Re: [LAU] multitrack export midi type 0 (gramophone2) issue

On Sat, 20 Feb 2016 19:08:03 +0000, Rui Nuno Capela wrote:
>On 02/20/2016 06:15 PM, Ralf Mardorf wrote:
>> On Sat, 20 Feb 2016 17:52:20 +0000, Rui Nuno Capela wrote:
>>> now about tracks with different speeds (tempo?, tpqn/ppqn?) is a
>>> complete another story: the MIDI file standard just doesn't allow
>>> for different tracks/channels with different speeds whatsoever.
>>> where did you get the idea?
>>
>> At least some professional, if not all professional sequencers allow
>> to lock tracks at the current used BPM, then it's possible to give
>> other tracks different BPM. This isn't just needed for freakish
>> polyrhythms, it's a must to sync special effect sounds to film by
>> SMPTE and still to be able to change the BPM for some ambient effect
>> sounds/music. IIUC this is what's the OP produced and wishes to
>> export and import. This might not be provided by a single file
>> standard, but the OP wants to split a file into it's tracks and than
>> import it to a sequencer that allows to use different tempi.
>>
>
>some smart sequencer might but i repeat and assure you that the SMF
>format 0 doesn't.

Not the different tempi as a format information, but an exporting
sequencer could render the note positions for the different tracks in
relation to one BPM information.

MIDI track 1 recorded a laser gun shot at 120 BPM at the beginning of
bar 2, so the event is at 2 seconds. Without locking the track and
changing the speed to 90 BPM the same bar position would be at 2.666
seconds. If you lock the track at 120 BPM, before you change the speed
to 90 BPM, the event stays a 2 seconds, but the new position would be
at bar 1.4.

To lock a track at a special BPM setting doesn't mean it does use this
BPM, it means that the sequencer keeps the absolut time position, but
calculates new bar positions in relation to the used BPM, when changing
the BPM.

So if you sync a film, the sound effect of the laser gun always stays
at 2 seconds, the time when the human shoots the Martian or vice versa,
but you still can change the tempo of the background music.

A smart sequencer might even be able to show tracks with different
BPMs, but under the hood it's a calculation in relation to one BPM.
_______________________________________________
Linux-audio-user mailing list
Linux-audio-user@email-addr-hidden
http://lists.linuxaudio.org/listinfo/linux-audio-user
Received on Sun Feb 21 00:15:01 2016