Re: A Couple of Midi Tempo and TimeSig Questions
Re: A Couple of Midi Tempo and TimeSig Questions
- Subject: Re: A Couple of Midi Tempo and TimeSig Questions
- From: William Stewart <email@hidden>
- Date: Wed, 14 Apr 2004 11:18:53 -0700
On 14/04/2004, at 6:22 AM, Peter Zegelin wrote:
>
Hi,
>
>
When Core Audio builds its special Tempo track does it only look for
>
Tempo and TimeSignature events in track 1 of the Midi file? The reason
>
I ask is that I've only ever read that Tempo and TimeSig events are
>
*supposed* to be in track 1 but not that they *must* be in track 1.
>
For cross platform reasons I'm generating my own list of these events
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and want to make sure I'm doing the same thing as Core Audio.
Any tempo event in the file is added to the sequence.
>
Also is there any default maximum Tempo value? I'm generating a
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fairly standard squiggly line type Tempo view and was wondering what a
>
reasonable maximum might be. At the moment I am actually calculating
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the maximum tempo for the current file and using that, but is there
>
some sort of standard?
We actually have a bug with files that don't have a tempo event in
them... I'd generally consider these badly authored files, but it is
something we should have guarded against properly and didn't! The
default tempo that most people are using (including ourselves) is 120
bpm
>
Finally I have a slightly off topic question regarding TimeSignature
>
events. From my (limited) understanding of music theory, a time
>
signature must be for a whole measure i.e. you cant change time sigs
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in the middle of a measure. However, the way midi is set up it is
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actually possible to do this even though it would be incorrect. Is
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there some sort of standard on how midi players (or Core Audio) handle
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this situation? Do you just finish the measure when a new timesig
>
event arrives and start again from that point?
We don't do anything with the Time Sig (except preserver them of
course) - it doesn't have any affect on the playback of a MIDI file,
but rather on its presentation
Bill
>
>
thanks!
>
>
Peter
>
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