by tronix117 | v0.1.0-alpha.1
A nativescript-transcoder plugin, to transcode videos (use AVFoundation on iOS and android-transcoder on Android)
npm i --save nativescript-transcoder


WARNING, WORK IN PROGRESS, v1.0 excepted end of March

This plugins for nativescript brings video transcoding support.

  • Hardware transcoding on android through android-transcoder.
  • @todo Hardware transcoding on iOS through AVFoundation
  • @todo Software transcoding on iOS/Android through FFMpeg

The plugins support observing events as well as promises.

Only AAC audio is supported right now on Android, simulator camera is using 3GPP audio, so you can not test it with the simulator

For hardware mode, only 720p resolution is supported on android, other resolutions may not work on some devices, a way to select the best profile may be developed (Note for above for future developments on this plugin: CamcorderProfile is the way to go to retrieve all possible encoding resolutions, then we just need to select the best one according to settings).


tns plugin add nativescript-transcoder



const {
} = require('nativescript-transcoder');

const transcoder = new Transcoder(inputFilePath, {
videoBitrate: 1000 * 1000, // 1mbps
resolutionConstraint: 720,
videoCodec: TranscoderVideoCodec.H264,

transcoder.transcode().then(({ filePath }) => {
console.log(`Output file path: ${filePath}`);
}).catch((err) => {
console.log(`Error: ${err.type} - ${err.message}`);

transcoder.on(TranscoderEventList.Progress, (progress) => {
console.log(`Progress: ${progress}`);


import {
} from 'nativescript-transcoder';

const transcoder = new Transcoder(inputFilePath, {
videoBitrate: 1000 * 1000, // 1mbps
resolutionConstraint: 720,
videoCodec: TranscoderVideoCodec.H264,

transcoder.transcode().then(({ filePath }) => {
console.log(`Output file path: ${filePath}`);
}).catch((err: TranscoderException) => {
console.log(`Error: ${err.type} - ${err.message}`);

transcoder.on(TranscoderEventList.Progress, (progress: number) => {
console.log(`Progress: ${progress}`);



The main class you need to use, a transcoder can only be used for one transcoding.



Method Return type Description
constructor(filePath: string, options?: TranscoderOptions) Transcoder Initialize a transcoder, filePath is mandatory (input video).
transcode() Promise<TranscoderResult> Launch the transcoding
cancel() void Force cancel of the thread running the task


Property Default Description
@ObservableProperty progress: number null Progress of the transcoding, null if not applicable
@ObservableProperty status TranscoderStatus.Idle Status of the transcoding process
@readonly filePath: string N/A FilePath of file which will be transcoded.
@get/@set audioBitrate: number from options set/get audio bitrate
@get/@set videoBitrate: number from options set/get video bitrate


Name Callback Description
TranscoderEventList.Completed or completed (result: TranscoderResult) => void Emitted when the transcoding is done. You can access the output path from result.filePath.
TranscoderEventList.Canceled or canceled () => void The user has canceled the transcoding
TranscoderEventList.Progress or progress (progress: number) => void Called each time the progress change.
TranscoderEventList.Failed or failed (err: TranscoderException) => void An error occured while transcoding or attempting to transcode. See TranscoderException to see how to handle exceptions


Construct an object to pass as options to new Transcoder(filePath, options).

All options are optionals.

Property Default Description
videoBitrate: number null Adjust video bitrate
Default to null.
When null, try to use the same bitrate as input, but bitrate information can not always be retrieved on h264 on Android, as a result if encoding is necessary, bitrate will default to 1mbps (1000000).
audioBitrate: number null Adjust audio bitrate (in bps), default to null (keep bitrate)
videoCodec: TranscoderVideoCodec TranscoderVideoCodec.Auto Define the video codec to use. Be careful, all device does not support all codecs, use TranscoderVideoCodec.Auto if not sure.
audioCodec: TranscoderAudioCodec TranscoderVideoCodec.Aac Define the audio codec to use. Only AAC supported for now.
nativeTranscoder: TranscoderNativeTranscoder TranscoderNativeTranscoder.Hardware Define which native transcoder to use. Hardware is faster and better but FFMPEG is not dependant of what the device can or can not do. The hardware transcoder can always handle video taken by the device camera. Prefered choice is Hardware, but choose FFMPEG if video comes from unknown sources
resolutionConstraint: number null Define the output resolution of the video. Positive number represent a constraint on the smaller side of the video. Negative number represent a constraint on the larger side of the video. Important: the video will never be scalled up ! (null to keep the original format). Ex:
- input: 1920x1080, resolutionConstraint: 720, output: 1280x720
- input: 1920x1080, resolutionConstraint: -720, output: 720x405
strictResolutionConstraint: boolean false If this is true, the transcoder will through an error if the video can not be scaled according to the defined resolutionConstraint. Otherwise, it will use the nearest possible resolution. (ex: 480p can not be achieve with 3140x2160, if true then an exception will be thrown, if false then output resolution will be 848x477).



transcoder.on(TranscoderEventList.Failed, (err: TranscoderException) => {
switch (err.type) {
case TranscoderExceptionType.InvalidOutputFormat:
console.log('The device doesn\'t support the asked output')
default: // TranscoderExceptionType.Failed:
console.log('Unable to trasncode')


Property/method Default Description
type: TranscoderExceptionType null Type of transcoding error (see TranscoderExceptionType)
nativeError: any undefined May be the raw error rejected by the native transcoder.
constructor(type: TranscoderExceptionType, message: string, nativeError?: any): TranscoderException N/A Initialize a TranscoderException, prefered way is to inherit from that.


An enum containing all possible types

Prefered way is to use TranscoderExceptionType.Canceled instead of it's value ('CANCELED').

Key Value Description
Canceled 'CANCELED' User canceled exception
Failed 'FAILED' Generic failure error
InvalidInputFormat 'INVALID_INPUT' Generic error when Input can not be transcoded.
InvalidOutputResolution 'INVALID_INPUT' Happens when output resolution is not correct (like floating number).
InvalidOutputVideoCodec 'INVALID_OUTPUT_VIDEO_CODEC' Happens when no video codec correspond on the device.
InvalidOutputFormat 'INVALID_OUTPUT_FORMAT' Happens when at the end, the device is not capable to hardware transcode a given format


Apache License Version 2.0, January 2004