Drastic drop in FPS

Discussions of using SharpCap for Planetary Imaging
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Neaptide
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Drastic drop in FPS

Post by Neaptide » Sun Aug 04, 2019 6:33 pm

I'm having trouble understanding what is going on with my frame rate when using Sharpcap3.2 and my asi224mc while planetary imaging. I'm hoping some of the pros on this forum can explain what's going on and if I need to do anything different.

I'm using an exposure time of ~2.2ms and a ROI of 640x480 which is giving me a frame rate of ~130fps. My frame rate holds steady for the first 1600 frames with 0 dropped frames. After 1600 frames my frame rate drops to ~30 fps and I'm dropping a massive amount of frames. When I stop the capture a window pops up saying that it's writing the buffered frames, which is over 1000 frames. I've turned off the High Speed mode setting and adjusted the Turbo usb mode with varying amounts of improvement.

Should I be worrying about this being that there are a significant amount of frames that get added during the buffered frame writing process?

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turfpit
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Re: Drastic drop in FPS

Post by turfpit » Sun Aug 04, 2019 11:47 pm

Follow the steps in this viewtopic.php?f=18&t=349&p=1556#p1556.
Are you capturing AVI or SER format? What is the cabling between camera and laptop (length, intermediate hubs etc)? Post a camera settings file.

Dave

PEM1
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Re: Drastic drop in FPS

Post by PEM1 » Mon Aug 05, 2019 2:59 pm

I had a similar problem that turned out to be for a trivial reason. I was using Dropbox and my home network eventually couldn't keep up with the uploads. I now pause the sync to Dropbox when capturing images.

Neaptide
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Re: Drastic drop in FPS

Post by Neaptide » Mon Aug 05, 2019 7:45 pm

I solved my usb issues by using a smaller ROI and also setting my max frame rate to 120fps in order to avoid overwhelming my usb. Last night I was getting 110 fps with the new settings while imaging Saturn. Thanks for the help.

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admin
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Re: Drastic drop in FPS

Post by admin » Mon Aug 05, 2019 8:50 pm

Hi,

If the dropped frames are only a problem while capturing then it may simply be that your hard disk is unable to keep up with the rate at which the data is coming from the camera. SharpCap's built-in buffering will help for a while and you will notice the number of frames in use go up until it reaches the maximum and then frames will begin to drop.

If this is the case then the options are to reduce the frame rate or ROI or to buy a faster hard disk or SSD!

Cheers, Robin

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