You should have a look at
these converters.
Those only convert sample data though. You need to split them separately afterwards.
You can run the tools on either the ROMs from the ROM set that contain the sample data or on
uncompressed VGMs. (rename .vgz to .vgm.gz and use 7z or WinRAR to decompress them)
My post in that topic also has a few details on how to extract samples from VGMs using a hex-editor. Extracting samples from the VGMs first and running the decompression tools on those extracted samples may reduce DC offsets.