about VTS_01_0.BUP issue on DL DVD, we have received the support request. This is related to CopyToDVD V3, the issue will no longer be here with copytodvd 4. At least, we will re-check that carefully.
About DL iso being reproduced correctly, here is how CopyToDVD handle the layer break:
If a filesystem is provided (not from ISO), the layer break is 100% decided by CopyTo, which is able to relocate and move the files to set the best possible layer break.
If ISO image is provided, CopyTo read the UDF filesystem inside the ISO image, check the DVD structure and find the layer break by examining the IFO files inside the ISO. However, CopyTo cannot relocate the files inside an already built ISO image, so the choice of the layer break is more restrictive and might be not optimal. If such occur, a warning is issued in the log.
If a MDS file is present with the ISO file, it is ignored by CopyTo. However, as far as we have tested, Copyto V4 always find the same layer break as the one stored in MDS.
The layer break determination (especially in ISO files) has been improved , so in V4, it’ll work better than in CopyTo V3.