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Luppp's internals use a single(!) floating point, which mixes a bar number,

and a "percent" of that bar.

Found it quite nice to work with, to get the bar you just:

int bar = (int) floatBeatPercent;

while to get the percent you:

float percent = floatBeatPercent - ((int)floatBeatPercent);
In C you mention "bar" as int, and "beat" as float, I presume you want to

use the decimal part of the float to show "progress" trough that beat?

Thinking about very slow BPM's.. that could become important.
-Harry
On Tue, Feb 7, 2012 at 12:28 AM, David Robillard  wrote:
> Hi all, seeking opinions:

quoted text
>

> I have to choose a way to represent beat-based tempo time in 64 bits.

> Uses are many, but the main one is event time stamps for plugins.

>

> Requirements:

>  * No odd data sizes (for performance / programmer ease)

>  * High precision (ideally close to sample accurate for most tempos)

>  * Fits in the same space as two uint32_t's

>

> Questions:

>  * Is "bar" needed?

>  * Use floating point?  Rounding errors an issue?

>

> Options:

>

> /* A (moderate range, ultra precise) */

> struct {

>    uint16_t bar;

>    uint16_t beat;

>    uint32_t tick;

> };

>

> /* B (high range, moderate precision) */

> struct {

>    uint32_t bar;

>    uint16_t beat;

>    uint16_t tick;

> };

>

> /* C (high range, good precision?) */

> struct {

>    uint32_t bar

>    float    beat;

> };

>

> /* D (high range/precision, but no bar) */

> double beat;

>

> I havn't run the math on precision yet, but I am leaning towards C.  I

> actually hadn't considered mixing int and float before writing this

> email, but it seems the best trade-off, and working with float is

> certainly more pleasant than fixed point.

>

> Thoughts?

>

> -dr

>

>

> _______________________________________________

> Linux-audio-dev mailing list

> Linux-audio-dev@lists.linuxaudio.org

> http://lists.linuxaudio.org/listinfo/linux-audio-dev

>

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Luppp's internals use a single(!) floating point, which mixes a bar num=

ber, and a "percent" of that bar.Found it quite nice to work =

with, to get the bar you just:int bar =3D (int) floatBeatPercent;wh=

ile to get the percent you:

float percent =3D floatBeatPercent - ((int)floatBeatPercent);In C y=

ou mention "bar" as int, and "beat" as float, I presume=

 you want to use the decimal part of the float to show "progress"=

 trough that beat? Thinking about very slow BPM's.. that could become i=

mportant.

-HarryOn Tue, Feb 7, 2012 at 12:28 A=

M, David Robillard <=

d@drobilla.net> wrote:

Hi all, seeking opinions:
I have to choose a way to represent beat-based tempo time in 64 bits.

Uses are many, but the main one is event time stamps for plugins.
Requirements:

=A0* No odd data sizes (for performance / programmer ease)

=A0* High precision (ideally close to sample accurate for most tempos)

=A0* Fits in the same space as two uint32_t's
Questions:

=A0* Is "bar" needed?

=A0* Use floating point? =A0Rounding errors an issue?
Options:
/* A (moderate range, ultra precise) */

struct {

 =A0 =A0uint16_t bar;

 =A0 =A0uint16_t beat;

 =A0 =A0uint32_t tick;

};
/* B (high range, moderate precision) */

struct {

 =A0 =A0uint32_t bar;

 =A0 =A0uint16_t beat;

 =A0 =A0uint16_t tick;

};
/* C (high range, good precision?) */

struct {

 =A0 =A0uint32_t bar

 =A0 =A0float =A0 =A0beat;

};
/* D (high range/precision, but no bar) */

double beat;
I havn't run the math on precision yet, but I am leaning towards C. =A0=

I

actually hadn't considered mixing int and float before writing this

email, but it seems the best trade-off, and working with float is

certainly more pleasant than fixed point.
Thoughts?
-dr
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Linux-audio-dev@lis=

ts.linuxaudio.org

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