I understand the problem is resolved, but in case Geoff or anyone else is curious about Sequencer Specific meta events...
A Sequencer Specific meta event is a similar concept to a System Exclusive message:
The contents of either a System Exclusive message or a Sequencer Specific meta event begin with a 1-byte (or if the first byte is zero, a 3-byte)
Manufacturer ID. The contents after the Manufacturer ID are defined by that manufacturer.
A System Exclusive message is sent to the MIDI output device. A Sequencer Specific meta event (like all meta events in a MIDI file) is only visible to the software that reads the MIDI file, it doesn't send anything to the MIDI output device.
According to the
Anvil Studio User's Guide, "Anvil Studio stores Sequencer-Specific MIDI events to remember things like links to audio files and some staff note properties."
(Looking at the
example MIDI files on the Anvil Studio website and Tadej's example MIDI file in this thread, it appears Anvil Studio's Sequencer Specific meta events' contents always begin with hex 05 0F. However, hex 05 is the Manufacturer ID for Passport Designs. I don't know if this means Anvil Studio uses the same format of Sequencer Specific meta events that some Passport Designs software uses.)