MP4 is not described by single type. You call it MP4, but inside many things can be different.
Read reply form ffmpeg developers. It explains when TWOS is allowed, which seams to be aligned with
http://www.mp4ra.org/codecs.html.
"ISO 15444-3 - the specification that allows raw audio - defines that such files have the brand mjp2 (which is currently not supported by FFmpeg for output files) and not mp42. I wonder how Sony explains the creation of such files.
In order for MP4 to store TWOS as per spec brand (I assume type of MP4) has to be mjp2, which is not the case for Panasonic nor Sony files.
If you like wiki (
https://en.wikipedia.org/wiki/ISO_base_ ... ile_format):
"The JPEG 2000 specification (ISO/IEC 15444-3) defined usage of Motion JPEG 2000 video compression and uncompressed audio (PCM) in ISO base media file format (.mj2)."
which for me sounds like: using TWOS=specific case.
In other words- TWOS is described in (ISO/IEC 15444-3), so in order to use it MP4 brand has to be mjp2, not a more common mp42. This is how I understand it, but I may be wrong.