source: OniSplit/Sound/WavImporter.cs@ 1134

using System;
using System.IO;

namespace Oni.Sound
{
    internal class WavImporter : Importer
    {
        public override void Import(string filePath, string outputDirPath)
        {
            var wav = WavFile.FromFile(filePath);

            if (wav.Format != WavFormat.Pcm && wav.Format != WavFormat.Adpcm)
            {
                Console.Error.WriteLine("Unsupported WAV format (0x{0:X})", wav.Format);
                return;
            }

            if (wav.ChannelCount != 1 && wav.ChannelCount != 2)
            {
                Console.Error.WriteLine("Unsupported number of channels ({0})", wav.ChannelCount);
                return;
            }

            if (wav.SampleRate != 22050 && wav.SampleRate != 44100)
            {
                Console.Error.WriteLine("Unsupported sample rate ({0} Hz)", wav.SampleRate);
                return;
            }

            if (wav.ExtraData.Length > 32)
                throw new NotSupportedException(string.Format("Unsupported wave format extra data size ({0})", wav.ExtraData.Length));

            BeginImport();
            WriteSNDD(Path.GetFileNameWithoutExtension(filePath), wav);
            Write(outputDirPath);
        }

        private void WriteSNDD(string name, WavFile wav)
        {
            float duration = wav.SoundData.Length * 8.0f / wav.BitsPerSample;
            duration /= wav.SampleRate;
            duration /= wav.ChannelCount;
            duration *= 60.0f;

            var sndd = CreateInstance(TemplateTag.SNDD, name);

            using (var writer = sndd.OpenWrite(8))
            {
                writer.Write((short)wav.Format);
                writer.WriteInt16(wav.ChannelCount);
                writer.Write(wav.SampleRate);
                writer.Write(wav.AverageBytesPerSecond);
                writer.WriteInt16(wav.BlockAlign);
                writer.WriteInt16(wav.BitsPerSample);
                writer.WriteInt16(wav.ExtraData.Length);
                writer.Write(wav.ExtraData);
                writer.Skip(32 - wav.ExtraData.Length);
                writer.Write((short)duration);
                writer.Write(wav.SoundData.Length);
                writer.Write(WriteRawPart(wav.SoundData));
            }
        }
    }
}