The MIDI Forum

  Thursday, 22 December 2022
  2 Replies
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On page 12 of the MIDI CI Spec v1.1 it says:
Broadcast MUID = 0x0FFFFFFF

However in the discovery message, invalidate muid, profile enabled report and profile disabled report messages it shows:
7F 7F 7F 7F - Destination MUID (LSB first) (to Broadcast MUID)

I would think that this might just be an oversight, but it is hard to tell if the broadcast bytes are limited to 7 bits or not?

I think we will need some clarification in order to ensure this is standardized.

One other thing that might make the process of developing for MIDI2.0 would be to have some pre-defined test conditions with bytestreams, and the pre-defined interpretations. I am synthesizing these bytestreams by hand currently, and will be posting a large number of example byetstreams soon. It would be good to check against whatever reference encoded messages that the MIDI Association is using.
tenkai set the type of the post as  Admin Post — 1 month ago
1 month ago
MIDI-CI messages are transmitted as Universal System Exclusive messages. (In the MIDI-CI spec, see printed page 16 / PDF page 21 "Standard Format for MIDI-CI Messages".) All the data bytes in a System Exclusive message have the most significant bit clear.

As explained in a previous thread (Question after reading the MIDI-CI 1.1 Spec RE: MUIDs), FFFFFFF and 7F 7F 7F 7F are two different representations of the same 28-bit value (28 one bits):

FFFFFFF represents the value in the continuous range from 0 to FFFFFFF.
7F 7F 7F 7F is how the value is encoded into four System Exclusive data bytes.
1 month ago
Ah, yes I see. It is basically 8 bit messages, spread over the 7 usable bits of each midi byte, resulting in a 32 bit bytestream from a 28 bit message.

Thank you for the clarification!
Clemens Ladisch set the type of the post as  Technical Question — 1 month ago
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