I have same problem. Recording with ASI1600 ROI in 16 bit mode result in just bunch of noise. Also the timestamps are all over the place like year 10000 and such. I am using ser-player to play back recorded files. But with some ROI sizes it seems like it can record properly. Like 500x500 it is recording fine but tanything smaller result in noise. Also I am not entirely sure but there may be difference where I set image size if in Image tab or Streaming tab of control panel. Also when I set 300x300 pixels it change it to 296x300

Last time I tried it was ASI071MC Pro.
-- 16 bit. It records but frames look weird. As if they were grossly overexposed.
-- 8 bit. OK.
-- 8 bit. ROI. Noise. But I haven't tried square ROI. ROI was selected in Live View window.

Will experiment more tonight.
Thanks!

OK. Did some experimenting.
SM 1.5.4 (recent but not one of the latest betas with the new internal solver). RPI4 4Gb. ASI294MC Pro.

SER files were acquired on RPI. Single frames were extracted on Windows 10 PC with SER Player.
Frames resized to 25%.
Exposure time and gain were the same for all recordings.

Summary:
16 bit doesn't work properly. SER recordings look bad but individual captures and Live Video looked fine!
8 bit works except for cropping in Live Video.

16 bit full frame:


16 bit cropped in Live Video window:


16 bit cropped in Capture settings:


8 bit full frame:


8 bit cropped in Live Video window:


8 bit cropped in Capture settings:

So I can confirm that 16bit look "bad", but I'm not sure what's causing this. Byte swapping required?

I have no idea why but two things are not right:
-- 16 bit and
-- ROI selection in Live Video for both 8 and 16bit.

8 bit is fine except for ROI in Live Video.

Thanks!

Thanks for the update, I'll take a closer look at this after 3.5.0 is released.

Thank you, Jasem!
I am not into planetary imaging much but upcoming Jupiter/Saturn collision (and earlier Mars opposition) got me interested.
I tried some 3rd party solutions, such as oaCapture etc., but they interfere with Ekos making them hard to use. I would like to stay in Ekos ecosphere as much as possible.
With 8 bit, Ekos works for planetary. It's a bit awkward to define an ROI but doable.
Thanks for your hard work!

I contacted SER Player author and he told me Endianess is not really respected as far as the actual astro-processing software go. At any rate, I put it now to always use BIG_ENDIAN and the results appear to be correct. Please use latest INDI and re-test.

Jasem - thank you very much for looking into this!

I wish I could test but I only have access to official updates (and Windows KStars nightlies) .

Jasem -
After I updated to 1.5.5 everything seems to be working!
Thank you so much!

Just captured Mars in 16bit. Live Video, 200x200 ROI selected, SER file. ASI071MC.
Mars is so small now (compared to October).

Most of the credit really goes to Pawel Soja, he's done an outstanding work improving the streaming & recording performance in INDI.

Pawel Soja - thank you very much!