cordova-plugin-media-with-compression

This plugin is a modified version of cordova-plugin-media that provides the ability to record and play back audio files on a device. Included are new methods (iOS and Android only) to pause recording, resume recording and to query the audio input power levels.

This plugin uses MPEG4 compression for iOS and (as of version 1.0.21) Android audio recording. On iOS, this results in a significant reduction in the recorded audio file size when compared to the stock Media plugin.

Since Android and iOS will record MPEG4 encoded audio with this plugin, the files generated are now compatible for playback across both platforms.

A .m4a file extension is required.

The reduction in file size is required for efficient online/offline storage and retrieval of the audio files. The smaller file size allows the audio file to be efficiently (smaller payload) uploaded to a server for storage and retrieved (while the device is online) for storage within the device file system for offline (disconnected) playback. This is a feature supported by Alpha Anywhere.

This plugin is tightly integrated within the Alpha Anywhere Cordova App Builder. Alpha Anywhere is a Rapid Mobile Application Development and Deployment platform.

New methods include (iOS and Android only):

recordAudioWithCompression(options): The options object includes the NumberOfChannels and the SampleRate. See the recordAudioWithCompression method description below for further details.

pauseRecord(): Pause the existing recording session. See the pauseRecord method description below for further details.

resumeRecord(): Resume the existing recording session. See the resumeRecord method description below for further details.

getRecordLevels(): On iOS devices, returns dB of the averagePower and the peakPower from the recorder input. On Android devices, returns an approximation of dB (SPL), derived from the maximum absolute amplitude that was sampled since the last call to this method.
See the getRecordLevels method description below for further details.

NOTE: The current implementation does not adhere to a W3C specification for media capture, and is provided for convenience only. A future implementation will adhere to the latest W3C specification and may deprecate the current APIs.

This plugin defines a global Media Constructor.

Although in the global scope, it is not available until after the deviceready event.

document.addEventListener("deviceready", onDeviceReady, false);
function onDeviceReady() {
    console.log(Media);
}

Installation

cordova plugin add cordova-media-with-compression

Supported Platforms

• Android
• iOS

Media

var media = new Media(src, mediaSuccess, [mediaError], [mediaStatus]);

Parameters

• src: A URI containing the audio content. (DOMString)

• mediaSuccess: (Optional) The callback that executes after a Media object has completed the current play, record, or stop action. (Function)

• mediaError: (Optional) The callback that executes if an error occurs. (Function)

• mediaStatus: (Optional) The callback that executes to indicate status changes. (Function)

Constants

The following constants are reported as the only parameter to the mediaStatus callback:

• Media.MEDIA_NONE = 0;
• Media.MEDIA_STARTING = 1;
• Media.MEDIA_RUNNING = 2;
• Media.MEDIA_PAUSED = 3;
• Media.MEDIA_STOPPED = 4;

Methods

• media.getCurrentPosition: Returns the current position within an audio file.

• media.getDuration: Returns the duration of an audio file.

• media.play: Start or resume playing an audio file.

• media.pause: Pause playback of an audio file.

• media.release: Releases the underlying operating system's audio resources.

• media.seekTo: Moves the position within the audio file.

• media.setVolume: Set the volume for audio playback.

• media.startRecord: Start recording an audio file, uses MPEG4 compression on iOS and Android.

• media.pauseRecord: Pause the recording session in progresss.

• media.resumeRecord: Resume the recording session in progress.

• media.startRecordWithCompression: Start recording an audio file, with SampleRate and NumberOfChannels specified. Uses MPEG4 compression. iOS and Android only.

• media.stopRecord: Stop recording an audio file.

• media.stop: Stop playing an audio file.

• media.getRecordLevels: On iOS devices, returns dB of the averagePower and the peakPower from the recorder input. On Android devices, returns an approximation of dB (SPL), derived from the maximum absolute amplitude that was sampled since the last call to this method.

Additional ReadOnly Parameters

• position: The position within the audio playback, in seconds.

