"Disappearing" Frames

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Davidbr_48
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Joined: Mon Apr 19, 2021 11:17 pm

"Disappearing" Frames

#1

Post by Davidbr_48 »

Attempting to run Live Stacking, the frames were neither stacking nor ignored -- they did get counted. The timer bar (bottom right corner) was running 10 second exposures, but after each frame the exposure started again but the frame had "disappeared". What happened? Where was it hiding?
Davidbr_48
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Joined: Mon Apr 19, 2021 11:17 pm

Re: "Disappearing" Frames

#2

Post by Davidbr_48 »

clarification -- frames did NOT get counted, either as "stacked" or "ignored", but the timer bar (?) in bottom right was running....

Davidbr
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Re: "Disappearing" Frames

#3

Post by admin »

Hi,

it sounds like the camera itself was not responding properly - ie not capturing frames. Keep an eye on the numbers at the bottom left corner - if the 'Dropped Frames' count is going up then that is definitely the problem. If the normal frame count is going up and the dropped frames is staying at zero and you are still not getting stacked/ignored then something more serious is wrong.

Problems relating to cameras not responding often come down to USB related issues - see viewtopic.php?f=18&t=349&p=1556#p1556 for suggestions on how to deal with these.

cheers,

Robin
Davidbr_48
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Re: "Disappearing" Frames

#4

Post by Davidbr_48 »

The Dropped Frames count Normal Frame count both stayed at zero while the bottom right green bar kept cycling. Could be a cable problem -- I'll try another USB port, etc.
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Re: "Disappearing" Frames

#5

Post by admin »

Hi,

what camera are you using?

cheers,

Robin
Davidbr_48
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Re: "Disappearing" Frames

#6

Post by Davidbr_48 »

ZWO183. Usually, it works just fine.....
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Re: "Disappearing" Frames

#7

Post by admin »

Hi,

I just wanted to check the code for your camera - the ZWO code should definitely increase the dropped frame count if there is a problem (timeout) grabbing the frame). It's worth showing the SharpCap log while the problem is happening to see if anything interesting is being logged that might point to the problem.

Robin
padraigh
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Re: "Disappearing" Frames

#8

Post by padraigh »

I'm also encountering this issue.

I'm using a ZWO 183MC.

What happens is my system gets into states where frames start (as indicated by the green progress bar) but never finish - they simply restart.

I think there is also a race condition between the PHD2 guider and the imaging camera - when the guider is active, I cannot focus stars because Sharpcap won't update images when I set shorter SharpCap exposures. Star images reappear as live when I turn off the guider.

However, if I start Sharpcap frame captures before starting the guider, I have more success in avoiding the not-completing mode; it's almost as if there is a prioritization somewhere in the USB food chain that depends on the order in which devices are activated.

The problems(s) seem more frequent since I recently switched gear to use my C11 instead of my shorter focal length refractor and I needed to up the guider from 1.5s to 0.5s sampling.
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Re: "Disappearing" Frames

#9

Post by admin »

Hi,

how do you have the two cameras connected back to the computer? This sort of problem is most common when you have a setup where a single USB port feeds a hub that then feeds both devices. If you can bring both back to the computer to separate ports you might find that the problem goes away. If you need other things plugged in (mount, focuser, etc) and you absolutely need a hub, try to put the other devices on the hub along with your guide camera (which transfers much less data) and keep a separate cable run back to the PC for the imaging camera.

cheers,

Robin
padraigh
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Re: "Disappearing" Frames

#10

Post by padraigh »

Yes I am trying to feed 4 signals into a 4-port hub because my Microsoft Surface has only 1 usb port!

I might have to dust off my old laptop and split the load between the MS Surface and the laptop.

P
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