MakeMKV cannot scan some discs created by Pioneer DVR-545HX-S

[sba923]

To save space on shelves, I’m ripping discs containing material I recorded from TV broadcast channels using my Pioneer DVR-545HX-S recorder… eons ago .

Some of those discs can’t be read by MakeMKV (the “scanning” phase runs for a while… and then stops) – my DVD drive is an LG HL-DT-ST DVDRAM GH22NS50; I’ve tried with a Pioneer external USB3 Blu-Ray burner, same issue).

I can’t play them using VLC. Also scans for a while, then fails with an error message.

If I extract an ISO image from the disc using IsoBuster, and then feed the ISO file to MakeMKV, it works.

Any clue?

If you want an example of an ISO image for such a disc, and for another disc made by the same Pioneer device but that MakeMKV has no problem with, check out https://1drv.ms/f/s!AjBPRo9wXw9s-60TYlR ... Q?e=wXSG8h. I've also included a video of what MakeMKV does with such a disc.