Trimming mp3 files using NAudio

Question

Is it possible to trim a MP3 file using NAudio? I am looking for a way to take a standard mp3 file and take a part of it and make it a seperate mp3.

Answer 1

Install NAudio from Nuget:

PM> Install-Package NAudio

Add using NAudio.Wave; and use this code:

void Main()
{
     var mp3Path = @"C:\Users\Ronnie\Desktop\podcasts\hanselminutes_0350.mp3";  
     var outputPath = Path.ChangeExtension(mp3Path,".trimmed.mp3");

     TrimMp3(mp3Path, outputPath, TimeSpan.FromMinutes(2), TimeSpan.FromMinutes(2.5));
}

void TrimMp3(string inputPath, string outputPath, TimeSpan? begin, TimeSpan? end)
{
    if (begin.HasValue && end.HasValue && begin > end)
        throw new ArgumentOutOfRangeException("end", "end should be greater than begin");

    using (var reader = new Mp3FileReader(inputPath))
    using (var writer = File.Create(outputPath))
    {           
        Mp3Frame frame;
        while ((frame = reader.ReadNextFrame()) != null)
        if (reader.CurrentTime >= begin || !begin.HasValue)
        {
            if (reader.CurrentTime <= end || !end.HasValue)
                writer.Write(frame.RawData,0,frame.RawData.Length);         
            else break;
        }
    }
}

Happy trails.

Answer 2

Yes, an MP3 file is a sequence of MP3 frames, so you can simply remove frames from the start or end to trim the file. NAudio can parse MP3 frames.

See this question for more details.