Encore - Swing playback

[Doug Kerr]

I said,

The algorithm I suggest (it may well be that what we have no is a broken version of this) would do essentially the following:

• Imagine a "face value" cell within which each note lives (ending at its current play duration).
• Apply the basic swing definition to the boundary between the cells, giving new "face value cells"
• In each cell, make the note duration the same fraction of the cell length that the pre-swing duration was of the face length (which was the "pre-swing "cell").

So if before the swing, the duration of note 1 was 80% of its face value, and the duration of note 2 was 90% of its face value, then after the swing the duration of note 1 will be 80% the length of its "adjusted cell" and the duration of note 2 would be 90% the duration of its "adjusted cell".

In fact, the current Encore algorithm does exactly this except that, for the second notes, if the initial duration of the second note was less than 100%, the duration of the second note (as adjusted) is greater than would be called for by the red clause in my algorithm.

The "error" is systematic, and I can probably characterize the "error" in the math. It seems to be an error in the algorithm calculating the length of the second note's "cell" based on the swing point (the so-called "amout of swing" parameter) for use in determining teh adjusted note's actual duration.

My guess is that Gvox's original plan was to use exactly the algorithm I now recommend, but that (for second notes, when the original duration of the second note is less than 100% of face), the calculation was (or is now) bungled.

Doug

[Denkster]

My guess is that Gvox's original plan was to use exactly the algorithm I now recommend, but that (for second notes, when the original duration of the second note is less than 100% of face), the calculation was (or is now) bungled.

I agree.

Maybe a concise bug report, with just this statement and a link to the post with the algorithm, directly to Matt, might trigger him to find and fix that bug?

kind regards
Eveline

[polarbreeze]

Encore does indeed understand the term "on the beat" and in fact it uses that concept when it makes decisions for the "beam on beat" function.

Beam on beat does not work as you apparently assume.
In a 4/4 measure, it does Beam-on-pulse, assuming two pulses in the 4/4 measure.

It seems to me that it follows standard beaming rules. You would agree that there's a difference between the "beam group" operation and the "beam on beat" operation? In order to do the latter, Encore needs to know where the beat is - and it does that correctly as far as I can see. It works as per the manual: "Beam on Beat uses the time signature and beat location for the selected notes to determine a default beaming combination".
.
It's my contention that the logic for determining how to pair notes for swinging is similar and probably identical.
.
As I said before, I don't think the term "pulse" has any technical meaning and in particular I'm not sure why you consider that a 4/4 measure has two pulses...?

[Denkster]

It seems to me that it follows standard beaming rules.

Describe your 'standard beaming rules'.
My 'standard beaming rules' for 4/4 measures are different of those Encore applies.

You would agree that there's a difference between the "beam group" operation and the "beam on beat" operation?

Yes.

In order to do the latter, Encore needs to know where the beat is

Yes.

- and it does that correctly as far as I can see.

I Disagree.

It works as per the manual: "Beam on Beat uses the time signature and beat location for the selected notes to determine a default beaming combination".

Apparently that sentence is ambiguous.

• uses the time signature and beat location - how?
• a default beaming combination - a = any? which default?

. It's my contention that the logic for determining how to pair notes for swinging is similar and probably identical.

I Disagree. Anyway, 'similar and probably identical' are totally useless terms in a design, no, worse: dangerous, misleading, a waste of time.

. As I said before, I don't think the term "pulse" has any technical meaning

You would be helpful if you could confirm this term is free then, to define as proposed: 'the beat(s) which have the emphasis'.

and in particular I'm not sure why you consider that a 4/4 measure has two pulses...?

I consider that a 4/4 measure can have two pulses, the first and the third, because these two often have considerably more emphasis then the second and fourth beat.

Eveline

[polarbreeze]

My 'standard beaming rules' for 4/4 measures are different of those Encore applies.

Could you please give an example of that?

'similar and probably identical' are totally useless terms in a design, no, worse: dangerous, misleading, a waste of time.

I was not trying to formulate a definition - just observing the potential similarity in the algorithms

You would be helpful if you could confirm this term is free then, to define as proposed: 'the beat(s) which have the emphasis'.

I don't think I'm the arbiter of that. But Wikipedia has a description of "pulse" too if that helps.

[q]

My guess is that Gvox's original plan was to use exactly the algorithm I now recommend, but that (for second notes, when the original duration of the second note is less than 100% of face), the calculation was (or is now) bungled.

I agree.

Maybe a concise bug report, with just this statement and a link to the post with the algorithm, directly to Matt, might trigger him to find and fix that bug?

Yes. A consolidated report may prove helpful and may help expedite a result.

q

[Doug Kerr]

Hi, q,

Yes. A consolidated report may prove helpful and may help expedite a result.

Done (in you-know-where).

Doug