  • Not automatically updated during play; call getCurrentPosition to update.

• duration: The duration of the media, in seconds.

media.getCurrentPosition

Returns the current position within an audio file. Also updates the Media object's position parameter.

media.getCurrentPosition(mediaSuccess, [mediaError]);

Parameters

• mediaSuccess: The callback that is passed the current position in seconds.

• mediaError: (Optional) The callback to execute if an error occurs.

Quick Example

// Audio player
//
var my_media = new Media(src, onSuccess, onError);

// Update media position every second
var mediaTimer = setInterval(function () {
    // get media position
    my_media.getCurrentPosition(
        // success callback
        function (position) {
            if (position > -1) {
                console.log((position) + " sec");
            }
        },
        // error callback
        function (e) {
            console.log("Error getting pos=" + e);
        }
    );
}, 1000);

media.getDuration

Returns the duration of an audio file in seconds. If the duration is unknown, it returns a value of -1.

media.getDuration();

Quick Example

// Audio player
//
var my_media = new Media(src, onSuccess, onError);

// Get duration
var counter = 0;
var timerDur = setInterval(function() {
    counter = counter + 100;
    if (counter > 2000) {
        clearInterval(timerDur);
    }
    var dur = my_media.getDuration();
    if (dur > 0) {
        clearInterval(timerDur);
        document.getElementById('audio_duration').innerHTML = (dur) + " sec";
    }
}, 100);

media.pause

Pauses playing an audio file.

media.pause();

Quick Example

// Play audio
//
function playAudio(url) {
    // Play the audio file at url
    var my_media = new Media(url,
        // success callback
        function () { console.log("playAudio():Audio Success"); },
        // error callback
        function (err) { console.log("playAudio():Audio Error: " + err); }
    );

    // Play audio
    my_media.play();

    // Pause after 10 seconds
    setTimeout(function () {
        media.pause();
    }, 10000);
}

media.play

Starts or resumes playing an audio file.

media.play();

Quick Example

// Play audio
//
function playAudio(url) {
    // Play the audio file at url
    var my_media = new Media(url,
        // success callback
        function () {
            console.log("playAudio():Audio Success");
        },
        // error callback
        function (err) {
            console.log("playAudio():Audio Error: " + err);
        }
    );
    // Play audio
    my_media.play();
}

iOS Quirks

• numberOfLoops: Pass this option to the play method to specify the number of times you want the media file to play, e.g.:

    var myMedia = new Media("http://audio.ibeat.org/content/p1rj1s/p1rj1s_-_rockGuitar.mp3")
    myMedia.play({ numberOfLoops: 2 })

• playAudioWhenScreenIsLocked: Pass in this option to the play method to specify whether you want to allow playback when the screen is locked. If set to true (the default value), the state of the hardware mute button is ignored, e.g.:

    var myMedia = new Media("http://audio.ibeat.org/content/p1rj1s/p1rj1s_-_rockGuitar.mp3")
    myMedia.play({ playAudioWhenScreenIsLocked : false })

• order of file search: When only a file name or simple path is provided, iOS searches in the www directory for the file, then in the application's documents/tmp directory:

    var myMedia = new Media("audio/beer.mp3")
    myMedia.play()  // first looks for file in www/audio/beer.mp3 then in <application>/documents/tmp/audio/beer.mp3

Since iOS 10 it's mandatory to add a NSMicrophoneUsageDescription in the info.plist.

• NSMicrophoneUsageDescription describes the reason that the app accesses the user’s microphone.

When the system prompts the user to allow access, this string is displayed as part of the dialog box.

This string has been hard coded with the following text to allow the plugin to be used by PhoneGap Build as well as the Cordova CLI:

• NSMicrophoneUsageDescription: This app requires access to the microphone to record audio.

media.release

Releases the underlying operating system's audio resources. This is particularly important for Android, since there are a finite amount of OpenCore instances for media playback. Applications should call the release function for any Media resource that is no longer needed.

media.release();

Quick Example

// Audio player
//
var my_media = new Media(src, onSuccess, onError);

my_media.play();
my_media.stop();
my_media.release();

media.seekTo

Sets the current position within an audio file.

media.seekTo(milliseconds);

Parameters

• milliseconds: The position to set the playback position within the audio, in milliseconds.

