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**Trenavix** · (This post was last modified: 04-07-2018, 07:03 PM by Trenavix.)

In SM64, each sound has some parameters attached to it.
Some of these parameters are labelled "ADSR" under the sound tool.
More information on ADSR parameters are discussed in this thread.
Furthermore, there are parameters for base keys and instrument looping. Here, I'll discuss everything I know about the subject.
In most games, base key is given by a byte (0-127 or 0x00-0x7F) with a de-tune byte alongside.
In SM64, the base key is given by a float, in which one can assign a fractional key without using de-tune.
The following formula converts key to float:

Code:
Float = 2^((60-key)/12)

Here is a graph of the function:

[Image: SM64KeyToFloat.png]

And here is an entire table of floats for each key:

So, if you wanted a 72-and-a-half key (mid-semitone), you would use 2^((60-72.5)/12) = 0.485766.

Now, there are optional previous and secondary samples for instruments. Using the "splits/release" value in the sound tool, you can choose the ranges for the primary sample before it splits to the previous or secondary sample (min/max keys before switch).

The value goes something like:

Code:
[00] [Min Key +- 0x15] [Max Key +- 0x15] [Release Time]

Where each value is a byte. I'm not sure why 0x15 is added or subtracted from each, but it's consistent, as in for 3 samples, it'll always be subtracted, and for previous-primary, it's always added. (More testing needed)

For instrument looping, having count set to 0x00000000 will DISABLE looping.
Having count set to 0xFFFFFFFF will ENABLE looping.
Loop start and end is used in cycles as measurement, in hex of course.
So having a larger value for end will wait longer for the loop.
Let me know if you discover any more information on sound data!
(Credit to shygoo for figuring out the float from key formula given correlated data)

**Trenavix**

Figured out sample loop units: Samples.
So if your sample is 3.12 seconds long at 32KHz, you would calculate it as:
3.12 * 32,000 = 99,840 (0x18600)
So the end of your sample in the sound tool should be 00018600!

**PablosCorner** · (This post was last modified: 05-15-2021, 03:37 AM by PablosCorner.)

I'm gonna add on to this, as I was experimenting with how the splits for the primary/previous/secondaries worked. And I was able to come up with this.

Quote:For samples that use Primary + Previous, you subtract 0x15.
For samples that use Primary + Previous + Secondary, you subtract 0x15.
For samples that use Primary + Secondary, you add 0x15.

I initially thought you had to add 0x15 to Primary + Previous, however that led to results that weren't accurate to how I wanted it laid out, but when I subtracted it, it worked perfectly. Turns out that it's Primary + Secondary you need to add 0x15 to.

**nutta** · 06-05-2019, 03:01 PM

Another thing to add;
The difference between both sample rates 32000 and 22050 and converting between samples.
A sample with the pitch C in 22050 would be G in 32000, which would make sense it's 7 semitones apart(perfect 5th) and a common interval in music structure.

**PablosCorner** · 07-13-2021, 06:26 AM

May as well post this here, as this is Nutta's thread on the ADSR value, but it's now properly archived since it's on Skelux's old site, which who knows what will happen to it in the far future.

The ADSR Thread - Nutta (Archived)

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