Bug Report: Altair cameras 183m and 26m

[jonchard]

Using both Sharpcap 4.0 and 4.1 i can reproduce the following issue.

I start a sequence with exposure 1ms, 8 bit, roi at 320x200 to give fastest framerates. Frames peaks to about 208 on both cameras on both version of sharpcap. Suddenly around 900 frames in fps dropto to around 10fps for a good few seconds, camera appears to re-initialise and FPS suddenly jumps to 208 fps once more ... runs for a while then drops to 10fps rinse and repeat.

It would appear to be acting like its caching to disk, but all disks write at 400mb/s so not slow disks. THe one give away is that the 183m has its fan running. A moment before the fps jumps back up to 208fps, the cameras fan resets! Hence why im stating that the camera appears to reinitialise then we have an instant fps jump.

The fan does not reset on 26m camera but the behaviour is IDENTICAL. Both sharpcap 4.0 and 4.1 behave the same. It also behaves the same between two completely different laptops with different disks. SImilar amount of time to FPS drop .. same reinitialise of fan on 183m.

Altairs Capture program does not exhibit this behaviour.

Jon.

[admin]

Hi Jon,

the fan pause is a giveaway that the camera has stopped sending frames and SharpCap then resets the camera to get it going again. I can see a similar problem in my testing, but have to set an even smaller ROI (96x96) to make it happen at all regularly.

In SharpCap I can work around it by turning the USB speed value down (rarely happens at speed 2, never at speed 1), but that doesn't seem to be necessary in AltairCapture, so I will have to investigate to see if I can work out the cause - I suspect not responding to the camera's "frame ready" notification quickly enough.

Hopefully the USB speed trick will give you a workaround for now, thanks for reporting.

Robin

[jonchard]

Well done Robin, thank you so much for taking it on. I also saw similar in that it happened less often with lower USB, but of course we all strive for absolute maximum FPS! I will work that until you find a fix. I appreciate it must be bottom of the pile but of course always happens when our largest pile of cameras happens to be Altair! Again, thank you for your attention, and good luck in finding it!

[admin]

Hi Jon,

actually I found the cause for this and have a fix which should be in the next update of SharpCap 4.1 - hopefully later today. It only shows up when the frame rate is very high and in that case sometimes the flag for 'new frame ready' was being cleared after it had already been set.

cheers,

Robin

[jonchard]

Amazing Robin! Robin ... Stand up! *Claps all around* Well played that man!

Im truly grateful.