feat: initial whipser transcriber implementation

src/StreamShorts.Library/Media/NAudioService.cs

@@ -0,0 +1,45 @@
+
+using NAudio.Wave;
+
+namespace StreamShorts.Library.Media;
+
+/// <summary>
+/// Represents a service for processing audio files using NAudio.
+/// </summary>
+/// <inheritdoc/>
+internal class NAudioService : IAudioService
+{
+  public Stream ConvertMp3ToWav16(Stream mp3)
+  {
+    using var reader = new Mp3FileReader(mp3);
+    var outFormat = new WaveFormat(16000, reader.WaveFormat.Channels);
+    using var resampler = new MediaFoundationResampler(reader, outFormat);
+    var waveStream = new MemoryStream();
+    WaveFileWriter.WriteWavFileToStream(waveStream, resampler);
+    waveStream.Position = 0;
+    return waveStream;
+  }
+
+  public int GetNumberOfWavSegments(Stream wavStream, TimeSpan segmentDuration)
+  {
+    using var waveReader = new WaveFileReader(wavStream);
+    var totalDuration = waveReader.TotalTime;
+    var segmentCount = (int)Math.Ceiling(totalDuration.TotalMilliseconds / segmentDuration.TotalMilliseconds);
+    wavStream.Position = 0;
+    return segmentCount;
+  }
+
+  public Stream GetWavSegment(Stream wavStream, int segmentNumber, TimeSpan segmentDuration)
+  {
+    using var segmentWaveReader = new WaveFileReader(wavStream);
+    var segment = segmentWaveReader.ToSampleProvider()
+      .Skip(segmentNumber * segmentDuration)
+      .Take(segmentDuration);
+    var segmentProvider = segment.ToWaveProvider16();
+    var segmentStream = new MemoryStream();
+    WaveFileWriter.WriteWavFileToStream(segmentStream, segmentProvider);
+    segmentStream.Position = 0;
+    wavStream.Position = 0;
+    return segmentStream;
+  }
+}