A library to encode the output of Web Audio API nodes as Opus and export in an Ogg container. Audio encoded and decoded using libopus v1.1.2. Audio resampling is performed by speexdsp 1.2RC3.
Encoded and muxed audio will be returned as typedArray in dataAvailable
event.
var rec = new Recorder([config]);
Creates a recorder instance.
- config - An optional configuration object (see config section below)
- bitRate (optional) Specifies the target bitrate in bits/sec. The encoder selects an application-specific default when this is not specified.
- bufferLength - (optional) The length of the buffer that the internal JavaScriptNode uses to capture the audio. Can be tweaked if experiencing performance issues. Defaults to
4096
. - encoderApplication - (optional) Specifies the encoder application. Supported values are
2048
- Voice,2049
- Full Band Audio,2051
- Restricted Low Delay. Defaults to2049
. - encoderFrameSize (optional) Specifies the frame size in ms used for encoding. Defaults to
20
. - encoderPath - (optional) Path to encoderWorker.min.js worker script. Defaults to
encoderWorker.min.js
- encoderSampleRate - (optional) Specifies the sample rate to encode at. Defaults to
48000
. Supported values are8000
,12000
,16000
,24000
or48000
. - encoderComplexity - (optional) Value between 0 and 10 which determines latency and processing for resampling.
0
is fastest with lowest complexity.10
is slowest with highest complexity. The encoder selects a default when this is not specified. - leaveStreamOpen - (optional) Keep the stream around when trying to
stop
recording, so you can re-start
without re-initStream
. Defaults tofalse
. - maxBuffersPerPage - (optional) Specifies the maximum number of buffers to use before generating an Ogg page. This can be used to lower the streaming latency. The lower the value the more overhead the ogg stream will incur. Defaults to
40
. - monitorGain - (optional) Sets the gain of the monitoring output. Gain is an a-weighted value between
0
and1
. Defaults to0
- numberOfChannels - (optional) The number of channels to record.
1
= mono,2
= stereo. Defaults to1
. Maximum2
channels are supported. - resampleQuality - (optional) Value between 0 and 10 which determines latency and processing for resampling.
0
is fastest with lowest quality.10
is slowest with highest quality. Defaults to3
. - streamPages - (optional) Library will fire
dataAvailable
event after each encoded page. Defaults tofalse
.
rec.addEventListener( type, listener[, useCapture] )
addEventListener will add an event listener to the event target. Available events are streamError
, streamReady
, dataAvailable
, start
, pause
, resume
and stop
.
rec.initStream()
initStream will request the user for permission to access the the audio stream and raise streamReady
or streamError
.
rec.pause()
pause will keep the stream and monitoring alive, but will not be recording the buffers. Will raise the pause event. Subsequent calls to resume will add to the current recording.
rec.removeEventListener( type, listener[, useCapture] )
removeEventListener will remove an event listener from the event target.
rec.resume()
resume will resume the recording if paused. Will raise the resume event.
rec.setMonitorGain( gain )
setMonitorGain will set the volume on what will be passed to the monitor. Monitor level does not affect the recording volume. Gain is an a-weighted value between 0
and 1
.
rec.start()
start will initalize the worker and begin capturing audio if the audio stream is ready. Will raise the start
event when started.
rec.stop()
stop will cease capturing audio and disable the monitoring and mic input stream. Will request the recorded data and then terminate the worker once the final data has been published. Will raise the stop
event when stopped.
rec.clearStream()
clearStream will stop and delete the stream got from initStream
, you will only ever call this manually if you have config.leaveStreamOpen
set to true
.
Recorder.isRecordingSupported()
Will return a truthy value indicating if the browser supports recording.
Prebuilt binaries are included in the build folder. However below are instructions if you want to build them yourself.
Install autoconf, automake, libtool and pckconfig.
On Mac you can do this using MacPorts
sudo port install automake autoconf libtool pkgconfig
Install uglify-js using the command npm install uglify-js -g
.
Make the dependencies using command make
!
make test
The required files to record audio to ogg/opus are build/recorder.min.js
and build/encoderWorker.min.js
. Optionally build/decoderWorker.min.js
will help decode ogg/opus files and build/waveWorker.min.js
is a helper to transform floating point PCM data into wave/pcm. The source files in src/
folder do not work without building process; it produces ReferenceError: _malloc is not defined
). You need to either use compiled file in build/
folder or build by yourself.