I have more information now.
I built on a 4GB RPi4 using the standard raspbian 32-bit OS and ran essentially the same tests that I ran yesterday on the 64-bit OS build using a ASI6200MC camera.
Firstly, the auto-stretching automatically happening when adaptive sampling is turned on did NOT occur (as it had yesterday on the 64-bit OS). So either that was fixed or I hallucinated it yesterday.
In any event, I ran a sequence of 20 Bias image captures with debayering turned on, adaptive sampling turned on and auto-stretch turned on. I got the message about not being able to allocate the debayering buffer while processing the 9th image in the sequence, after which kstars crashed. Note: the memory monitor says the system has 3.32GB available and the monitor never showed resource use exceeding 2GB, but of course there could have been a spike that did not register prior to the crash.
Next I ran another 20 bias image sequence with debayering turned off, limited resource turned on, adaptive sampling turned on and auto-stretch turned on. The entire 20 sequence completed successfully.
Next I ran another 20 bias image sequence with debayering turned off, limited resource turned on, adaptive sampling turned OFF and auto-stretch turned on. KStars crashed after about 3 images.
So, what I get out of this is the following:
- adaptive sampling allows kstars to handle large sensor cameras WITH NO debayering on a 32-bit OS 4GB RPi4.
- with or WITHOUT adaptive sampling, kstars can handle large sensor cameras WITH debayering on a 64-bit OS 8GB RPi4.
So, for large sensor camera, adaptive sampling is needed improvement, but it is not sufficient to allow debayered images. Running KStars on a 64-bit OS RPi4, however, is a better option, if available, as it also allows debayering.
So, this goes back to my plaintive query at the end of my previous post: does anyone know how to control the overall "magnification" of an app on RPi4. As I mentioned, when I run kstars on the 64-bit OS, it appears as if it were magnified and so has ridiculously large windows that don't always fit within the allotted screen size. Other applications (terminal, web browser) don't exhibit that magnification. So, if anyone knows how to control that in one of the application start-up files, please, please tell me!!