ZWO ASI385 Highspeed Frame Drops

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wcblack7
Posts: 26
Joined: Fri Nov 02, 2018 6:05 am

ZWO ASI385 Highspeed Frame Drops

#1

Post by wcblack7 »

Hi Guys,

I'm having an issue trying to use my ASI385 camera in highspeed mode in the most recent Sharpcap 3.2.
The camera works fine in the RAW16 color space with frame speeds up to 65 fps using the full sensor ROI... essentially no dropped frames.
When I switch to the RAW8 color space (which is required for highspeed mode), the camera starts acting a little unstable.

As long as I keep the ROI at something less than the full sensor (for example 1920 x 1080 which is just slightly less than the 1936 x 1096 full sensor), it seems to run fine at regular speeds, but when I switch to highspeed mode, it starts dropping a lot of frames, which of course drops the frame rate way below even 65 fps. I've tried changing the memmory settings, turbo USB settings, etc..., but with no luck fixing the problem.

I've narrowed it down to a SharpCap issue by trying the same set-up in ASICAP (ZWO's capture software). Using the same cables and same USB port on the same computer (Windows 10), the issue does not occur. In ASICAP with the highspeed mode on (RAW8), I can get frame rates upto 120 fps with the slightly reduced ROI. Please note that if I use the full sensor, even in ASICAP, it acts a little unstable with some dropped frames. However reducing the ROI to the next smaller level, I get essentially no dropped frames in ASICAP at 120 fps and even up to 200 fps with smaller ROIs.

I have noticed that the SC status bar at the bottom reports "3 of 1018 frames in use" when it is not dropping frames and it changes to "2 of 1018 frames in use" when it is dropping frames. However, I don't know if that's a possible cause or just a symptom. Also, I can achieve the 120 fps+ in SharpCap when I reduce the ROI to something very small (like 256 x 256 pixels). I've also noticed that if I keep the camera in this mode and try various ROI's the camera becomes more and more unstable and eventually stops responding, even when I switch back to RAW16. At that point I have to close and restart SharpCap to get the camera going again.

I've attached a screen shot from SharpCap that shows the camera settings. With these settings, the camera will flip back and forth between periods of dropped frames and periods of no dropped frames. This screenshot was early on so it is only around 10% dropped frames, but will climb to well over 50%. I've also attached the SharpCap Log I recorded shortly after it started dropping frames in this mode.

I noticed while I was previewing the attached screen shot that it is reporting the camera temperatuer at 76C! Which I do not believe is accurate for several reasons. When I opened the camera in ASICAP right afterwards, the temperature was reported at 32.7C and when I switch to RAW16 mode in SC it behaves normally... I'm not sure if this is a related issued.

Thanks!
Bill
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Re: ZWO ASI385 Highspeed Frame Drops

#2

Post by admin »

Hi, quick question – what you have the Turbo USB setting set to in SharpCap? Your symptoms sound very much like what you'd expect if that is set too high. If it is on manual then try setting it to auto. If it's already on auto then try setting it to manual and turning the setting down to lower value and see if that helps. If your camera has an overclocked option in the controls you might try turning that down too.

Cheers, Robin
wcblack7
Posts: 26
Joined: Fri Nov 02, 2018 6:05 am

Re: ZWO ASI385 Highspeed Frame Drops

#3

Post by wcblack7 »

Hi Robin,
Thanks for responding. I've tried adjusting the turbo USB settings to very low, auto, etc..., but no luck fixing the problem. What I really find strange is that it functions completely normal in RAW16 mode, but not RAW8... of course the high speed frame rate option is only available in RAW8, but even without that on, it seems to be more unstable using the RAW8 color space.

I've also notice when it starts dropping frames like this, that the reported temperature from the camera is also incorrect. Sometimes very low reported temperature and sometimes a very high reported temperature... The high/low seems random, but just incorrect.

Thanks again!
Bill
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Re: ZWO ASI385 Highspeed Frame Drops

#4

Post by admin »

Hi,

it does sound like poor USB communication issues. Have you taken your USB setup back to basics i.e. just a short USB 3 cable no hubs, no other devices etc. It would also be worth trying on a different PC or laptop if you can. Do also check out the hints in the troubleshooting USB issues page – you'll find the link at the top of this page.

Cheers, Robin
wcblack7
Posts: 26
Joined: Fri Nov 02, 2018 6:05 am

Re: ZWO ASI385 Highspeed Frame Drops

#5

Post by wcblack7 »

If it is a poor USB communication issue, wouldn't I also have the same issue with ASICAP (the ZWO capture software)?
On the same computer with the same cables, I don't seem to have the issue with the camera in ASICAP.
Of course ASICAP is not as capable as SharpCap, so it is less taxing on the CPU, but in either case the CPU is only at about 25% utilized overall.

Thanks again!
Bill
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Re: ZWO ASI385 Highspeed Frame Drops

#6

Post by admin »

Yes, good point!

How new is the version of ASICap that you are using? SharpCap is using a version of the ZWO SDK from September, but if you're ASICap version is newer then maybe you have fixes that have not yet made it to the ZWO SDK that is publicly available.

Cheers, Robin
wcblack7
Posts: 26
Joined: Fri Nov 02, 2018 6:05 am

Re: ZWO ASI385 Highspeed Frame Drops

#7

Post by wcblack7 »

Hi Robin,
That makes sense... The ASICAP version I'm using is v1.5 released on 11/15/2018... However I don't think it showed up on their website until early December. They've added a histogram and probably a few fixes.

By the way, I hope your recovery went well last month and happy Holidays!

Thanks!
Bill
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Re: ZWO ASI385 Highspeed Frame Drops

#8

Post by admin »

Hi Bill,

I will certainly keep an eye out for any new versions of the ZWO SDK that are made available and include them in SharpCap pretty quickly. Right now it looks like their website is down so I can't even check! :D

Cheers, Robin
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