VNP

frameData.getShort() returns a int16_t, signed. I think the culprit is somewhere over there

What do you mean by "the writer" -- the way you output these frames, either to the trimmed video and/or fits frames? Or sharpcap? AS4, PIPP etc read these files...

We've established the problem is also - in the frame debugger - in the img(nnn) output The same in AS4

IMHO, this symptom is definitely that of losing bits, it could well be the sign bit getting lost somewhere for whatever reason Your viewer is also a bit (one bit?)...

To better explain what I am talking about, please consider this naive snippet I quickly hacked togehter, where I make one bit get lost, because integer promotion etc moves the...

The trimmed video reflects this issue, but it begins earlier then the trimming. It is there from the very start, I have an idea, let me check it

OK, so you have two different methods to get the same color: One is here: https://github.com/melix/astro4j/blob/518c3ceb844991ec78b3cdb17cd7b6094c96d3f8/jsolex-core/src/main/java/me/champeau/a4j/jsolex/processing/ser/FastImageConverter.java#L91 And the other one is here https://github.com/melix/astro4j/blob/edac445e0eaa7257be6f15f50770f952db4e411a/jserfile/src/main/java/me/champeau/a4j/ser/SerFileReader.java#L223 Am I missing something?

Please look at not a few bits but a byte going missing, am I missing somehitng?

fucketyfuck, it was there in the log all along depth = 15 bits ``` 12:06:19.166 [INFO] Output directory set to D:\2025-07-08\Sun-3640_filter-n99--Skywatcher-OtaR62Ap400F-SHG 12:06:19.166 [INFO] File 2025-07-08-0847_0-Sun-3640.ser 12:06:19.230 [INFO] Date 2025-07-08T08:46:44.632850600 12:06:19.231...

Anyway, my intuition is that the sign bit, in some type inference, integer promotion, goes missing Another idea: why do you go var dataLen = width * height * numPlanes;...