Missing beginning of motion trigger events..

[erkme73]

After recently configuring my BI to use sub-streams, HW encoding, and limited decode features, I've managed to get my nearly 50 cameras to use as little as 10% CPU. Love it, grateful for it, but am wondering if I may have jumped the shark a bit.

The clips all seem to be starting mid-action. That is despite disabling object detection, and adding as much as a 4 sec pre-buffer. I've also decreased the I-frame interval from twice the FPS to equal to FPS (i.e. 20FPS, 20 iframe).

I suspect it has to do with the "limit decoding unless required" option that I've enabled on all cameras. I think I understand the concept, whereby the only frames that are "inspected" by the BI motion detection algorithm are the full frames (iframes), but even with them set to match the FPS, I'm still suffering from the delayed recordings.

If I disable all the decoding limits on all the cameras, I'm back up to 40% CPU - so there's definitely a CPU cost to leaving it off. But, capturing vehicle after it's already halfway down the street makes the clip completely useless.

Is there a way to increase the reaction time so that motion triggers capture the movement from the onset?

 

[wittaj]

You really shouldn't use the limit decoding. Read the wiki. Are you using direct-to-disc recording? Are you doing all the other optimizations called for in this wiki?

With the amount of cameras you have and the processor you have, 40% is not a large amount!

40% and capture everything or 10% and miss half of it?

A 4 second pre-buffer isn't a lot either...but that is just masking the issue you have created.

Optimizing Blue Iris's CPU Usage

Blue Iris uses a lot of CPU time. In most Blue Iris installations, your CPU is the limiting factor which determines how many cameras you can have. As such, it is extremely important to optimize your configuration to ensure you can get the most out of your system while consuming the least...

ipcamtalk.com

 

[erkme73]

Yes, I know, I've become addicted to the "how low can I get my CPU" rush. Thanks entirely to you!

Yes, D2D. I'll check the other optimizations now in the wiki. Increasing the pre-buffer seems to have zero impact on when the trigger actually starts recording - which is what's making me think it's the limit decoding. My inclination is to just turn that feature off, but I wanted to make sure I wasn't missing someting else that could mimick these symptoms.

 

[wittaj]

Yeah, getting the low CPU is addicting LOL.

Unless there is some other issue you have missed from doing in the wiki, I am fairly sure the limit decoding is the problem - it has lot's of issues and results in missed motion. Even if you have missed something from the wiki, limit decoding shouldn't be used. I think it's main benefit is if you record 24/7 and no trigger on motion. But it turns off whenever you log into the system, so it is a mask.