using marzipano tool without downgrading 360 photo resolution?

[Alex _]

Hello,

I used https://www.marzipano.net/tool/ to make a virtual visit of a 170m2 house with my insta360 One X. It made 27 photos, for a total of 190MBytes (approx 7MB per photo).
However, the resulting marzipano directory (once the zip is extracted is about 70Mbytes).
=> there must be some sort of compression being done by marzipano.

And the resolution in resulting marzipano zip files once observed in the browser VS the observed 360 image BEFORE I drag and drop it in marzipano tool is noticeably/visually different.
original = 6080x3040x24
in marzipano = I have not clue ! 🤨

I used the default https://www.marzipano.net/tool/ (as of May 20th 2024)

I tried looking into the UI, the documentation, the references, and except for the tile dimensions (defaults to 512... but the size of one tile could potentially say nothing about the resolution downgrade) => I did not find anything.

Anyone can point me in the right direction? I suspect this is about the code that get exercized upon a drag&drop of an image. but I don't really know where to start.

thanks
alex

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one detail of one original photo (on the fridge). opened in vlc, zoom max, then screenshot copy/paste here

screenshot of the same detail from the finished tour 

I have the same observation when I open the photos in google photos vs chrome/marzipano tour