waveform.js

Waveform generation from audio file using BBC audiowaveform C++ program.

How to install

git clone https://github.com/loretoparisi/waveform.js
cd waveform.js/
npm install

How to generate a waveform

To generate a waveform from an wav audio file you can use the waveform api or the png api. You need to specify the input wav audio file, and the output file, that will be a json file or a png image. Both the api are Promise.

var wv = new Waveform({});
wv.waveform({}, 'sample.wav', 'sample.json')

How to generate a png image of the waveform

For a given wav file it is possibile to generate the waveform png image. Please use the png api and specify the following parameters:

{
    pixelsPerSecond: 7,
    bits: 8,
    width: 1800,
    height: 140,
    backgroundColor: 'FFFFFF00',
    waveformColor: 'FF0000',
    axisLabels: 1
}

You will get a nice waveform then

Please look at examples/png.js for an example.

How to generate a json representation of the waveform

For a given wav file it is possibile to generate the waveform as a json file. You use the waveform api with the following parameters:

{
    bits: 8
}

and you will obtain a json file with the format:

{
    "version": 2,
    "channels": 1,
    "sample_rate": 8000,
    "samples_per_pixel": 80,
    "bits": 8,
    "length": 26776,
    "data": []
}

where data will contain the waveform samples. Please look at examples/json.js for an example.

API Parameters

In the following the api parameters.

Waveform api

The waveform api is defined as Waveform.prototype.waveform = function (params, inputPath, outputPath) and it supports the following parameters:

* bits - Number of bits resolution when creating a waveform data file (either 8 or 16), default: 16
* -s <seconds>	--start <seconds>	Start time (seconds), default: 0
* -e <seconds>	--end <seconds>	End time (seconds). Not valid if --zoom is also specified

Png api

The png api is defined as follows Waveform.prototype.png = function (params, inputPath, outputPath) and it supports the following parameters:

* pixelsPerSecond - Zoom level (pixels per second), default: 100. Not valid if --end or --zoom is also specified
* bits - Number of bits resolution when creating a waveform data file (either 8 or 16), default: 16
* width - Width of output image (pixels), default: 800
* height - Height of output image (pixels), default: 250
* --border-color <color>	Border color (in rrggbb[aa] hex format), default: set by --colors option
* --background-color <color>	Background color (in rrggbb[aa] hex format), default: set by --colors option
* --waveform-color <color>	Waveform color (in rrggbb[aa] hex format), default: set by --colors option
* --no-axis-labels	Render PNG images without axis labels
* --with-axis-labels	Render PNG images with axis labels (default)
* --waveform-color <color>	Waveform color (in rrggbb[aa] hex format), default: set by --colors option
* -s <seconds>	--start <seconds>	Start time (seconds), default: 0
* -e <seconds>	--end <seconds>	End time (seconds). Not valid if --zoom is also specified

Supported platforms

We provide a binary version of audiowaveform program for linux and macOS platforms.

Disclaimer

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND. For more info about BBC waveform please look at https://github.com/bbc/audiowaveform