Quicktime pitch bend range

HI Paul and Monz

I've just done a bit of quick time programming to add
QT support to FTS and have found out more about the
pitch bends in QT by having to send them myself.

What it is is that internally they use signed 16 bit
integers for pitch bends instead
of the unsigned 14 bit ones usual in Midi.
(14 bits because one bit in each byte is used
to distinguish between data and status bytes)

So the pitch bend step is indeed 8 bits per
semitone i.e. 256 - internally anyway.

That might also explain the +-2 octave range -
because if 8 bits is for one semitone then with
the usual 7 bit pitch bend numbers, that
leaves another 6 bits for the number of semitones
and 2^6 = 64 So one can manage +-two octaves
as that only needs a range of 0 to 48, while
+- three octaves requires 0 to 72 which is too much.

At least that's one possible explanation.

So Monz's page is indeed correct, and the
documentation is a bit confusing if you think
of it in terms of the usual 14 bit semitones.

Possibly by 7 bit there they mean 7 bits + a sign
bit?? Because really it's twice 8 bits internally, which is why
it can be 256 notes to an octave.

Not sure I totally understand the documentation
yet but it is a bit clearer anyway and hope
this helps. Sorry to have confused anyone
about it.

Robert