Quick Example

// Audio player
//
var my_media = new Media(src, onSuccess, onError);
    my_media.play();
// SeekTo to 10 seconds after 5 seconds
setTimeout(function() {
    my_media.seekTo(10000);
}, 5000);

media.setVolume

Set the volume for an audio file.

media.setVolume(volume);

Parameters

• volume: The volume to set for playback. The value must be within the range of 0.0 to 1.0.

Supported Platforms

• Android
• iOS

Quick Example

// Play audio
//
function playAudio(url) {
    // Play the audio file at url
    var my_media = new Media(url,
        // success callback
        function() {
            console.log("playAudio():Audio Success");
        },
        // error callback
        function(err) {
            console.log("playAudio():Audio Error: "+err);
    });

    // Play audio
    my_media.play();

    // Mute volume after 2 seconds
    setTimeout(function() {
        my_media.setVolume('0.0');
    }, 2000);

    // Set volume to 1.0 after 5 seconds
    setTimeout(function() {
        my_media.setVolume('1.0');
    }, 5000);
}

media.startRecord

Starts recording an audio file.

media.startRecord();

Supported Platforms

• Android
• iOS

Quick Example

// Record audio
//
function recordAudio() {
    var src = "myrecording.m4a";
    var mediaRec = new Media(src,
        // success callback
        function() {
            console.log("recordAudio():Audio Success");
        },

        // error callback
        function(err) {
            console.log("recordAudio():Audio Error: "+ err.code);
        });

    // Record audio
    mediaRec.startRecord();
}

Android Quirks

• Android devices record audio in MPEG4 format with this plugin. The specified file should end with a .m4a extension.
• The hardware volume controls are wired up to the media volume while any Media objects are alive. Once the last created Media object has release() called on it, the volume controls revert to their default behaviour. The controls are also reset on page navigation, as this releases all Media objects.

iOS Quirks

• iOS devices will record in MPEG4 format with this plugin. The specified file should end with a .m4a and an error is returned if the file name extension is not correct.

• If a full path is not provided, the recording is placed in the application's documents/tmp directory. This can be accessed via the File API using LocalFileSystem.TEMPORARY. Any subdirectory specified at record time must already exist.

• Files can be recorded and played back using the documents URI:

    var myMedia = new Media("documents://beer.m4a")

media.startRecordWithCompression (options)

Starts recording an audio file at the specified sample rate and number of audio channels.

Options object may include:

SampleRate: 44100, 32000, 16000, 12000, 8000 This is the sample rate in hz.

NumberOfChannels: 1 or 2

All iOS and Android devices currently support 1 input channel. This option is provided in anticipation of future device enhancements. A single channel recording is half the size of a stereo recording and unless the device supports a pair of microphones, use a single channel.

media.startRecordWithCompression(options);

Supported Platforms

• Android
• iOS

Quick Example

// Record audio with compression
//
function recordCompressedAudio() {
    var src = "myrecording.m4a";
    var mediaRec = new Media(src,
        // success callback
        function() {
            console.log("recordCompressedAudio():Audio Success");
        },

        // error callback
        function(err) {
            console.log("recordCompressedAudio():Audio Error: "+ err.code);
        });

    // Record MPEG compressed audio, single channel at 16kHz
    var options = {
        SampleRate: 16000,
        NumberOfChannels: 1
    }

    mediaRec.startRecordWithCompression(options);
}

media.stop

Stops playing an audio file.

media.stop();

Quick Example

// Play audio
//
function playAudio(url) {
    // Play the audio file at url
    var my_media = new Media(url,
        // success callback
        function() {
            console.log("playAudio():Audio Success");
        },
        // error callback
        function(err) {
            console.log("playAudio():Audio Error: "+err);
        }
    );

