Stumbled over this. No idea what it is or who the composer is or anything. Some of the music is very good. It has that open orchestral old school writing (and recording) that characterised late 70s and early 80s soundtracks like Secret of NIHM, Heavy Metal and some Brian May scores.
The musicianship is of a VERY high order indeed, and it's obviously a major concert event.
It's extremely long (haven't watched all of it), and quite lot of it is not my cup of tea (a bit schmaltzy sometimes). But here are a few moments I skipped to and found admirable:
The composer is the one and only incredible Joe Hisaishi performing his film score works. I haven't looked through the entire video yet, but those opening film clips are from Nausicaä of the Valley of the Wind (1984) -- a good film in its own right and worth checking out.