Distortion in Sighthound video

[SydsVids]

The video shown in the Sighthound window often becomes distorted (mostly in the bottom half of the frame), triggering the recording of an “event”, resulting in a lot of such events being recorded. Searching the list for meaningful events becomes tedious to say the least. Comparing the realtime Sighthound video with the same camera shown in my browser shows that the distortion occurs only in Sighthound and therefore isn’t caused by the camera or the signal transmission over wifi. I read on a forum somewhere that the problem might be caused by a difference in resolution or frame rate settings between the camera (Foscam F19804W) and the Sighthound settings for that camera. I’ve tried every combination of these settings to no avail. I have another, older, camera (Foscam F18905W) that doesn’t experience the problem. If it might be helpful in resolving this, I can provide screenshots the settings available on the camera itself and in the Sighthound setup for the camera.

[Semper Vaporo]

This has been reported by others under other entries in this forum, but the titles usually don't lead one to thinking of the same problem... It has been described as "streaky" and "smeared" and some other terms.

The fix is usually to append the following:

?svforcetcp

to the end of the "Stream Path" data in the "Camera Setup" dialog of SightHound.

This forces the camera and computer to communicate in a mode that enforces the receipt of all data. It is a bit more data intensive on the network because each packet of the image is verified (and requested to be sent again if it is found to be missing or damaged) so the picture is always complete.

Without using TCP the camera is just sending data to the requestor (the program in the computer) and if something gets lost or garbled, the program in the computer loses track of what is being received and it gets the last packet from the data buffer over and over until it has a full picture. If you look at your posted image you will see that the streaking ("distortion") is just the last good line of the image repeated on every line to the bottom of the picture.

See: https://www.sighthound.com/forums/topic11559


On another note: The camera is basically performing two processes all the time.

One process is scanning the image sensor and building a picture in an internal buffer.

The other process is fielding requests from the outside world (network) to send that buffer to the program making the request. It is possible for two requestors to get the same image from the camera's internal buffer, but they get it in two totally different data streams over the same wires/WiFi; even if the two requestors are resident in the same computer! One data stream could get garbled and the other not so one program would get a messed up image and the other not... OR they both get garbled data, but one is using TCP protocol and requests a retransmit of the missing/garbled packet and so that one gets the proper whole image and the other exhibits some sort of problem.

I think that is what is happening with these Distorted/smeared/blurry images. It is normal to use the least data intensive method to transmit images on a network and usually that is sufficient but sometimes there are electrical noises in the area that can garble the data too often and then you must force the use of a method that guarantees the receipt of the data.

[SydsVids]

Thanks for the prompt and comprehensive reply. Your solution fixed my problem. I had been using Sighthound's preset for a Foscam F19802W since my F19804W wasn't listed, but that didn't give me access to the "stream path" so I went all generic, entering the IP address manually and using rtsp protocol (http wouldn't work).
I've had a similar problem with a D-Link DCS-942L on Vitamin D video and I remember now trying the fix of adding "?svforcetcp" to the "play1.sdp" stream path that was provided when I selected my camera from those listed as available. It wouldn't work. I've changed the location of the camera now so that it's closer to my wifi extender and it works ok most of the time now. I won't pursue the problem on that camera any further. Thanks again. Sure would be nice of all these cameras were "plug and play".

[Max]

Thank you Thank you Semper!

I have been struggling with this for months also on Sunell Camera's which aren't listed.
What an improvement.

Thanks,
Max

[Anjo206]

I also had the same problem with my Foscam FI9804W while on WiFi, so I decided to use powerline networking and it solved the distortion issue.

I have yet to try forcing the camera to use TCP while on WiFi however. I reasoned that since WiFi sometimes can be cutoff such as through deauthentication DDOS attacks it would be more reasonable to go with powerline networking if not direct ethernet.