OK sorry, you wrote mds, I thought it’s an md5 file, ignore my post
“A [disc image] may be accompanied by a Media Descriptor Sidecar file. This optional binary file (with file extension .mds) contains metadata about an imaged optical disc, including a delineation of where disc layers begin and end (“layer breaks”), and which portions of the [disc image] belong in which disc layer.”
Also, I highly recommend using ImgBurn to burn discs. Best burning software ever anywhere, and it’s free.