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Help with Firecap fps

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#1 Shinken

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Posted 24 July 2021 - 06:04 AM

Last night I was all setup to capture a transit of the ISS before the full moon.

 

2:24 AM and everything is good to go.

 

I am running an ASI183 mono from a scope-mounted headless miniPC. I use my laptop with Microsoft Remote Desktop to control/ the miniPC. The camera is plugged in directly into the PC's USB 3 port of the miniPC.

Fircap is reporting a capture fps of 18 occasionally dropping to 10. The recording fps is 6 or 7 . I immediately noticed that because of the recording lag I am dropping frames in the recording but not in the capturing. I keep going. I had previously played with USB rate from 40 to 100 and it appeared that 100 was the best based on capture fps. I also have ticked "High speed." On the screen I see the transit and I am so happy! I stop the capture. The recording finishes some 30 seconds behind. I noticed that I only recorded some 400 frames during the 3+ minutes of capture. Odd. When I get home and look at the video there are only 24 seconds recorded at reportedly 19 fps (which is the max for this camera) but there is no ISS. Just a nice full moon.frown.gif

 

The actual recording fps was 2. I missed the 1+ second transit even though everything else location, time, etc was right. Very frustrating.

 

Any one has some suggestions to maximize the recording fps with Firecap?



#2 Tom M

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Posted 24 July 2021 - 07:41 AM

I've seen similar using a BeeLink GK55 when doing solar but based on a lengthy email dialog with their support all of their mini PCs would behave the same. There are 2 separate issues it seems. First is that the main drive slows down significantly when over half full. The 2nd issue is that an internal SSD only runs at sata2 speeds even if a sata3 device. One way around this, assuming your mini PC has a USB-C port, is to use a USB-C -> SATA cable to an external sata3 SSD - though support did say this was never tested and is not supported. However it seems to work fine.

 

If you start up Windows Task Manager you can see the throughput to the drives and how it drops using the Performance tab. You can watch as Firecapture finishes the capture but the disk continues to write for several seconds. So it seems that Firecapture is doing its job but the data can't be written fast enough. Depending on how much internal memory you have you can increase the Heap size. None of this is an issue for DSO work but can impact anyone needing high capture rates for lucky imaging.


Edited by Tom M, 24 July 2021 - 08:07 AM.


#3 bobzeq25

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Posted 24 July 2021 - 07:44 AM

You might get better help on this one on the Solar System Imaging forum.



#4 Shinken

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Posted 24 July 2021 - 08:22 AM

Thank you Tom M and bobzeq25. So it looks like the issue is at the Beelink PC. As you have said I'm pretty happy with the performance for doing DSO imaging. The problem arises when doing fast captures. Can you suggest an alternative miniPC with better specs for this purpose?



#5 Tom M

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Posted 24 July 2021 - 10:04 AM

The simplest solution seems to be to use the USB-C -> SATA cable and an external SSD. Another choice is to limit the number of frames captured to avoid running into the situation with the throughput bottleneck.

 

A more costly solution is to get a mini PC with more memory so the heap size can be increased to allow the capture to be fully contained in memory. Other than that, you're pretty much looking at a standard laptop/PC.

 

As bobzeq25 suggested, you may want to post in the Solar Observing & Imaging forum as pretty much all of that capturing is based on lucky imaging.



#6 Shinken

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Posted 24 July 2021 - 12:35 PM

Thank you! I'll move to solar.




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