It's actually an ADM BWF, but mixed only using the 7.1.2 'bed' channels (no objects).
View attachment 96966
Yes, I decoded the spatial.MP4 (Atmos DD+) with MMH, and I only get the same result as the Atmos.wav file only when using 7.1.2 channels layout.
It caught my attention how the DOC file explains in a weird way the different file formats:
Atmos.wav - Full Dolby Atmos Mix for listening on Dolby Atmos system
What is Full? For me that is not Dolby Atmos, in a final coded consumer format. It is the 'decoded' Atmos mix for the 7.1.2 bed channels.
What systems can play in "Dolby Atmos" a 10 channel WAV?
BIN. wav - Binaural mix- for enhanced 3D headphone listening on any device
OK. That seems right.
Spatial .mp4 - Simulated Dolby Atos mix – for listening to (in stereo) on any Apple device. As heard when streaming on Apple Music with headphones.
"Simulated"? This is authentic Dolby Atmos encoded in DD+ This should be the file format for listening on a Dolby Atmos system, (not the Interleaved mch WAV), but it suggest that this would only be used to 'downmix' and virtualize to stereo from streaming (only Apple?) on headphones.