Wavesurfer.js: What is peak and how to Generate?

Created on 19 Jul 2017 · 6Comments · Source: katspaugh/wavesurfer.js

Hello,
this is not a bug, this is a question
I'm very new to audio part. i got many questions come in my mind.
1)what is peak?
2)how can i generate peak format data form mp3 using c#
3)Peak data is json array data?

4) and how can i play large(2 hours) audio while loading.
Please help me, i'm getting so much confused.

question

Source

smohammedyasin

Most helpful comment

Hello Guy,
Finally i came to use NAudio library to generate peaks using .net(visual studio). this post may help others or get idea to save peaks with mp3 or wav file.


using(var reader = new AudioFileReader(file))
{
    var samples = reader.Length / (reader.WaveFormat.Channels * reader.WaveFormat.BitsPerSample / 8);

    var max = 0.0f;
    // waveform will be a maximum of 4000 pixels wide:
    var batch = (int)Math.Max(40, samples / 4000);

    float[] buffer = new float[batch];
    int read;

    while((read = reader.Read(buffer,0,batch)) == batch)
    {
        for(int n = 0; n < read; n++)
        {
            max = Math.Max(Math.Abs(buffer[n]), max);
        };
        console.write(max);//peak ex: 0.342424, this can be store in array or .peak file 
      console.write(',');
        max = 0;    

    }
}

source link : https://stackoverflow.com/questions/13629277/analyzing-wav-and-drawing-a-graph

smohammedyasin on 9 Aug 2017

❤1 👍1

All 6 comments

1) The visualization of the audio.
2) Don't know.
3) No, it's just numbers in an array. Does not have to be JSON.
4) You will need to have your audio load in as a stream from your server...

agamemnus on 20 Jul 2017

Take a look at this issue: https://github.com/katspaugh/wavesurfer.js/issues/1141

There you have links and resources explaining how to extract peaks and prepare them for wavesurfer. For playing large files before they download entirely, you can try with MediaElement and a server that supports partial byte range requests (I use cloudfront).

matixmatix on 21 Jul 2017

I have also found that large audio files need peak data added in chunks (of their constituent audio data), or there will be memory issues.

agamemnus on 21 Jul 2017

@agamemnus , @matixmatix is possible to show waveform half section like this site audio mack
and still i'm looking for solution to convert peaks from wav or mp3 :-(

smohammedyasin on 24 Jul 2017

Hello Guy,
Finally i came to use NAudio library to generate peaks using .net(visual studio). this post may help others or get idea to save peaks with mp3 or wav file.


using(var reader = new AudioFileReader(file))
{
    var samples = reader.Length / (reader.WaveFormat.Channels * reader.WaveFormat.BitsPerSample / 8);

    var max = 0.0f;
    // waveform will be a maximum of 4000 pixels wide:
    var batch = (int)Math.Max(40, samples / 4000);

    float[] buffer = new float[batch];
    int read;

    while((read = reader.Read(buffer,0,batch)) == batch)
    {
        for(int n = 0; n < read; n++)
        {
            max = Math.Max(Math.Abs(buffer[n]), max);
        };
        console.write(max);//peak ex: 0.342424, this can be store in array or .peak file 
      console.write(',');
        max = 0;    

    }
}

source link : https://stackoverflow.com/questions/13629277/analyzing-wav-and-drawing-a-graph

smohammedyasin on 9 Aug 2017

❤1 👍1

@smohammedyasin have you slove it ？ cloud you share your demo ?