    // Play audio
    my_media.play();

    // Pause after 10 seconds
    setTimeout(function() {
        my_media.stop();
    }, 10000);
}

media.pauseRecord

Pause the recording of an audio file. Recording may be resumed with the resumeRecord method.

media.pauseRecord();

Supported Platforms

• Android
• iOS

Quick Example

// Record audio and pause recording
//
function recordAudio() {
    var src = "myrecording.mp3";
    var mediaRec = new Media(src,
        // success callback
        function() {
            console.log("recordAudio():Audio Success");
        },

        // error callback
        function(err) {
            console.log("recordAudio():Audio Error: "+ err.code);
        }
    );

    // Record audio
    mediaRec.startRecord();

    // Pause recording after 10 seconds
    setTimeout(function() {
        mediaRec.pauseRecord();
    }, 10000);
}

media.resumeRecord

Resumes recording an audio file after the pauseRecord method has been called.

media.resumeRecord();

Supported Platforms

• Android
• iOS

Quick Example

// Record audio
//
function recordAudio() {
    var src = "myrecording.mp3";
    var mediaRec = new Media(src,
        // success callback
        function() {
            console.log("recordAudio():Audio Success");
        },

        // error callback
        function(err) {
            console.log("recordAudio():Audio Error: "+ err.code);
        }
    );

    // Record audio
    mediaRec.startRecord();

    // Pause recording after 10 seconds
    setTimeout(function() {
        mediaRec.pauseRecord();
    }, 10000);

    // Resume recording after 20 seconds
    setTimeout(function() {
        mediaRec.resumeRecord();
    }, 20000);
}

media.stopRecord

Stops recording an audio file.

media.stopRecord();

Supported Platforms

• Android
• iOS

Quick Example

// Record audio
//
function recordAudio() {
    var src = "myrecording.mp3";
    var mediaRec = new Media(src,
        // success callback
        function() {
            console.log("recordAudio():Audio Success");
        },

        // error callback
        function(err) {
            console.log("recordAudio():Audio Error: "+ err.code);
        }
    );

    // Record audio
    mediaRec.startRecord();

    // Stop recording after 10 seconds
    setTimeout(function() {
        mediaRec.stopRecord();
    }, 10000);
}

media.getRecordLevels

On iOS devices, returns dB of the averagePower and the peakPower from the recorder input. On Android devices, returns an approximation of the dB level (SPL), derived from the maximum absolute amplitude that was sampled since the last call to this method.

media.getRecordLevels();

Supported Platforms

• Android
• iOS

Quick Example

// Record audio and get record levels every 250ms
//

var _media = {};
_media.intervalTime = 250;
_media.intervalTimer = null;

function recordAudio() {
    var src = "myrecording.mp3";
    var mediaRecorder = new Media(src,
        // success callback
        function() {
            clearInterval(_media.intervalTimer);
            console.log("recordAudio():Audio Success");
        },

        // error callback
        function(err) {
            console.log("recordAudio():Audio Error: "+ err.code);
        }
    );

    _media.intervalTimer = setInterval(function(){
        getRecordingLevels(mediaRecorder);
    },_media.intervalTime);

    // Record audio
    mediaRecorder.startRecord();
}

function getRecordingLevels(mediaRec) {
    mediaRec.getRecordLevels(function(result){
        console.log(JSON.stringify(result));
    }, function() {
        console.log("Error -> getRecordLevels.")

    }
}

MediaError

A MediaError object is returned to the mediaError callback function when an error occurs.

Properties

• code: One of the predefined error codes listed below.

• message: An error message describing the details of the error.

Constants

• MediaError.MEDIA_ERR_ABORTED = 1
• MediaError.MEDIA_ERR_NETWORK = 2
• MediaError.MEDIA_ERR_DECODE = 3
• MediaError.MEDIA_ERR_NONE_SUPPORTED = 4