How to defeat the bottleneck?
Posted: Sat Dec 21, 2019 11:47 am
I am using the ZWO ASI183MM for lunar imaging. At 20.18 megapixels, I know I'm pulling a lot of data. Typically through the first 1,000 frames captured, I'm averaging around 17 fps and zero dropped frames (good speed for this camera). As I inch past 1,100 frames captured, I start dropping frames. By 1,300 frames captured, I'm down to 3.2 fps and dropping a lot of frames. I've increased buffer to 7,102 Mb. I'm using an SSD drive and I have 16 GB RAM on a Windows 10 laptop and USB3.0. My speed test (within SharpCap) reads 475.972 Mb/s, 4,882 frames (1280X960) written in 12.02 seconds.
When I reduce the ROI to something more typical of a planetary camera (say 1280X720), I don't drop frames at all, no matter how many I capture. I suspect there is a bottleneck somewhere. Does anyone have any idea where that might be? Perhaps it is a clue that it only begins dropping frames after a certain number of frames are captured. I should note that as the hard drive begins to fill up, it appears that I start dropping frames earlier in the sequence; however, I am very uncertain about this. I've only used the camera a few times and this could be perception based on anxiety ("Arghhh...I'm running out of space!") rather an observation based in reality.
Short of buying a new laptop, I can add more RAM or a larger SSD (just ordered one). Let me know any ideas you might have. This is a great camera - I'd like to unlock its full potential.
George
When I reduce the ROI to something more typical of a planetary camera (say 1280X720), I don't drop frames at all, no matter how many I capture. I suspect there is a bottleneck somewhere. Does anyone have any idea where that might be? Perhaps it is a clue that it only begins dropping frames after a certain number of frames are captured. I should note that as the hard drive begins to fill up, it appears that I start dropping frames earlier in the sequence; however, I am very uncertain about this. I've only used the camera a few times and this could be perception based on anxiety ("Arghhh...I'm running out of space!") rather an observation based in reality.
Short of buying a new laptop, I can add more RAM or a larger SSD (just ordered one). Let me know any ideas you might have. This is a great camera - I'd like to unlock its full potential.
George