New Post: Newbie Fade-Out Problems.

Hi and thanks for a great piece of software :)

I'm trying to use NAudio to trim wav files and then fade them in and out.
I have managed to trim and fade in with 0 problems, but when I try to use fade out rather than fading the end of the track, it fades from the beginning.
I have tried playing with different values for "int sample = 0;", but have had no luck.

Code I am using is from this forum from someone asking about fade out.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using NAudio;
using NAudio.Mixer;
using NAudio.Utils;
using NAudio.Wave;

namespace ALAMO
{

     


    public class FadeInOutSampleProvider : ISampleProvider
    {        
        enum FadeState
        {
            Silence,
            FadingIn,
            FullVolume,
            FadingOut,
        }

        private readonly object lockObject = new object();
        private readonly ISampleProvider source;
        private int fadeSamplePosition;
        private int fadeSampleCount;
        private FadeState fadeState;

        public FadeInOutSampleProvider(ISampleProvider source)
        {
            this.source = source;
            this.fadeState = FadeState.FullVolume;
        }

        public void BeginFadeIn(double fadeDurationInMilliseconds)
        {
            lock (lockObject)
            {
                fadeSamplePosition = 0;
                fadeSampleCount = (int)((fadeDurationInMilliseconds * source.WaveFormat.SampleRate) / 1000);
                fadeState = FadeState.FadingIn;
            }
        }

        public void BeginFadeOut(double fadeDurationInMilliseconds)
        {
            lock (lockObject)
            {
                fadeSamplePosition = 0;
                fadeSampleCount = (int)((fadeDurationInMilliseconds * source.WaveFormat.SampleRate) / 1000);
                fadeState = FadeState.FadingOut;
            }
        }

        public int Read(float[] buffer, int offset, int count)
        {
            int sourceSamplesRead = source.Read(buffer, offset, count);
            lock (lockObject)
            {
                if (fadeState == FadeState.FadingIn)
                {
                    FadeIn(buffer, offset, sourceSamplesRead);
                }
                else if (fadeState == FadeState.FadingOut)
                {
                    FadeOut(buffer, offset, sourceSamplesRead);
                }
                else if (fadeState == FadeState.Silence)
                {
                    ClearBuffer(buffer, offset, count);
                }
            }
            return sourceSamplesRead;
        }

        private static void ClearBuffer(float[] buffer, int offset, int count)
        {
            for (int n = 0; n < count; n++)
            {
                buffer[n + offset] = 0;
            }
        }

        private void FadeOut(float[] buffer, int offset, int sourceSamplesRead)
        {
            int sample = 0;
            while (sample < sourceSamplesRead)
            {
                float multiplier = 1.0f - (fadeSamplePosition / (float)fadeSampleCount);
                for (int ch = 0; ch < source.WaveFormat.Channels; ch++)
                {
                    buffer[offset + sample++] *= multiplier;
                }
                fadeSamplePosition++;
                if (fadeSamplePosition > fadeSampleCount)
                {
                    fadeState = FadeState.Silence;
                    // clear out the end
                    ClearBuffer(buffer, sample + offset, sourceSamplesRead - sample);
                    break;
                }
            }
        }

        private void FadeIn(float[] buffer, int offset, int sourceSamplesRead)
        {
            int sample = 0;
            while (sample < sourceSamplesRead)
            {
                float multiplier = (fadeSamplePosition / (float)fadeSampleCount);
                for (int ch = 0; ch < source.WaveFormat.Channels; ch++)
                {
                    buffer[offset + sample++] *= multiplier;
                }
                fadeSamplePosition++;
                if (fadeSamplePosition > fadeSampleCount)
                {
                    fadeState = FadeState.FullVolume;
                    // no need to multiply any more
                    break;
                }
            }
        }

        public WaveFormat WaveFormat
        {
            get { return source.WaveFormat; }
        }
              
           
    }
}

And I am calling it from a button on a Windows Form App with the following code:

var afr = new AudioFileReader(filename);
            var fader = new FadeInOutSampleProvider(afr);
            fader.BeginFadeOut(5500);
            var stwp = new NAudio.Wave.SampleProviders.SampleToWaveProvider(fader);
            WaveFileWriter.CreateWaveFile(filename, stwp); 

I am imagining that I am making a basic mistake as only been teaching myself C# for a week now, but would really appreciate help on this problem.

Thanks in advance