[solved] Events have 'zoomies'

[lyallp]

Sometime in the last 3-4 days, ZoneMinder 1.37.16 on Gentoo linux started showing events with zoomies.

By Zoomies, I mean a 30 second event will show a couple of seconds in fast-forward, then return to normal speed, and maybe, later, speed up again and then return to normal speed.

It's not deal breaker, just an FYI

Firefox running on the machine which is running zoneminder, using Apache.

OPT_FFMPEG enabled.
FFMPEG_OUTPUT_OPTIONS=-framerate 25
MPEG_LIVE_FORMAT=m4v,
as is MPEG_REPLAY_FORMAT

Solved:
consistent framerate for recording and playback helps - see subsequent post.

[lyallp]

Upon further reflection, I did change the video camera Maximum FPS to 5fps and Alarm Maximum to 30fps.
The camera is a Logictec C922 USB Web Cam (a local camera?)
I was trying to reduce the CPU load on ZMC, whilst I was successful in that, the 'zoomie' effect appeared.
Would this cause the 'zoomie' effect?
Is ZMC buffering at 5 frames a second but alarming at 30 frames per second and the switch between the two is what is causing the 'zooming' effect?
During an event, some frames are not alarming because I have a period of time after the last alarm frame that I record. Could it be these intra alarm-frame frames are stored at a lower frame rate, thus causing the effect?

[iconnor]

Possible. If so, should be easy to replicate/diagnose.

[lyallp]

Interesting.

zoneminder-settings.gif (14.73 KiB) Viewed 588 times

I was not prompted for these previously when setting the camera.
Given they don't have a help '?' link, I guessed their purpose (rather than do the right thing and find the documentation)

However, I have the following settings, which I either changed or was prompted to enter.

Analysis FPS 10
Timestamp Label X 0
Timestamp Label Y 0 (although, these subsequently display as blank and thus will re-prompt for input)
Image Buffer Size (frames) 30
Maximum Image Buffer Size (frames) 90
Pre Event Image Count 30
Post Event Image Count 30
Stream Replay Buffer 90
Frame Skip 0
Motion Frame Skip 0 (although, these subsequently display as blank and thus will re-prompt for input)

FFMPEG_OUTPUT_OPTIONS = -framerate 30 (matching camera options)

I will report back once a few events have recorded.

[lyallp]

Ok, definately having a consistent framerate between cameras, recording and playback seems to be required.
I no longer have 'zoomies' if I keep my recording and playback at the same framerate.
Having analysis at only 10 FPS keeps cpu down, which was my intention, initially.
Playback is nice and smooth again.