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JeVois Freezing on PC and RaspberryPi

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I have my new JeVois and got started immediately creating a card from the latest image (http://jevois.org/data/jevois-image-latest-8G.zip) using jevois.org/start as instructed. I used Windows 10 + Win32DiskImager + SanDisk Ultra 16GB HC1 SD. I used USB 3.0 and a nice cable to power the JeVois. I used Windows "Camera" app and it connected immediately and I watched the entire intro video and played with the JeVois for about 10 minutes before the first freeze occurred. The video stream stopped; Windows remained functional. I removed power to the JeVois and let it restart. I was able to stream for only a few seconds before the stream stopped again. I then tried VLC and amcap with the exact same results. I used Hyperterm to monitor the serial output and While JeVois streams, I am able to communicate with JeVois. When JeVois freezes, the serial communication also freezes. One strange thing I noticed is when I "close" the frozen video stream (leaving Hyperterm connected), the serial communication resumes until I again open the video application and freeze the stream.

I decided to switch environments from PC to Linux. I connected JeVois directly to a RaspberryPI + GUVCVIEW, but was not able to connect until I used a USB Hub with external power. GUVCVIEW then connected, but the exact same freeze occurred a few seconds into streaming. I then attempted to reformat my SD card and put a fresh image. I formatted the card using a camera (I've had issues formatting SD cards on Windows 10) and then downloaded a fresh image and used Win32DiskImage to write to the SD card. I powered the JeVois and it freezes after a few seconds once again.

I hope that I am doing something fundamentally wrong and that there is a simple solution. But I have not been able to find any support regarding freezing video from JeVois and I would be surprised if I was alone unless I had defective hardware, maybe?

Please let me know if there are any further suggestions.

Thank you,

David B.
asked Mar 16 in Hardware Questions by dbnit82 (120 points)

1 Answer

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Hum, the fact that the serial connection still works when you close the frozen video would suggest that the transfer of video frames is choking somehow. Indeed, we handle serial communications in between video frames (send one frame, handle serial, send next frame, handle serial, etc).

Can you try some other, lower bandwidth video modes, for example

guvcview -f YUYV -x 320x120

This is the background subtraction demo at 30fps. Or maybe your USB cable is not so good?

answered Mar 16 by JeVois (5,150 points)
Very helpful, thank you. I played around with lower resolutions and there are certainly some settings that do not freeze at all. The larger the resolution gets, the quicker JeVois stops streaming; the time span ranges from working -> 10-12 seconds -> immediate fail.

I found the "thickest" USB cable I could find in my posession and it definitely helped. I also had success both with RaspberryPi and Windows with my trials.

It does appear that a "choking" effect is happening. Can you send a model/part number or picture of the USB cable you recommend? Is it likely this is a cable issue or a combination of other issues as well?
incidentally, we just experienced something similar with a local backer who just unpacked his camera. AMCap on Windows would work but after some time it also dropped the camera. If we re-opened it, it looks like the camera was still running (i.e., had not crashed).

We were connected to the front-panel USB ports. Once we connected directly to the USB ports on the motherboard of the host PC, the issue disappeared. So I am guessing some power or data integrity issues in that connection to the front panel might have been the problem.

If you are using a Y cable, can you try to connect the long end (power+data) to your Pi and the short end (power only) to a reliable USB charger that is rated 1A or more (or a USB battery bank or such)? That may solve the problem by providing better power.