public AudioInfo Decode(System.IO.Stream stream, float targetBitrate, string fileExt)
{
var length = stream.Length;
byte[] source = new byte[length];
// read the file into the buffer
stream.Read(source, 0, (int)length);
// now create a pinned handle, so that the Garbage Collector will not move this object
var _hGCFile = GCHandle.Alloc(source, GCHandleType.Pinned);
try
{
var buffer = ReadMonoFromStream(_hGCFile.AddrOfPinnedObject(), source.Length, (int) targetBitrate, -1, 0);
var result = new AudioInfo();
result.Samples = new Samples() { Values = buffer, Bitrate = (int)targetBitrate };
return result;
}
catch(Exception E)
{
Logger.WarnException("Audio decoding exception.", E);
return null;
}
finally
{
_hGCFile.Free();
}
}
public void Process(Audio item, AudioInfo info)
{
var tempogram = new Tempogram();
//get maximum values
Samples samples = new EnvelopeProcessor(factory).Build(info.Samples, 32, false);
var newSamples = new Samples()
{
Values = new float[samples.Values.Length], Bitrate = samples.Bitrate
};
var intensity = 0;
for (int i = 0; i < samples.Values.Length - 1; i++)
{
var diff = samples.Values[i + 1] - samples.Values[i];
samples.Values[i] = diff > 0 ? diff : 0; //разница между всеми амплитудами
newSamples.Values[i] = diff;
if (diff > minAmplitudeChangeForIntensityRate)
{
intensity++;
}
}
samples.Values[samples.Values.Length - 1] = 0;
newSamples.Values[samples.Values.Length - 1] = 0;
var durationOfTrack = samples.Values.Length / samples.Bitrate;//time of sound
var maxShift = (int)(samples.Values.Length * (maxRithmDuration / durationOfTrack));
var autoCorr1 = AutoCorr(samples.Values, maxShift, 5);
var autoCorr2 = AutoCorr(newSamples.Values, maxShift, 2);
var lengthCorr1 = (float)autoCorr1.Length;
var log2 = Math.Log(2);
var list1 = new List<KeyValuePair<float, float>>();
var list2 = new List<KeyValuePair<float, float>>();
for (int i = 0; i < lengthCorr1; i++)
{
var j = i / (float)lengthCorr1;
j = (float)(Math.Log(j + 1) / log2);
list1.Add(new KeyValuePair<float, float>(j, autoCorr1[i]));
var v = autoCorr2[i];
list2.Add(new KeyValuePair<float, float>(j, v > 0 ? v : 0));
}
tempogram.LongTempogram.Build(list1);
tempogram.ShortTempogram.Build(list2);
tempogram.Intensity = (float)intensity / durationOfTrack;
CalcTempo(tempogram);
//save to audio item
item.Data.Add(tempogram);
}
public void Process(Audio item, AudioInfo info)
{
if (item == null)
{
throw new ArgumentNullException("item");
}
SHA1HashDescriptor Descriptor = new SHA1HashDescriptor(item);
item.Data.Add(Descriptor);
}
/// <summary>
/// Gets audio from queue and process it
/// </summary>
protected virtual void AudioAnalys(IAudioDecoder decoder)
{
int counter = 0;
Audio item;
while ((item = GetItemFromQueue()) != null)
{
try
{
counter++;
//decode audio source to samples and mp3 tags extracting
AudioInfo info = null;
using (var stream = item.GetSourceStream())
{
info = decoder.Decode(stream, TargetBitrate, item.GetSourceExtension());
}
//normalize volume level
info.Samples.Normalize();
//launch sample processors
foreach (var processor in factory.CreateSampleProcessors())
{
try
{
processor.Process(item, info);
}
catch (Exception E)
{
Logger.WarnException("Audio processor exception.", E);
}
}
OnProgress(new ProgressChangedEventArgs(100 * (itemsCount - audioSourceQueue.Count) / itemsCount, null));
item.State = AudioState.Processed;
}
catch (Exception E)
{
Logger.ErrorException("Audio processing failed.", E);
item.State = AudioState.Bad;
}
}
}
public virtual void Process(Audio item, AudioInfo info)
{
//build amplitude envelope
var s = Build(info.Samples);
//resample
var resampler = Factory.CreateResampler();
var resampled = resampler.Resample(s, info.Samples.Bitrate * ((float)EnvelopeLength / info.Samples.Values.Length));
//build packed array
var envelope = new Envelope(resampled);
//save into audio item
item.Data.Add(envelope);
//build volumeDescriptor
var volDesc = new VolumeDescriptor();
volDesc.Build(s.Values);
item.Data.Add(volDesc);
}
