Live Stacking Issues With Revolution Imager R2

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RMSQueenMary
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Live Stacking Issues With Revolution Imager R2

#1

Post by RMSQueenMary »

I have Revolution Imager R2 and use Sharpcap. I use Nextbook with Windows with Windows 10. I am using USB video adapter that came with Revolution Imager R2. When I do live stacking here is an example of one.

[USB Video Device]
Frame Divisor=128
Resolution=640x480
FPS=5.00
Colour Space=MJPG
Brightness=112
Contrast=128
Hue=0
Saturation=120
Sharpness=3
Gamma=1
Gain=16
TotalExposure(s)=310.161
StackedFrames=740

I have 740 frames stacked with total exposure of 310 seconds, which is 0.42 seconds per frame. I would expect the total exposure to be 3,788.8 seconds or 63 minutes. This is despite the fact I have lowered FPS to 5 and set Frame Divisor at 128, which says 5 seconds.

What could be going on and what could be done?
Last edited by RMSQueenMary on Tue Jan 16, 2018 2:54 am, edited 1 time in total.
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Re: Live Stacking Issues With Revolution Imager R2

#2

Post by admin »

Hi,

With devices like the revoloution imager, SharpCap does not know the true exposure of each frame it stacks, so it is supposed to estimate the total exposure based on the gaps between frames that get put into the stack. I'm not sure that this is working correctly in this case :( I strongly suspect that the only real problem is that the Total Exposure time in the capture settings file is wrong and that everything has worked correctly otherwise. If it actually took 63 minutes to build the stack then that ties nicely with your 740 frames to 5s per frame.

It looks like you are either running SharpCap 2.9 or older, or you are using the old 'DirectShow Pipeline' option in 3.0, which means that control over frame rate in these circumstances isn't as good as it would be in SharpCap 3.0 using the 'SharpCap Pipeline' for directshow - this allows you to limit the frame rate in a more accurate manner which I suspect would also fix the total time being recorded incorrectly.

cheers,

Robin
RMSQueenMary
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Re: Live Stacking Issues With Revolution Imager R2

#3

Post by RMSQueenMary »

admin wrote: Mon Jan 15, 2018 8:23 pm Hi,

With devices like the revoloution imager, SharpCap does not know the true exposure of each frame it stacks, so it is supposed to estimate the total exposure based on the gaps between frames that get put into the stack. I'm not sure that this is working correctly in this case :( I strongly suspect that the only real problem is that the Total Exposure time in the capture settings file is wrong and that everything has worked correctly otherwise. If it actually took 63 minutes to build the stack then that ties nicely with your 740 frames to 5s per frame.

It looks like you are either running SharpCap 2.9 or older, or you are using the old 'DirectShow Pipeline' option in 3.0, which means that control over frame rate in these circumstances isn't as good as it would be in SharpCap 3.0 using the 'SharpCap Pipeline' for directshow - this allows you to limit the frame rate in a more accurate manner which I suspect would also fix the total time being recorded incorrectly.

cheers,

Robin
Thank you Robin for the reply.

I am using SharpCap 2.9. I have not updated to 3.0 yet. I updated Windows 10 and prior to the update, it said USB2.0 PC CAMERA.

The total exposure time is 310 seconds, which is a little over 5 minutes.
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Re: Live Stacking Issues With Revolution Imager R2

#4

Post by admin »

I would suggest giving 3.0 a try and using the 'frame rate limit' control - if the total time and frame count still don't line up for you then, let me know.

cheers,

Robin
RMSQueenMary
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Re: Live Stacking Issues With Revolution Imager R2

#5

Post by RMSQueenMary »

Just downloaded Sharp Cap 3.0 and did everything suggested. I am still having the same problem. 1 frame is not 5.12 seconds despite R2 set at 5.12 seconds. If I get 100 frames, I get total of 52 seconds, not 512 seconds or about 8 minutes.

The DiresctShow Cameras via SharpCap Pipeline is grayed out and cannot be selected.
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Re: Live Stacking Issues With Revolution Imager R2

#6

Post by admin »

Odd, as there is no code to disable that radio button in SharpCap 3.0 - it should look like this
Capture.PNG
Capture.PNG (28.01 KiB) Viewed 13408 times
Not sure that you would get the right total time even if you get that enabled anyway, although the chances are better I think. It's actually a good idea with devices like the Revolution to run SharpCap live stacking at a higher rate than the camera - that would mean that every frame from the camera gets stacked several times. The reason for this is that there is some noise from the A->D conversion in the frame grabber, and that noise will be different in each grabber frame, so stacking several grabber frames for each camera frame helps reduce the impact of that noise.

cheers,

Robin
RMSQueenMary
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Re: Live Stacking Issues With Revolution Imager R2

#7

Post by RMSQueenMary »

admin wrote: Sat Jan 20, 2018 11:38 pm Odd, as there is no code to disable that radio button in SharpCap 3.0 - it should look like this

Capture.PNG

Not sure that you would get the right total time even if you get that enabled anyway, although the chances are better I think. It's actually a good idea with devices like the Revolution to run SharpCap live stacking at a higher rate than the camera - that would mean that every frame from the camera gets stacked several times. The reason for this is that there is some noise from the A->D conversion in the frame grabber, and that noise will be different in each grabber frame, so stacking several grabber frames for each camera frame helps reduce the impact of that noise.

cheers,

Robin
I did use that configuration and same problem happens when I set to 5 seconds. When I get 100 frames stacked, total exposure is 25 to 30 seconds, which is 0.25 to 0.3 seconds per frame. If it is 100 frames, I should get 500 seconds.
Danoglide64
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Re: Live Stacking Issues With Revolution Imager R2

#8

Post by Danoglide64 »

I haven't gone far enough to have any problems Live stacking yet, my question is about the picture posted showing Sharcap settings, Direct show.
That's not even showing up on my Sharpcap version.
Screenshot (19).png
Screenshot (19).png (173.89 KiB) Viewed 13092 times


I have started getting more familiar with the settings listed in the Revolution Imager's website on How do I see DSO's and then adjusted the settings in Sharpcap but the Histogram looks terrible, all the colors are slammed all the way to the left and I just can't seem to get this part under control.

Thanks for any advice,
Danoglide
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Re: Live Stacking Issues With Revolution Imager R2

#9

Post by admin »

Hi,

the settings page to choose between the two ways of dealing with DirectShow devices was removed in SharpCap 3.1 because the old way of doing things was also removed, so there was no need to have a choice any more.

Probably best to post a screenshot showing your histogram troubles (and the image being captured too) and hopefully we can advise.

cheers,

Robin
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