Low Frame Rate with Altair 183C v2

Discussion of features and issues relating to Altair Astro Cameras
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admin
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Re: Low Frame Rate with Altair 183C v2

Post by admin »

Hi,

the limit for this camera at full resolution is about 17fps. You can get faster frame rates by selecting a smaller ROI (in particular it's the height of the ROI that tends to affect the frame rate).

If you open the camera into AltairCapture, the live video mode defaults to a lower resolution (1824x1216) which does achieve a higher frame rate, but that is obviously a trade off of reduced resolution for higher speed. I believe that in this mode AltairCapture is bringing back every 3rd pixel horizontally and vertically from the camera, so you see the full capture area at much lower resolution.

Robin
ctoulson1
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Re: Low Frame Rate with Altair 183C v2

Post by ctoulson1 »

Yeah I think the point is that sharpcap appears to be capped in terms of frame rate and it cannot reach the same potential frame rate as the native Altair software with the 183c.I wondered whether the developers might be able to fix this as I prefer Sharpcap features.
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Re: Low Frame Rate with Altair 183C v2

Post by admin »

Hi,

I disagree - if you set the same settings on both pieces of software then you will get pretty much the same frame rate. The only exception to that is that SharpCap does not enable the lower resolution modes that AltairCapture does. These have limited use anyway as you are sacrificing resolution.

If you can find a case where this isn't true then please post screenshots showing the settings and frame rates in both applications and I will investigate further.

cheers,

Robin
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Re: Low Frame Rate with Altair 183C v2

Post by Gordon »

Hi,

to continue asking a few more questions on this. I've since increased my RAM to 16GB and dug around the laptop specs. It has a WD Blue 2.5" (2004) 1TB HDD with a AMD A6 - 9220 processor. The latest speed test in SharpCap yields 78Mb/s, I'm now thinking of changing the HDD to a 500GB or 1TB SSD. This should improve on the 78Mb/s and will it improve FPS?

I bought a GPCAM 290M and at 5 to 10 ms achieved the FPS in the attachment, I was hoping for more and seems to be going the same way as the 183C which I've got to assume is my laptop HDD limiting the flow of data?

Appreciate any help!
290M.jpg
290M.jpg (48.23 KiB) Viewed 205 times
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Re: Low Frame Rate with Altair 183C v2

Post by admin »

Hi,

the best way to check whether your hard disk/ssd is limiting capture rate is to watch how the FPS info changes as you start/stop capturing.

If you see something like this when capturing it means that your speed of writing to disk is a problem
(that is, the number of frames in use in the memory area rises to the maximum, after which the dropped frame count goes up)
disklimited.JPG
disklimited.JPG (14.89 KiB) Viewed 203 times



If you see this instead, you have no problem with disk speed
(here the number of frames in use remains low, the dropped frames count does not increase and the fps stays the same as when you were just previewing the image)
noproblem.JPG
noproblem.JPG (16.14 KiB) Viewed 203 times
Hope that helps,

Robin
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Re: Low Frame Rate with Altair 183C v2

Post by Gordon »

Hi Robin,

thanks for the reply and after performing the test you suggested it appears I don't have a write to disk problem. The number of frames remained low and even when it went it up (on the 290M) they were buffered and saved. I did this on the 183C and the 290M, the 183C didn't buffer no matter what the exposure or ROI and wouldn't go above 35 FPS. The 290M did increase FPS as exposure and ROI changed and I probably need to spend more time recording what I achieve on that camera.

Not sure where that leaves me now, me and others are finding the 183C will not achieve above 35 FPS on our different rigs no matter what we try.

I've used several different cables, I've checked its using USB3, I've spent hours cleaning up the disk and removing apps etc and increased RAM to 16GB, it would seem for no discernible gain. I've also changed the high speed cache from 1024 to 6894 using the same ROI, exposure etc and there was no difference in frame rate or anything else I could spot. Is the latter a red herring?

Thanks for the help

Gordon
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Re: Low Frame Rate with Altair 183C v2

Post by turfpit »

Gordon

viewtopic.php?f=35&t=2590

Using a 183C V2, Toshiba laptop, Win 10 64-bit, 8Gb memory, 500GB SATA2 drive, short USB3 cable plugged into USB3 port. For RAW8 SER capture at full res I get 17fps, with res at 1920x1200 (which I use for lunar imaging) I get 35fps.

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Re: Low Frame Rate with Altair 183C v2

Post by admin »

Hi,

these are the frame rates I can get with the 183M (which shoudl be identical to the 183C). These rates were while just viewing the image from the camera, not capturing.

8 bit (RAW8/MONO8), 1ms exposure time set, USB Speed 3
320x240 - 208fps
640x480 - 119fps
800x600 - 98fps
1600x1200 - 52fps
2720x1824 - 35fps
5440x3648 - 17fps

12 bit (RAW12/MONO12), 1ms exposure time set, USB Speed 3
320x240 - does not work properly (sometimes hits 208fps)
640x480 - 119fps
800x600 - 98fps
1600x1200 - 52fps
2720x1824 - 34fps
5440x3648 - 8.6fps

It would be interesting to see equivalent measurements from your setup, remember to set a very short exposure and maximum USB speed.

cheers,

Robin
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Re: Low Frame Rate with Altair 183C v2

Post by Gordon »

Hi Robin,

I'll do as you suggest and report back. One observation, your settings are USB speed 3. I'm assuming that's the setting in SharpCap? If so my highest setting is 2.

Cheers

Gordon
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Re: Low Frame Rate with Altair 183C v2

Post by Gordon »

Hi Robin,

this is what my 183C achieved at the same settings, please note USB speed 2 is my maximum in SharpCap.

8 bit (RAW8/MONO8), 1ms exposure time set, USB Speed 2

320x240 - 35fps
640x480 - 35fps
800x600 - 35fps
1600x1200 - 35fps
2720x1824 - 22fps
5440x3648 - 12fps

12 bit (RAW12/MONO12), 1ms exposure time set, USB Speed 2

320x240 - 9fps
640x480 - 9fps
800x600 - 9fps
1600x1200 - 9fps
2720x1824 - 8fps
5440x3648 - 5fps

all from viewing not capture.

Cheers

Gordon
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