Pre-trigger frame buffer setting

105437

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I would like to have 1 second included in the alert clip right before the first motion detected. What should I set the pre-trigger in order to get this? My cameras are running at 15 fps so would 15 be the right setting? Thanks!
 

fenderman

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What was the cpu usage before?

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fenderman

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Are you using direct to disc?

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fenderman

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You need to use direct to disc

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fenderman

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When you set direct to disc.. Make sure your cameras I frames matches the fps... Set the pretriggeer to 30 and you will be fine

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bp2008

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What fenderman said.

Also make sure the frame rate is set in each camera's web interface, not in Blue Iris. The frame rate setting in Blue Iris doesn't work anymore.
 

105437

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Thanks guys... Both cameras are set to 15 fps and the pre-trigger frame buffer is also set to 15 with direct to disc. BI is running stable around 65% - 70%.
 

bp2008

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With direct to disk, recording can only begin on an iframe, so you may lose up to one entire i-frame interval worth of frames from your pre-trigger buffer. So whatever your iframe interval is set to, add that number to your pre-trigger frame buffer.

For example, if your iframe interval is 30 and your FPS is 15, and you want one second of video before the motion trigger, then you need a pre-trigger frame buffer size of 45. (15 frames = 1 second, plus 30 for the iframe interval). This will result in you getting 1 to 3 seconds of video before the motion trigger. The amount of pre-trigger video will vary between 1 and 3 seconds depending on the timing of the motion trigger compared to the timing of the iframes in the video stream.
 
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