[RTcmix-discuss] tb() negative values

Neil Thornock neilthornock at gmail.com
Mon Sep 12 16:43:15 EDT 2011

```You're right -- I'm not dealing with scaling tempos but rather with
very many (hundreds, maybe thousands) specifically indicated "notes"
(anathema to algorithmic music, I know...).  So a call to tb() would
only be relative to a certain point in time (the current start time of
the instrument), not my tempo at that moment.

Anyway, the solution was trivial; I perform the math operations
*first* and then make my call to tb().

This kind of rigamaroll is what I get for being only an occasional rtcmixer :(

Thanks John.  Say hi to the crowd for me.

On Mon, Sep 12, 2011 at 2:14 PM, John Gibson <johgibso at indiana.edu> wrote:
> Hi Neil,
>
> I don't think this works the way you hope it does. If you ask for tb(increment) where increment is, say .25, that gives you the start time of a 16th note at the very beginning of the tempo curve: it gives you the start time for the 2nd 16th in the first beat. That gives you an accurate duration for a 16th note anywhere in your sequence only if your tempo curve comprises one constant tempo. If your tempo curve has changing tempos, and you are playing a note in the middle of the sequence, this will not give you the right value. The beat values given to tb() are absolute, not relative. So a negative beat value doesn't make sense.
>
> J
>
>
>
> On Sep 12, 2011, at 3:15 PM, Neil Thornock <neilthornock at gmail.com> wrote:
>
>> Hi John,
>> Yes, this makes sense.  In my specific case, I'm using a starttime +
>> tb(increment) approach with a long score-type file.  Rather than go
>> through the pain of figuring out the start time at that moment, I'd
>> like to simply back up a few beats.  I can work around it with
>> conditionals but had hoped tb() could accept negative values.
>>
>> I see this in the source:
>>
>> 71 float
>> 72 time_beat(float timein)
>> 73 {
>> 74    int m = 0;
>> 75    float durp = 0;
>> 76
>> 77    if (timein < 0.0)
>> 78       timein = 0.0;
>>
>> Right there -- Is there any reason not to accept a negative timein
>> other than that we don't want a negative start time?
>>
>> On Mon, Sep 12, 2011 at 1:07 PM, John Gibson <johgibso at indiana.edu> wrote:
>>> Hi Neil,
>>>
>>> Can you give us a simple score that illustrates this?
>>>
>>> If your current start time is 10 beats and you want to back up by 4 beats, you would just use tb(6), no?
>>>
>>> In other words, the tempo mechanism is not aware of where you are in the beat series, beyond what you feed tb().
>>>
>>> J
>>>
>>> On Sep 12, 2011, at 2:48 PM, Neil Thornock <neilthornock at gmail.com> wrote:
>>>
>>>> Hi list,
>>>> I'm using tb() to scale my durations.  At one point, I'd like to back
>>>> up from the current start time by a certain number of beats, but it
>>>> appears tb() can't handle negative values.  Is that correct?
>>>>
>>>> --
>>>> Neil Thornock, D.M.
>>>> No Stopping, Standing, or Parking:
>>>> http://neilthornock.net/mp3s/nostopping.mp3
>>>> Assistant Professor of Music
>>>> Composition/Theory
>>>> Brigham Young University
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>>
>>
>>
>> --
>> Neil Thornock, D.M.
>> No Stopping, Standing, or Parking:
>> http://neilthornock.net/mp3s/nostopping.mp3
>> Assistant Professor of Music
>> Composition/Theory
>> Brigham Young University
>> _______________________________________________
>> RTcmix-discuss mailing list
>> RTcmix-discuss at music.columbia.edu
>> http://music.columbia.edu/mailman/listinfo/rtcmix-discuss
> _______________________________________________
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>

--
Neil Thornock, D.M.
No Stopping, Standing, or Parking:
http://neilthornock.net/mp3s/nostopping.mp3
Assistant Professor of Music
Composition/Theory
Brigham Young University
```