MonoGame looping MP3 and OGG support

BGM.cs

// Loop support for MP3 and OGG in MonoGame
// by Jesuszilla
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Xml.Serialization;
using Microsoft.Xna.Framework.Audio;
using MP3Sharp;

public partial class BGM
{
    /// <summary>
    /// The volume for the BGM track.
    /// </summary>
    [XmlIgnoreAttribute]
    public float Volume
    {
        get { return volume; }
        set
        {
            if (value > 1.0F || value < 0.0F)
                throw new ArgumentOutOfRangeException("volume", value, "Must be in range [0.0, 1.0]");
            else
            {
                volume = value;

                if (bgmInstance != null)
                    bgmInstance.Volume = volume;
            }
        }
    }
    private float volume;

    /// <summary>
    /// Gets the value indicating whether or not the BGM is currently playing.
    /// </summary>
    [XmlIgnoreAttribute]
    public bool IsPlaying { get; private set; }

    /// <summary>
    /// Currently playing instance.
    /// </summary>
    [XmlIgnoreAttribute]
    private SoundEffectInstance bgmInstance;

    /// <summary>
    /// Loop start time.
    /// </summary>
    [XmlIgnoreAttribute]
    private TimeSpan loopStartTime;

    /// <summary>
    /// Loop time.
    /// </summary>
    [XmlIgnoreAttribute]
    private TimeSpan loopTime;

    /// <summary>
    /// If true, this BGM has loop points.
    /// </summary>
    [XmlIgnoreAttribute]
    private bool isLooped = false;

    [XmlIgnoreAttribute]
    byte[] introBytes;

    [XmlIgnoreAttribute]
    byte[] loopBytes;

    [XmlIgnoreAttribute]
    int sampleRate;

    [XmlIgnoreAttribute]
    AudioChannels channels;

    /// <summary>
    /// Parameterless constructor for XML.
    /// </summary>
    public BGM()
    {
    }

    /// <summary>
    /// Initializes a new instance of the <see cref="T:Blugen.Sound.BGM"/> class.
    /// </summary>
    /// <param name="filePath">File path to the BGM.</param>
    public void Initialize(string filePath, int loopStart = 0, int loopEnd = 0)
    {
        isLooped = (loopEnd - loopStart) > 0;

        using (FileStream fs = new FileStream(filePath, FileMode.Open))
        {
            // Let's see if it's an MP3 first.
            try
            {
                fs.Position = 0;
                using (MP3Stream mp3Dec = new MP3Stream(fs))
                {
                    sampleRate = mp3Dec.Frequency;
                    channels = (AudioChannels)mp3Dec.ChannelCount;
                    mp3Dec.Position = 0;
                    byte[] buffer = new byte[4096];
                    List<byte> decoded = new List<byte>();
                    int bytesRead = 0;
                    while ((bytesRead = mp3Dec.Read(buffer, 0, buffer.Length)) > 0)
                    {
                        decoded.AddRange(buffer.Take(bytesRead));
                    }
                    var db = decoded.ToArray();

                    if (isLooped)
                    {
                        // Regions
                        int loopStartByte = loopStart * (mp3Dec.ChannelCount << 1);
                        int loopEndByte = loopEnd * (mp3Dec.ChannelCount << 1);
                        int loopStartOffByte = loopStartByte - (loopStartByte % (mp3Dec.ChannelCount << 1)); // Align to byte boundary
                        int loopEndOffByte = loopEndByte - (loopEndByte % (mp3Dec.ChannelCount << 1)); // Align to byte boundary

                        // Region bytes
                        introBytes = db.Take(loopStartOffByte).ToArray();
                        loopBytes = db.Skip(loopStartOffByte).Take(loopEndOffByte - loopStartOffByte).ToArray();

