1.9.5 JPEG-li and Estimated quality

[vovka]

potentially dangerous behavior of 'Estimated quality'
for example:
i have a PNG file and i want to save it as JPEG
i select 'Save as' and in 'Options' I check 'Use JPEG-li' and set 'Quality' to 90
now I have a 185KB file, and 'Info' pane shows that 'Estimated quality' is only 57 (which is baffling)
i close the file
i reopen it
now I select 'Save as' and in 'Options' I uncheck 'Use JPEG-li' and check 'Use estimated quality'
now I have a 114KB file and 'Info' pane shows that 'Estimated quality' is also 57
but the quality of the file is now much worse because '57 quality of JPEG' and '57 quality of JPEG-li' are quite different qualities

i think XnView must somehow distinguish the files by their compression codecs and recalculate 'Estimated quality' accordingly
so that we do not accidentally downgrade our images

[xnview]

i have no way to check that a jpeg file was compressed in JPEG-li

[vovka]

i have no way to check that a jpeg file was compressed in JPEG-li

thank you for the answer
i've noticed that ExifTools shows a different value for JPEG-li files
or it is not a reliable marker?

[meteorquake]

I would imagine you might need a custom tag that records the relevant xnview save info with maybe an option to do so. But I'm not sure how many people would need it. Other than that, it's probably good to always know exactly how you're saving things.

* It would perhaps be easier for xnview to generically assess when save quality is likely to be substandard and issue a warning (either a popup on save which could be disabled in settings, or just some written warning in red when saving).

* I do think XNView would benefit from a preferred set of options per format (jpegli separate from jpeg) and the save dialog summarises which options deviate so you can be alerted to click Options and adjust. This could be achieved by having "Save Default"/"Load Default" available against the settings (e.g. the Save dialog options or under Settings - Write). So for example if you normally have save quality 85 and last saved as 60, when you save it and subsequent ones it would show the summary "Quality 60" in line with the Options button, until you've changed it back to 85.