There is a document called Vorbis Illuminated, which describes some of the Vorbis algorithm, but the last time I looked the section called "MDCT" was empty except for the title.
• Update 2020-10-16: Actually, that link is dead, and the domain name mathdogs.com has been usurped by dogfood marketing. For a few days I thought the whole project was dead, but it is still at xiph.org.
It was not a high priority, so I did other things for about a year. I got interested again, so I did a Google search for MDCT. I got just a few hits, one of which was my own mailing list question from a year previous.
I can almost hear you saying that you are tired of people whining about lack of documentatation, but this is not a complaint, it is an announcement that I did something about it. I searched the local library and the internet, came up with a few definitions, removed the errors and differing sign conventions and worked out the details.
This doesn't count as research; it is, of course "well known" in the mathematician's sense. Nevertheless, my experience leads me to believe that it is not perfectly trivial to actually become one of those who know.
This document is not complete, but I am releasing the draft because there is enough here that it may be useful to someone. Comments and suggestions for improvement are welcome, especially if you know the answers to any of the questions at the end.
May I suggest compressing the Postscript file, possibly with zip or gzip, to save bandwidth?All four of these are exactly the same contents, pick the one most convenient.Would it possible for you to make a PDF file of this document as well, for all us windows users?
Please do copy it, it saves my bandwidth. Also, PDF seems to be a de facto web standard, so that's it.