ok so i'm not exactly sure how to describe this problem as i'm new to Audio analysis as a whole so i'm going to explain it step by step.

1. So i have this algorithm here written in csharp

// Put into groups
for (int i = 0; i < onsets.Count-1; i  ){
    for (float i2 = 1f; i2 < range 1; i2  ){
        if (onsets[i] >= rangemult*(i2-1f) && onsets[i] <= rangemult*i2){
           sorted.Add(((rangemult*i2)*2f)*10f);
        }
    }
}

2. Here's what it does:

onsets --> a List containing the onsets found (excluding any 0's)

range --> Song Sample Depth (1024)

rangemult --> Is the maximum value in the list of onsets (so onsets.Max()) divided by the range so (max DIV range)

sorted --> list the sorted onsets are added to

(rangemult*i2)*2f)*10f --> i do this in order to get the value to be a whole number (which doesn't happen most of the time but it's really just for a sake of neatness - so for the most part it can be ignored)

in principle this algorithm would convert an array (0.1, 0.2, 0.4, 0.45, 0.5) with

range = 10 to 2, 4, 8, 9, 10

range = 20 to 4, 8, 16, 18, 20

etc...

3. so given this why is it that when 1024 is set as range the maximum value in sorted is always 20?

Additional info:

• i'm using a lomont FFT
• 1024 is constant throughout the onset detection algo
• treat onsets.max() as always 1 (i'm yet to find an instance where onsets.Max() is not 1)

I greatly appreciate it if you can provide even the smallest hint as to what's wrong - if there is not enough information here or the information is uneeded please inform me as i'm still new so i have hard time trying to explain my questions in an accurate manner - thankyou for understanding :)

CodePudding user response：

Given your apparent purpose, all you need is a simple LINQ statement:

var rangemult = range/onsets.Max();
var sorted = onsets.Select(onset => onset*rangemult).ToList();

However, this doesn't round the result to integers. You can add any desired rounding such as Math.Floor or Math.Round or Math.Ceil in the Select:

var sorted = onsets.Select(onset => Math.Round(onset*rangemult)).ToList();