7 CM3 cameras dropping frames

Answered

Varun Narasimhan

• June 13, 2023 18:33

I have a series of 8 CM3-U3-31S4C-CS cameras that I am trying to get synchronized images from.

For my application, a frame rate of at least 50 Hz is necessary for suitable recordings and i need the playback to play in real time.

Up until 6 cameras, I have found settings that allow me to produce images that are quite synchronised, differing by a max of 2-4 frames in length which appears to be negligible given that the playback files show identical durations.

However, once I put the 7th camera, at least 3 of the cameras end up playing at double the speed and have half the duration. In other words, frames are getting dropped.

I tried reducing the exposure to its smallest possible value but this effect persisted.

Using the suggestion in this link: my setup drops frames when using multiple gige cameras – FLIR Systems (zendesk.com)

I tried reducing the device throughput limit from its maximum 177408000 to 117216000. When I did this, all the cameras were synchronized but again played at double the speed of real time video

Are there any suggestions for this?

 

Thanks,

Varun

0

• Official comment

  

  TDY_Demos

  Community team

  • September 13, 2023 20:44
  • Edited

  

  Hello Varun,

  Reducing the DeviceLinkThroughputLimit will reduce the bandwidth allocated to each camera, which will essentially decrease the framerate.  It sounds like by decreasing it, your framerate is about half.  When you record, if you still try to record with a fps setting of 50Hz, but your cameras are running at 25Hz, your video will look twice the speed.

  If you were using SpinView, when you record a video, you can enter a framerate or ask it to use camera framerate.  I would use the camera framerate for your recordings to look like real time.

  As you are using third party software, I am not sure what options they have.  They may be recording the avi's with a set framerate that is higher than the resulting camera framerate.

  You could also be dropping frames if your software can not keep up with so many cameras.  We have a light weight recording example in Spinnaker to verify if you can capture from all cameras at full framerate or not.  It is called AcquisitionMultipleCamerasWriteToFile.  You can use this example to verify if you can record from all cameras with out dropping frames to verify your hardware.  If that works, then the bottleneck would be in the software and you can start looking at those options.

  Demos

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