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Old 30-01-2014, 01:26 PM
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Camelopardalis (Dunk)
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Planetary capture laptop capture rates

Folks, I seek your planetary imaging wisdom...

I've just upgraded from a Neximage to a QHY5ii and while experimenting I noticed something weird with capture rates on my 2 year old ultra portable (AMD E-350 dual core with 4GB memory running Windows 7 64-bit)...

The old Neximage was limited in that it could only capture at low frame rates in lossless mode, and at 640x480. But that's a well known limitation of the camera.

The new QHY can, theoretically, capture at up to 30fps at max resolution in raw mode. When I use the bundled EZPlanetary it gives a read out in the bottom of the status bar that gives displayed and 'HDD' fps. I read on the QHY forum that some people can't display at full rate on older machines because they can't handle that much throughout over USB...but I get the full 30fps reading and it looks legit...I tested this looking at a swaying tree in the garden in daylight and the motion is smooth and natural just as with the naked eye. So, it looks like my machine can at least get the data from the camera to the screen!

Anyway, when capturing the displayed rate stays the same but the HDD value varies between 2 and 7 fps the software isn't reporting that it's dropping frames, and I get an output file with the number of frames requested, but how can I tell if the frames were all sequential and the machine was just buffering? What I really want to be sure of, before I go out in the field, is that I'm capturing every frame and therefore capturing the good seeing frames as well as the bad ones

But how can I be sure? How can I inspect the time code?

If it's a problem with my machine not having enough juice, then I can look into remedying that but I've ran a few disk benchmarks and it all comes I roses with write speeds between 86 and 111MB/s...which should be more than enough, as USB(2.0) can't carry that.

Any suggestions as to how I can check what's going on?

More generally, what's the preferred capture software for planetary?
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Old 31-01-2014, 10:22 AM
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pluto (Hugh)
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I find I get similar results. I have a QHY5L-IIc which is supposed to do 30fps @ 1280x960 (according to this: http://www.gamaelectronics.com.au/files/QHY5L2.jpg)
In EzPlanetary I get consistently 14-15fps. It's definitely not a hardware speed issue as it's the same on both my laptops. Both have SSDs and they're both very fast laptops, especially the new one. Same results on Win7, Win8 and Win8.1.
I've tried FireCapture and I get the same 15fps.
I've tried SharpCap and I've seen higher rates in that, up to 24fps, but it's inconsistent.
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Old 31-01-2014, 07:06 PM
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Camelopardalis (Dunk)
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Thanks Hugh - 15fps sounds pretty good compared to what I'm seeing but still, if you've got fast machines and still not seeing the magic 30 that's a bit of a worry.

Is that what's actually being saved into the output though? Maybe it's just something it's not updating correctly. I'll have to test again with a stop watch
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Old 01-02-2014, 10:44 AM
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pluto (Hugh)
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Just looking at a file now, the metadata says it's at 15fps and it's 33 seconds long. It should have captured 500 frames so a bit of maths says it's at 15.15fps.

I'll do a bit more testing in SharpCap soon.
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Old 01-02-2014, 04:59 PM
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Camelopardalis (Dunk)
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Interesting.

So I've tried changing the camera settings to 14-bit and then the video options switch to SER instead of AVI. It then merrily captures at 15fps, indicated. That's a way from 30 but it's an improvement...that and the camera sensitivity and increased resolution. Might stick it out in the garden later for some experimenting...
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