Dither frames saved

Discussions, Bug Reports and Issues related to Beta versions of SharpCap
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DaveSD
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Joined: Wed Apr 22, 2020 11:41 pm

Dither frames saved

#1

Post by DaveSD »

Robin,
I just tried the beta for the first time. I am using the 11 June, 64 bit Pro version.
For every 600sec light frame stacked and saved, SharpCap also saved a dither frame.
Dave
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Re: Dither frames saved

#2

Post by admin »

Hi Dave,

I've been trying to make this bug happen at my end to understand how it comes about. Can you give me a bit more info please?

* Camera make/model
* dithering settings
* dithering application (PHD?)

cheers,

Robin
DaveSD
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Joined: Wed Apr 22, 2020 11:41 pm

Re: Dither frames saved

#3

Post by DaveSD »

ZWO ASI294MC-Pro camera
600sec exposures
Automatically dither (checked)
Dither interval 600sec
Reduce exposure while dithering (checked)
PHD2 version 2.6.9dev5

This is all the same as when running SharpCap 3.2, and this didn't occur.
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Re: Dither frames saved

#4

Post by admin »

Thanks, I will test this setup (or as close as I can get).

Robin
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Re: Dither frames saved

#5

Post by admin »

Hi Dave,

thanks - I think I have this sorted now. The key was testing with a ZWO camera, as the way the camera responds to the 1s => full length exposure change can lead to a frame being generated that is marked as having had the full length exposure, but actually was only exposed for ~1s. This was the frame being saved (in my testing it happened about every 3rd dither).

I've made a number of changes to address this, including setting the exposure while dithering to 2s instead of 1s (this keeps the ZWO camera in still mode rather than switching it to video mode, which helps avoid that situation). The live stacking code also checks the time between successive frames to spot any frames that arrive that are not as long as they claim to be.

While testing this, I noticed that the time until the next dither only updates at the end of each frame, which is not useful for very long frames, so I fixed that too.

Let's hope I didn't break anything!!!

cheers,

Robin
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