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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,140 @@ | ||
| using System; | ||
| using System.Collections.Generic; | ||
| using System.Linq; | ||
|
|
||
| namespace Cavern.QuickEQ.Equalization { | ||
| partial class Equalizer { | ||
| /// <summary> | ||
| /// Get the average level between the <paramref name="minFreq"/> and <paramref name="maxFreq"/>, | ||
| /// calculated in voltage scale, returned in dB scale. | ||
| /// </summary> | ||
| public double GetAverageLevel(double minFreq, double maxFreq) { | ||
| int i = 0, c = bands.Count; | ||
| while (i < c && bands[i].Frequency < minFreq) { | ||
| i++; | ||
| } | ||
| double sum = 0; | ||
| int n = 0; | ||
| while (i < c && bands[i].Frequency <= maxFreq) { | ||
| sum += Math.Pow(10, bands[i++].Gain * .05); | ||
| n++; | ||
| } | ||
| return 20 * Math.Log10(sum / n); | ||
| } | ||
|
|
||
| /// <summary> | ||
| /// Get the average level between the rolloff points (-<paramref name="range"/> dB points) | ||
| /// of the curve drawn by this <see cref="Equalizer"/>. <paramref name="stableRangeStart"/> and <paramref name="stableRangeEnd"/> are | ||
| /// the limits of a frequency band that can't be overly distorted on the curve and shall work for regression line calculation. | ||
| /// </summary> | ||
| public double GetAverageLevel(double range, double stableRangeStart, double stableRangeEnd) { | ||
| (double minFreq, double maxFreq) = GetRolloffs(range, stableRangeStart, stableRangeEnd); | ||
| return GetAverageLevel(minFreq, maxFreq); | ||
| } | ||
|
|
||
| /// <summary> | ||
| /// Detects valleys as band index ranges in the spectrum by comparing this <see cref="Equalizer"/> with an oversmoothed version. | ||
| /// </summary> | ||
| /// <param name="depth">Minimum valley in decibels for a range to be considered a result</param> | ||
| /// <param name="oversmoothing">Compare the current <see cref="Equalizer"/> | ||
| /// to a version which is smoothed by this many octaves</param> | ||
| public List<(int startInclusive, int stopExclusive)> GetValleys(double depth, double oversmoothing) { | ||
| Equalizer smoothed = (Equalizer)Clone(); | ||
| smoothed.Smooth(oversmoothing); | ||
| List<(int, int)> result = new List<(int, int)>(); | ||
| IReadOnlyList<Band> dryBands = bands, | ||
| wetBands = smoothed.bands; | ||
| bool inValley = false; | ||
| int valleyStarted = 0; | ||
| double maxInValley = 0; | ||
| for (int i = 0, c = dryBands.Count; i < c; i++) { | ||
| double valley = wetBands[i].Gain - dryBands[i].Gain; | ||
| bool willBeInValley = valley > 0; | ||
| if (maxInValley < valley) { | ||
| maxInValley = valley; | ||
| } | ||
| if (inValley != willBeInValley) { | ||
| if (willBeInValley) { | ||
| maxInValley = valley; | ||
| valleyStarted = i; | ||
| } else if (inValley && maxInValley >= depth) { | ||
| result.Add((valleyStarted, i)); | ||
| } | ||
| inValley = willBeInValley; | ||
| } | ||
| } | ||
| return result; | ||
| } | ||
|
|
||
| /// <summary> | ||
| /// Get the median level between the <paramref name="minFreq"/> and <paramref name="maxFreq"/>. | ||
| /// </summary> | ||
| public double GetMedianLevel(double minFreq, double maxFreq) { | ||
| int i = 0, c = bands.Count; | ||
| while (i < c && bands[i].Frequency < minFreq) { | ||
| i++; | ||
| } | ||
| int startBand = i; | ||
| while (i < c && bands[i].Frequency <= maxFreq) { | ||
| i++; | ||
| } | ||
|
|
||
| List<double> sortedBands = bands.GetRange(startBand, i - startBand).Select(x => x.Gain).ToList(); | ||
| sortedBands.Sort(); | ||
| return sortedBands[sortedBands.Count >> 1]; | ||
| } | ||
|
|
||
| /// <summary> | ||
| /// Get a line in the form of slope * log10(x) + intercept that fits the curve drawn by this <see cref="Equalizer"/>. | ||
| /// The regression line will only be calculated on the bands between <paramref name="startFreq"/> and <paramref name="endFreq"/>. | ||
| /// </summary> | ||
| public (double slope, double intercept) GetRegressionLine(double startFreq, double endFreq) { | ||
| double freqSum = 0, | ||
| freqSqSum = 0, | ||
| gainSum = 0, | ||
| mac = 0, | ||
| n = 0; | ||
| for (int i = GetFirstBandSafe(startFreq), c = bands.Count; i < c && bands[i].Frequency <= endFreq; i++) { | ||
| double freq = Math.Log10(bands[i].Frequency); | ||
| freqSum += freq; | ||
| freqSqSum += freq * freq; | ||
| gainSum += bands[i].Gain; | ||
| mac += freq * bands[i].Gain; | ||
| n++; | ||
| } | ||
| double slope = (n * mac - freqSum * gainSum) / (n * freqSqSum - freqSum * freqSum); | ||
| return (slope, (gainSum - slope * freqSum) / n); | ||
| } | ||
|
|
||
| /// <summary> | ||
| /// Get the rolloff points of the EQ by fitting a line on it and finding the first and last points | ||
| /// with a given range in decibels below it. <paramref name="stableRangeStart"/> and <paramref name="stableRangeEnd"/> are | ||
| /// the limits of a frequency band that can't be overly distorted on the curve and shall work for regression line calculation. | ||
| /// </summary> | ||
| public (double minFreq, double maxFreq) GetRolloffs(double range, double stableRangeStart, double stableRangeEnd) { | ||
| (double m, double b) = GetRegressionLine(stableRangeStart, stableRangeEnd); | ||
| int first = 0, last = bands.Count - 1; | ||
| while (first < last && bands[first].Gain + range < m * Math.Log10(bands[first].Frequency) + b) { | ||
| first++; | ||
| } | ||
| while (last > first && bands[last].Gain + range < m * Math.Log10(bands[last].Frequency) + b) { | ||
| last--; | ||
| } | ||
| return (bands[first].Frequency, bands[last].Frequency); | ||
| } | ||
|
|
||
| /// <summary> | ||
| /// Get the average level between the <paramref name="firstBand"/> (inclusive) and <paramref name="lastBand"/> (exclusive), | ||
| /// calculated in voltage scale, returned in dB scale. | ||
| /// </summary> | ||
| double GetAverageLevel(int firstBand, int lastBand) { | ||
| double sum = 0; | ||
| int n = 0; | ||
| while (firstBand < lastBand) { | ||
| sum += Math.Pow(10, bands[firstBand++].Gain * .05); | ||
| n++; | ||
| } | ||
| return 20 * Math.Log10(sum / n); | ||
| } | ||
| } | ||
| } |
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