.mp4 without transcoding
Obviously, don't do this unless you have a pressing reason. Matroska (
the better and free-er format and this only works if the video was in an .mp4
supporting format from the start (i.e. H.264 / H.265 with AC3 / AAC).
Requires mkvtoolnix (for
mkvextract) and gpac (for
Step 1 - Unbox the Matroska Container