                        loopStartTime = new TimeSpan((long)((loopStart*1.0) / mp3Dec.Frequency * 1E7));
                        loopTime = new TimeSpan((long)((loopEnd*1.0 - loopStart) / mp3Dec.Frequency * 1E7));
                    }
                    else
                        introBytes = db;
                }
            }
            catch (Exception e)
            {
                // Not a valid MP3, try Vorbis
                try
                {
                    using (NVorbis.VorbisReader vr = new NVorbis.VorbisReader(fs, false))
                    {
                        sampleRate = vr.SampleRate;
                        channels = (AudioChannels)vr.Channels;
                        float[] buffer = new float[1024];
                        List<byte> decoded = new List<byte>();
                        while (vr.ReadSamples(buffer, 0, buffer.Length) > 0)
                        {
                            for (int i = 0; i < buffer.Length; i++)
                            {
                                short temp = (short)(32767 * buffer[i]);
                                if (temp > 32767)
                                {
                                    decoded.Add(0xFF);
                                    decoded.Add(0x7F);
                                }
                                else if (temp < -32768)
                                {
                                    decoded.Add(0x80);
                                    decoded.Add(0x00);
                                }
                                decoded.Add((byte)temp);
                                decoded.Add((byte)(temp >> 8));
                            }
                        }
                        var db = decoded.ToArray();

                        if (isLooped)
                        {
                            // Regions
                            int loopStartByte = loopStart * (vr.Channels << 1);
                            int loopEndByte = loopEnd * (vr.Channels << 1);
                            int loopStartOffByte = loopStartByte - (loopStartByte % (vr.Channels << 1)); // Align to byte boundary
                            int loopEndOffByte = loopEndByte - (loopEndByte % (vr.Channels << 1)); // Align to byte boundary

                            // Region bytes
                            introBytes = db.Take(loopStartOffByte).ToArray();
                            loopBytes = db.Skip(loopStartOffByte).Take(loopEndOffByte - loopStartOffByte).ToArray();

                            loopStartTime = new TimeSpan((long)((loopStart * 1.0) / vr.SampleRate * 1E7));
                            loopTime = new TimeSpan((long)((loopEnd * 1.0 - loopStart) / vr.SampleRate * 1E7));
                        }
                        else
                            introBytes = db;
                    }
                }
                catch (Exception x)
                {

                }
            }

            if (introBytes != null)
            {
                bgmInstance = new DynamicSoundEffectInstance(sampleRate, channels);
                // Queue up everything needed for playing
                ((DynamicSoundEffectInstance)bgmInstance).SubmitBuffer(introBytes);
                if (loopBytes != null)
                {
                    for (int i = 0; i < 2; i++)
                    {
                        ((DynamicSoundEffectInstance)bgmInstance).SubmitBuffer(loopBytes);
                    }
                }
                ((DynamicSoundEffectInstance)bgmInstance).BufferNeeded += BgmInstance_BufferNeeded;
            }
        }
    }

    private void BgmInstance_BufferNeeded(object sender, EventArgs e)
    {
        if (loopBytes != null)
            ((DynamicSoundEffectInstance)bgmInstance).SubmitBuffer(loopBytes);
        else
            ((DynamicSoundEffectInstance)bgmInstance).SubmitBuffer(introBytes);
    }

    /// <summary>
    /// Plays the BGM.
    /// </summary>
    public void PlayBGM()
    {
        if (bgmInstance != null)
        {
            bgmInstance.Volume = Volume;
            bgmInstance.Play();

            IsPlaying = true;
        }
    }

    /// <summary>
    /// Pauses the BGM playback.
    /// </summary>
    public void PauseBGM()
    {
        if (bgmInstance != null)
        {
            bgmInstance.Pause();
            IsPlaying = false;
        }
    }

    /// <summary>
    /// Immediately stops the BGM playback and resets its position to the beginning.
    /// </summary>
    public void StopBGM()
    {
        if (bgmInstance != null)
        {
            bgmInstance.Stop(true);
            IsPlaying = false;
        }
    }
}

LICENSE

Copyright 2018 Jesuszilla

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.