When I first saw this Pronto hex sequence I thought it was a fragment because it is 2-bits but there is a ccf file
[Link: remotecentral.com] that has the identical command for "Standby"
Interestingly, every other commmand in that file is NEC2 Device 8 (that is 32 bits). So I can't see any logical way to derive the Discrete ON/Off commands other that to try all 256 NEC2 Device 8 and even then it looks like they treat the Power Toggle command very differently.
In the interim, many DVD's respond when Off to the Play command. So Play/Stop=ON, Play/Power Toggle=OFF.
If you really want to try all the device 8 commands, I can explain how to do that.
HTH,
Jon