I have authored DVD. Can SRT create a DLT master from my files?

Absolutely, in fact we would recommend you do this, for the reasons mentioned above. If you send us a master on recordable DVD, we always prefer to copy it to DLT and make you a new test copy. In the process, to reassure you that there are no "hidden suprises" waiting when the disc goes on sale, we perform a bank of tests, including checking the disc with a DVD Specification verifier.