SharpCap Forums

Hi all,

I'm trying to use SC for solar capture and need to use a very high framerate (1.5-5ms). I'm getting thousands of dropped frames even though I have an SSD and the memory buffer is as high as it can go on my system (3GB). Strangely, I get zero or very few dropped frames when using ZWO's ASICap software. This tells me the camera, USB, hard drive, and RAM on the system should be sufficient for high speed capture. Why would I be getting dropped frames in SC and not ASICap?

I'm also finding that my PC starts to bog down to the point of locking up after leaving live view on for more than a few minutes. Capture was not actively recording.

I prefer SC for many obvious reasons so would like to figure this issue out. Please let me know if you have any advice.

Thank you!

Details:
SC Version: 4.0.9268 64bit
PC: MeLe Quieter3Q
CPU: Intel N5105
RAM: 8GB
SSD: Samsung EVO M.2

Hi,

so the first thing to check is if the dropped frames only happen when you are capturing, or if they happen when you are just watching the image on screen. If they only happen while capturing then it is most likely that the disk is not managing to keep up with the rate that data is being sent to it.

In the case of dropped frames while capturing, you will most likely see the following :

* No dropped frames initially when you press start capture
* The memory 'frames in use' counter in the status bar will gradually rise until almost all frames are in use
* At that point, you will start to see dropped frames
* When you stop capture, you will see a countdown as the buffered frames are written to disk.

If this is what you see then it may be worth clearing out some space on your SSD and running the Windows optimize tool on it - this helps make sure that the free space on the disk is wiped ready for quick writing - an SSD that has not had this done and has been close to full in the past can actually be quite slow as it needs to clear each block before writing data. Also, increase the memory setting for 'high speed frame cache' to the maximum possible if you have not already.

If you are seeing dropped frames while just viewing the image then you need a different approach - check the SharpCap log, it will record dropped frames with a category and count for that category, which will help diagnose what the cause is.

From the point of view of comparing with ASICap, make sure all camera settings are the same (including things like Turbo USB settings). Also, measure how many frames you can capture to file in a set time (say 30s) with each program to see if the difference is real or if it is just a reporting difference (maybe ASICap doesn't report dropped frames in the same way SharpCap does).

cheers,

Robin