wavesurfer.js

Interactive navigable audio visualization using Web Audio and Canvas.

Browser support

wavesurfer.js works only in modern browsers supporting Web Audio (Chrome, Firefox, Safari, Opera etc).

It will fallback to Audio Element in other browsers (without graphics). You can also try wavesurfer.swf which is a Flash-based fallback with graphics.

API in examples

Create an instance:

var wavesurfer = Object.create(WaveSurfer);

Initialize it with a container element (plus some options):

wavesurfer.init({
    container: '#wave',
    waveColor: 'violet',
    progressColor: 'purple'
});

Subscribe to some events:

wavesurfer.on('ready', function () {
    wavesurfer.play();
});

Load an audio file from a URL:

wavesurfer.load('example/media/demo.wav');

See the example code here.

WaveSurfer Options

option	type	default	description
`audioContext`	string	`null`	Use your own previously initialized `AudioContext` or leave blank.
`audioRate`	float	`1`	Speed at which to play audio. Lower number is slower.
`backend`	string	`WebAudio`	`WebAudio` or `AudioElement`. In most cases you don't have to set this manually. `AudioElement` is a fallback for unsupported browsers.
`container`	mixed	none	CSS-selector or HTML-element where the waveform should be drawn. This is the only required parameter.
`cursorColor`	string	`#333`	The fill color of the cursor indicating the playhead position.
`cursorWidth`	integer	`1`	Measured in pixels.
`fillParent`	boolean	`true`	Whether to fill the entire container or draw only according to `minPxPerSec`.
`height`	integer	`128`	The height of the waveform. Measured in pixels.
`hideScrollbar`	boolean	`false`	Whether to hide the horizontal scrollbar when one would normally be shown.
`interact`	boolean	`true`	Whether the mouse interaction will be enabled at initialization. You can switch this parameter at any time later on.
`minPxPerSec`	integer	`50`	Minimum number of pixels per second of audio.
`pixelRatio`	integer	`window.devicePixelRatio`	Can be set to `1` for faster rendering.
`progressColor`	string	`#555`	The fill color of the part of the waveform behind the cursor.
`scrollParent`	boolean	`false`	Whether to scroll the container with a lengthy waveform. Otherwise the waveform is shrunk to the container width (see `fillParent`).
`skipLength`	float	`2`	Number of seconds to skip with the `skipForward()` and `skipBackward()` methods.
`waveColor`	string	`#999`	The fill color of the waveform after the cursor.

WaveSurfer Methods

All methods are intentionally public, but the most readily available are the following:

init(options) – Initializes with the options listed above.
destroy() – Removes events, elements and disconnects Web Audio nodes.
empty() – Clears the waveform as if a zero-length audio is loaded.
getCurrentTime() – Returns current progress in seconds.
getDuration() – Returns the duration of an audio clip in seconds.
load(url) – Loads audio from URL via XHR. Returns XHR object.
loadBlob(url) – Loads audio from a Blob or File object.
on(eventName, callback) – Subscribes to an event. See WaveSurfer Events section below for a list.
un(eventName, callback) – Unsubscribes from an event.
unAll() – Unsubscribes from all events.
pause() – Stops playback.
play([start[, end]]) – Starts playback from the current position. Optional start and end measured in seconds can be used to set the range of audio to play.
playPause() – Plays if paused, pauses if playing.
seekAndCenter(progress) – Seeks to a progress and centers view [0..1] (0 = beginning, 1 = end).
seekTo(progress) – Seeks to a progress [0..1] (0=beginning, 1=end).
setFilter(filters) - For inserting your own WebAudio nodes into the graph. See Connecting Filters below.
setPlaybackRate(rate) – Sets the speed of playback (0.5 is half speed, 1 is normal speed, 2 is double speed and so on).
setVolume(newVolume) – Sets the playback volume to a new value [0..1] (0 = silent, 1 = maximum).
skip(offset) – Skip a number of seconds from the current position (use a negative value to go backwards).
skipBackward() - Rewind skipLength seconds.
skipForward() - Skip ahead skipLength seconds.
stop() – Stops and goes to the beginning.
toggleMute() – Toggles the volume on and off.
toggleInteraction() – Toggle mouse interaction.
toggleScroll() – Toggles scrollParent.

Connecting Filters

You can insert your own Web Audio nodes into the graph using the method setFilter(). Example:

var lowpass = wavesurfer.backend.ac.createBiquadFilter();
wavesurfer.backend.setFilter(lowpass);

WaveSurfer Events

General events:

error – Occurs on error. Callback will receive (string) error message.
finish – When it finishes playing.
loading – Fires continuously when loading via XHR or drag'n'drop. Callback will receive (integer) loading progress in percents [0..100] and (object) event target.
mouseup - When a mouse button goes up. Callback will receive MouseEvent object.
pause – When audio is paused.
play – When play starts.
ready – When audio is loaded, decoded and the waveform drawn.
scroll - When the scrollbar is moved. Callback will receive a ScrollEvent object.
seek – On seeking. Callback will receive (float) progress [0..1].

Region events (exposed by the Regions plugin):

region-in – When playback enters a region. Callback will receive the Region object.
region-out– When playback leaves a region. Callback will receive the Region object.
region-mouseenter - When the mouse moves over a region. Callback will receive the Region object, and a MouseEvent object.
region-mouseleave - When the mouse leaves a region. Callback will receive the Region object, and a MouseEvent object.
region-click - When the mouse clicks on a region. Callback will receive the Region object, and a MouseEvent object.
region-dblclick - When the mouse double-clicks on a region. Callback will receive the Region object, and a MouseEvent object.
region-created – When a region is created. Callback will receive the Region object.
region-updated – When a region is updated. Callback will receive the Region object.
region-update-end – When dragging or resizing is finished.
region-removed – When a region is removed. Callback will receive the Region object.

Regions Plugin

Regions are visual overlays on waveform that can be used to play and loop portions of audio. Regions can be dragged and resized.

Visual customization is possible via CSS (using the selectors .wavesurfer-region and .wavesurfer-handle).

To enable the plugin, add the script plugin/wavesurfer.regions.js to your page.

After doing that, use wavesurfer.addRegion() to create Region objects.

Exposed Methods

addRegion(options) – Creates a region on the waveform. Returns a Region object. See Region Options, Region Methods and Region Events below.
clearRegions() – Removes all regions.
enableDragSelection(options) – Lets you create regions by selecting. areas of the waveform with mouse. options are Region objects' params (see below).

Region Options

option	type	default	description
`id`	string	random	The id of the region.
`start`	float	`0`	The start position of the region (in seconds).
`end`	float	`0`	The end position of the region (in seconds).
`loop`	boolean	`false`	Whether to loop the region when played back.
`drag`	boolean	`true`	Allow/dissallow dragging the region.
`resize`	boolean	`true`	Allow/dissallow resizing the region.
`color`	string	`"rgba(0, 0, 0, 0.1)"`	HTML color code.

Region Methods

remove() - Remove the region object.
update(options) - Modify the settings of the region.
play() - Play the audio region from the start to end position.

Region Events