2 Questions Recreating film roll database and TIFF vs PNG for compressing it to HEIC

Software darktable
1

1 Recreating film roll database
I have a local SSD where I store all my raw and compressed Exported files as follows

/mnt/Data/A6300
under this there is date wise sub directories where I store RAW files like
/mnt/Data/A6300/2021-12-03
under this there is a sub directory darktable_exported where I store exported files like
/mnt/Data/A6300/2021-12-03/darktable_exported

I backup this A6300 directory with all its sub directories on an external HDD which when mounted is
/media/raj/BackupHDD/ and the A6300 directory is at
/media/raj/BackupHDD/A6300

If the SSD fails and I want to use the HDD with darktable till I install a new SSD how to recreate film roll? As of now it only allows to individual select an entry . Is there a way I can just change the base directory from /mnt/Data/ to /media/raj/BackupHDD/ to recreate film roll?

2. TIFF vs PNG for compressing it to HEIC

I want to compress my processed files to heic instead of jpegs and as darktable does not support it natively, should I export the file as PNG or TIFF to compress it to heic? The purpose is that the exported file should be as good as processed Raw to get a better compressed quality. Or any other suggestion?

2

Looks like there has been some work on it… just no mention of export…are the avif similar enough??

3

HEIC is a patent-encumbered format, and it is unlikely export will be implemented, so one could consider AVIF instead indeed.

YMMV might vary though, as one is still missing a couple of things when exporting to AVIFs from dt directly:

  1. XMP and IPTC metadata, there is only Exif
  2. Embedded thumbnail/preview
4

are you thinking of using 8 or 16-bit heic? i imagaine that tiff would be the best although probably no difference. why not test 5-10 imaages with both formats and see. As both are lossless (assuming you don’t use compression) then the only remaining factor is bit depth.

5

As far as I have read only import of heic is going to be supported so as of now I have been exporting either tiff or png and have a script which converts to 8 bit heic.

I never process any jpgs or heic in Darktable so that patch will not be of use to me.

Looking for a solution to my first question now.

6

Stick to jpeg then.

7

Or at the very least make sure there is a benefit in conversion to HEIC.

I managed to find one site which offered image extract for the two formats, and even there very little detail was provided about how the images were treated/converted. And what they showed for comparable file sizes didn’t convince me…

And if you really want to use HEIC, I don’t think there’s an advantage in using TIFF. Both support 16 bit/channel, and PNG tends to be a lot smaller than TIFF (at the same bit depth).

8

TIFF w/ deflate compression + horizontal predictor is very comparable to PNG. I would prefer it for better metadata support.

That being said, not all HEIC (nor AVIF or JXL) converters seem to support TIFF input…