I have been looking for a suitable self-contained live stacking program that is easy to plug in. The criteria that I used are:

1) Stack from a folder. This is useful for cases when you don't have a camera hooked up and want to be as independent as possible from the embedded target (so long as you can export a folder to the host).
2) Decent and easy to use graphics to stretch the stacked image.
3) Speed, responsive.
4) Retain stretching parameters when a new sub comes in. Of course, this only matters with decent graphics.
5) Free.
6) Cross-platform. It's nice if you can run it on host and target. However, it may be better to run it on a host to not affect the real-time target behavior.
7) Scriptable (to customize preprocessing and stretching features).

I scored ASTAP, Siril, DSS Live, AstroToaster, ASIStudio, StellarMate and SharpCap on these criteria but won't present a table here - I would have to double-check for liability reasons.
The hardest criteria turned out to be the combination of (2,4) because I found only one suitable candidate suitable, maybe two (one that I have not tried myself but that I heard was good). Without it, it's worthless regardless of how much effort was put into the rest.

Just some usability criteria from a user's point of view, HTH.

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