UDF is told to have replaced ISO for optical CD/DVD/BD discs. https://askanydifference.com/difference-between-udf-and-iso-with-table/ I wonder if someone can clarify if UDF version 2.5 or higher really is required for creating and burning Blu-ray video to VBD-discs. I've got this impression earlier, i.e for K3b here, which still seems to be much the case on Linux: https://bugs.kde.org/show_bug.cgi?id=257602 I've seen there could be UDF 2.5 on Ubuntu and possibly with tsMuxer(?) Bt in my case on Leap 15.4, and even on Tumbleweed, the latest available udf package versions are 2.1 and 2.3: S | Name | Type | Version | Arch | Repository ---+----------+-------+-----------------+--------+---------------- i+ | libudf0 | pakke | 2.1.0-1.27 | x86_64 | Main Repository i+ | udftools | pakke | 2.3-lp154.321.3 | x86_64 | 15.4 udftools 2.3 is even an experimental package from OBS with content /usr/bin/udfinfo /usr/bin/wrudf /usr/lib/udev/rules.d/80-pktsetup.rules /usr/sbin/mkfs.udf /usr/sbin/mkudffs /usr/sbin/pktcdvd-check /usr/sbin/pktsetup /usr/sbin/udflabel So what happends and decide the udf file system version when using mkudffs, bdwrite and dd or K3b lastly for burning? when I let K3b autodect the image (because there are no selection for UDF), it actually shows "ISO 9660" while burning. And the result has prooved to be playable Blu-ray discs in hw player.