Pixel shifting

A place for discussion of topics that are not specific to ZoneMinder. This could include Linux, Video4Linux, CCTV cameras or any other topic.
Post Reply
denver_compdoc
Posts: 7
Joined: Sun Jun 14, 2015 3:32 pm

Pixel shifting

Post by denver_compdoc »

I have a few wired Lorex cams with this problem, but this happens with other cams as well. I have a short video that shows the problem, but its 100MB so I cant upload it here.
If you could watch it, every few moments you'd see the image shifting just a few pixels one way and then another, also the image can darken and lighten a little during the shifts.
Using a variable bit rate and high Max Bit rate seems to help, but this shifting can trigger alarms in some zones.
Im wondering if there are brands of outdoor wired cameras that have absolutely steady images, or if theres a setting in the cam that might help? btw, in the Lorex gui, theres no i-frame setting.
mikb
Posts: 600
Joined: Mon Mar 25, 2013 12:34 pm

Re: Pixel shifting

Post by mikb »

denver_compdoc wrote: Tue Feb 06, 2024 4:18 pm I have a few wired Lorex cams with this problem, but this happens with other cams as well. I have a short video that shows the problem, but its 100MB so I cant upload it here.
If you could watch it, every few moments you'd see the image shifting just a few pixels one way and then another, also the image can darken and lighten a little during the shifts.
Using a variable bit rate and high Max Bit rate seems to help, but this shifting can trigger alarms in some zones.
Im wondering if there are brands of outdoor wired cameras that have absolutely steady images, or if theres a setting in the cam that might help? btw, in the Lorex gui, theres no i-frame setting.
Are you 100% sure it's not the camera moving? :)

To try to upload a shorter video, if you don't have a video editor to hand, you could try using FFMPEG, e.g. something like ...

ffmpeg -i INPUT.MP4 -ss 0:00:00 -t 0:00:00 -acodec copy OUTPUT.MP4

where INPUT.MP4 and OUTPUT.MP4 are the original and shortened file, and -ss is followed by a timestamp to skip to (e.g. junk the first minute with -ss 0:01:00) and -t is followed by how-long-to-keep (so the next thirty seconds after the skipped video -t 0:0:30)
Post Reply