public async Task <ICanvasImage> RenderAsync(StorageFile selectedFile, IPeakProvider peakProvider, WaveFormRendererSettings settings)
{
var randomAcessStream = await selectedFile.OpenReadAsync();
using (var reader = new StreamMediaFoundationReader(randomAcessStream.AsStream()))
{
int bytesPerSample = (reader.WaveFormat.BitsPerSample / 8);
var samples = reader.Length / (bytesPerSample);
var samplesPerPixel = (int)(samples / settings.Width);
var stepSize = settings.PixelsPerPeak + settings.SpacerPixels;
peakProvider.Init(reader.ToSampleProvider(), samplesPerPixel * stepSize);
return(Render(peakProvider, settings));
}
}
[NotNull] private static MemoryStream NormalizeAudioData(byte[] data)
{
#if NCRUNCH
return(new MemoryStream(data));
#endif
//Construct reader which can read the audio (whatever format it is in)
var reader = new StreamMediaFoundationReader(new MemoryStream(data));
var sampleProvider = reader.ToSampleProvider();
// find the max peak
float max = 0;
var buffer = new float[reader.WaveFormat.SampleRate];
int read;
do
{
read = sampleProvider.Read(buffer, 0, buffer.Length);
if (read > 0)
{
max = Math.Max(max, Enumerable.Range(0, read).Select(i => Math.Abs(buffer[i])).Max());
}
} while (read > 0);
if (Math.Abs(max) < float.Epsilon || max > 1.0f)
{
throw new InvalidOperationException("Audio normalization failed to find a reasonable peak volume");
}
//Write (as wav) with soft clipping and peak volume normalization
var output = new MemoryStream((int)(reader.Length * 4));
var input = new SoftClipSampleProvider(new VolumeSampleProvider(sampleProvider)
{
Volume = 1 / max - 0.05f
});
reader.Position = 0;
WaveFileWriter.WriteWavFileToStream(output, input.ToWaveProvider16());
return(output);
}
