minute or two, perhaps) the camera appears to reboot internally, resets to default position, and starts accepting commands again.

Is this a known issue? I guess we can work around this by throttling the amount of PositionSet commands - inserting a minimum delay between any two calls, but this causes undesirable additional latency.

(There is only one 1080p 12X camera connected to the C90).

Any suggestions are very welcome

Subject: RE: Camera locks up after rapid calls to PositionSet (C90)
Replied by: David Bruun-Lie on 07-12-2011 12:30:25 PM
Hi Frode,
sorry for the late response. Can you specify what you mean by "rapid succession"? 10 per second? 100? 1 every second?

This is not a known issue. What sw version is on the codec and on the cameras? (use xstatus camera to get camera sw version)

Regards,
David

Subject: RE: Camera locks up after rapid calls to PositionSet (C90)
Replied by: Frode M on 07-12-2011 12:57:37 PM
Hi,

right now I do not have immediate access to the c90 unit, so this is from memory. I could probably get back to you with exact version details later. In any case I believe we have observed this behavior on several versions, I think we tested on 4.2 and an early-access 5.0 beta at the very least.

The rate of commands to trigger this is around 5, 10, 20 per second, I guess, for a period of 10-30 seconds. Typically each positionset command represents a fairly small movement distance (imagine dragging a slider with a mouse, with each mousemove event triggering a new positionset).

Also! This may or may not be related, but I recall observing a similar effect even when using far end camera control over a VC call between two C90 units. In that case, only a few farend camera ramp commands (farend doesn't support positionset, only ramp commands) per second for a short amount of time (10-30 sec) seemed to cause the remote end camera to freeze, then reset to default position. I did not have a chance to observe the far end camera or unit during that incident.

If this is insufficient information for you to be able to reproduce this, we can probably try to produce device logs and a more detailed description - although during our testing, "blasting" a series of positionset commands for a short while always seemed to cause a lockup sooner or later.

Subject: RE: Camera locks up after rapid calls to PositionSet (C90)
Replied by: David Bruun-Lie on 07-12-2011 01:04:06 PM
Ok, interesting usage ;-)
I will ask the camera team to have a look at this.

Regards,
David

Subject: RE: Camera locks up after rapid calls to PositionSet (C90)
Replied by: Frode M on 16-01-2012 09:45:56 AM
Hi again,

did you hear anything about this from the camera team? :-)

Regards,
Frode

Subject: RE: Camera locks up after rapid calls to PositionSet (C90)
Replied by: David Bruun-Lie on 16-01-2012 04:06:16 PM
Hi Frode,
got a reply now and that is that the API is currently unable to handle that type of request-bursts that you are describing. So my only suggestion is that you drop the frequency of commands to a rate that the codec can handle. Unfortunately I cannot give you a figure for what exactly this rate can be as it would depend per type of command.

Regards,
David