public void GetSamples_Request123SamplesFrom1ChannelAudio_ReturnsSamplesFor1Channel()
{
var samples = _helper.GetSamples(123);
Assert.AreEqual(123, samples.GetLength(0));
Assert.AreEqual(1, samples.GetLength(1));
}
/// ------------------------------------------------------------------------------------
public IEnumerable <TimeSpan> GetNaturalBreaks()
{
uint requestedSamples = (uint)StreamReader.TotalTime.TotalMilliseconds;
//(StreamReader.SampleCount > uint.MaxValue) ? uint.MaxValue : (uint)StreamReader.SampleCount;
if (requestedSamples > 0)
{
var samples = AudioFileHelper.GetSamples(StreamReader, requestedSamples);
uint remainingSamples = (uint)samples.GetLength(0);
if (remainingSamples > 0)
{
uint lastBreak = 0;
var millisecondsPerSample = StreamReader.TotalTime.TotalMilliseconds / remainingSamples;
_adjacentSamplesToFactorIntoAdjustedScore = (uint)(_settings.AutoSegmenterPreferrerdPauseLengthInMilliseconds / millisecondsPerSample);
var minSamplesPerSegment = (uint)(_settings.AutoSegmenterMinimumSegmentLengthInMilliseconds / millisecondsPerSample);
var maxSamplesPerSegment = (uint)(_settings.AutoSegmenterMaximumSegmentLengthInMilliseconds / millisecondsPerSample);
uint idealSegmentLengthInSamples = (uint)Math.Ceiling((minSamplesPerSegment + maxSamplesPerSegment) / 2.0);
while (remainingSamples >= maxSamplesPerSegment)
{
if (remainingSamples < idealSegmentLengthInSamples * 2)
{
idealSegmentLengthInSamples = remainingSamples / 2;
}
uint samplesOnEitherSideOfTarget = idealSegmentLengthInSamples + _adjacentSamplesToFactorIntoAdjustedScore - minSamplesPerSegment;
uint targetBreak = lastBreak + idealSegmentLengthInSamples;
uint bestBreak = targetBreak;
double[] rawScores = new double[idealSegmentLengthInSamples * 2 + 1];
double[] adjustedScores = new double[idealSegmentLengthInSamples * 2 + 1];
rawScores[idealSegmentLengthInSamples] = ComputeRawScore(samples, targetBreak);
double bestScore = double.MaxValue;
double averageScore = 0;
for (uint i = 1; i < samplesOnEitherSideOfTarget; i++)
{
if (i < idealSegmentLengthInSamples)
{
rawScores[idealSegmentLengthInSamples + i] = ComputeRawScore(samples, targetBreak + i);
rawScores[idealSegmentLengthInSamples - i] = ComputeRawScore(samples, targetBreak - i);
}
if (i >= _adjacentSamplesToFactorIntoAdjustedScore)
{
// DEBUG code if ((targetBreak - i) * millisecondsPerSample < 138939 && lastBreak > 138939 - maxSamplesPerSegment)
//{
// System.Diagnostics.Debug.WriteLine("Position = " + (lastBreak + idealSegmentLengthInSamples + i) + "; Raw score = " + rawScores[idealSegmentLengthInSamples + i]);
// System.Diagnostics.Debug.WriteLine("Position = " + (lastBreak + idealSegmentLengthInSamples - i) + "; Raw score = " + rawScores[idealSegmentLengthInSamples - i]);
//}
double distanceFactor = Math.Pow(i * _settings.AutoSegmenterOptimumLengthClampingFactor + 1, 2);
uint iAdjust = idealSegmentLengthInSamples + i - _adjacentSamplesToFactorIntoAdjustedScore;
double totalNewAdjustedScores = adjustedScores[iAdjust] = ComputeAdjustedScore(rawScores, iAdjust, distanceFactor);
if (adjustedScores[iAdjust] < bestScore)
{
bestScore = adjustedScores[iAdjust];
bestBreak = lastBreak + iAdjust;
}
iAdjust = idealSegmentLengthInSamples - i + _adjacentSamplesToFactorIntoAdjustedScore;
adjustedScores[iAdjust] = ComputeAdjustedScore(rawScores, iAdjust, distanceFactor);
totalNewAdjustedScores += adjustedScores[iAdjust];
if (adjustedScores[iAdjust] < bestScore)
{
bestScore = adjustedScores[iAdjust];
bestBreak = lastBreak + iAdjust;
}
uint samplesInPrevAvg = (1 + 2 * (i - _adjacentSamplesToFactorIntoAdjustedScore - 1));
averageScore = (averageScore * samplesInPrevAvg + totalNewAdjustedScores) / (samplesInPrevAvg + 2);
if (bestScore < averageScore / 2 && i < idealSegmentLengthInSamples &&
rawScores[idealSegmentLengthInSamples + i] < rawScores[idealSegmentLengthInSamples + i + 1] &&
rawScores[idealSegmentLengthInSamples - i] < rawScores[idealSegmentLengthInSamples - i - 1])
{
break;
}
}
}
remainingSamples -= (bestBreak - lastBreak);
lastBreak = bestBreak;
yield return(TimeSpan.FromMilliseconds(millisecondsPerSample * bestBreak));
}
if (remainingSamples > 0)
{
yield return(StreamReader.TotalTime);
}
}
}
}