Slow Motion event viewing

[RoatanBill]

I have IP cameras. My Source has an empty Maximum FPS as suggested in the Wiki. I also left Alarm Maximum FPS empty, at least to start.

I aimed a camera at a large monitor that displayed a large Digital Clock ticking off the seconds. I let it run about a minute. When checking the event, I have 1100 alarm frames. When I view this event all looks as expected. The statistics say that the camera is producing 15.21 fps.

I then changed the Alarm Maximum FPS = 5 and reran the test. Now the alarm frames are much reduced, which is what I was trying to do to save disk space. Examining the files, I'm getting 5 alarm frames per second.

However, when I play back the second event, it plays back in slow motion, it takes about 3 minuted to view the digital clock ticking away one minute. I reduced the frame count to a third of what it was and now the playback is 3 times as long.

Why is the event playback taking so long. I expected a somewhat jerky digital clock that would complete in about a minute - real time. What I get is a slow motion playback which is useless.

How is one supposed to reduce the frame count to save disk space?

[mikb]

I think the answer is -- you don't!

For an IP camera you set the frame rate at the camera end, and leave the boxes BLANK on ZoneMinder. Otherwise it gets confused.

Your camera will be still sending 15fps approx -- there's no way for ZM to tell it to change rate.

You've told Zoneminder that it's actually 5fps "in alarm", so I guess your alarm events will go at 1/3rd speed

Saving disk space is *so* last century. Get a bigger disk

Or more realistically -- tune the motion detection so it only records motion you need, a ticking clock is quite a lot of motion, that wouldn't happen in real life. Would it? What are you trying to motion detect, a busy street/corridor?

[RoatanBill]

I've got a 4TB drive dedicated to zoneminder. I also have 4 IP cameras. The reason I pointed it at a moving clock was to get accurate statistics about what I was seeing. Everything looked slow motion, but I didn't know how slow. The moving clock made the timing absolutely clear.

This is at a departures gate at a small international airport, with people milling about so modect is really triggered almost continuously every time there's a flight leaving. It amounts to Record for about 2 hours, then almost nothing for 2 hours and then Record again for a while, depending on day of week and time of day.

The cameras have no frame rate adjustment (FOSCAM FR4020A2). I didn't know enough about IP cameras to look for ones that are frame rate adjustable.

When I look at the files in the second case, I only have 5 frames per second stored on the drive as per their time stamps. In the first case I have 15. Therefore, Zoneminder must be filtering the 15 frames coming in down to 5 frames. The disk space used is definitely much less that when I had a blank Alarm setting. So, I'm getting a significant reduction in disk consumption. It's only on playback that it's messed up.

Something isn't adding up.

[mikb]

See :-

http://www.zoneminder.com/wiki/index.php/Foscam

Scroll down to the "&rate=D" bit, try appending that to your URL to control the frame rate. Does that help?

Things aren't adding up because you are telling ZoneMinder to access the camera at 2 different frame rates, yet the camera seems to be defaulting to a constant rate. This will cause problems.

I think you need to empty the frame rate settings on ZoneMinder.

The frame rate settings are intended for local cameras (USB, BT848 capture cards) and don't work well with IP cameras that stream video at the rate they have been configured to.

[RoatanBill]

Yes - That helps. Thank You very much.

I looked throughout the Foscam users manual and couldn't find any reference to a frame rate parameter. You would think that the user guide should include that, but it certainly doesn't.

There appears to be a typo on that table. A D value of 15 is listed twice. I only saw the first one and figured I'd get 3fps. I only got 1fps. Then I looked at the table again and noticed that the 15 was listed for both 1 and 3fps.

Someone that has access to that html page might want to fix it so it says 13 = 3fps.

Now I can experiment with various camera settings to see what's reasonable for video quality versus disk consumption.

Again, Thank You very much.