MMC play reverse


I am trying to do a transport with a reverse play command at speed -1:1 for pro tools.

I am using the shuttle (47) MMC command but without sucess so far.

I found some info in the midi specification that led me to this command : F0 7F 7F 06 47 03 (sh sm sl?) F7

But i am confuse about standard speed in the midi specification especially the sh sm sl variable and how i can translate these values in HEX.

I am not even sure if it is possible but pro tools have a shuttle mode.(It works with when i trigger the keystroke ctrl 5 -)

Can someone help me out?


Well I'm not sure if Pro Tools supports MMC reverse shuttle but if it does, it should look something like this


F0 7F 7F 06 47 03 41 0c 66 F7

The high order bit of in 41 is the reverse flag. The low order bit (1) is seconds.  the remaining 0c 66  represents 1638/16384 of a second or roughly 1/10th of a second.

I've attached a diagram from the spec that shows the bit mapping.

Steve Caldwell
Bome Q and A Moderator and
Independent Bome Consultant/Specialist