HLS Transcoder

THIS PACKAGE IS STILL UNDER ACTIVE DEVELOPMENT, API CHANGES CAN AND LIKELY WILL HAPPEN REGARDLESS OF WHETHER THEY ARE DOCUMENTED BELOW

An FFMPEG Wrapper heavily inspired by simple-hls, to transcode Multi-bitrate HLS videos.

Installation:

Via npm:

``bash
npm install hls-transcoder
`

$3

#### ffmpeg and ffprobe

hls-transcoder requires both ffmpeg, and ffprobe. If ffmpeg and ffprobe are installed on your system, and added to PATH, hls-transcoder will try invoking each program via ffmpeg and ffprobe respectively.

Alternatively, you can use pre-compiled binaries, ie with @ffmpeg-installer/ffmpeg and @ffprobe-installer/ffprobe, and specify the ffmpegPath and ffprobePath properties in the options object.

---

Usage:

$3

Typescript:

`ts
import Transcoder from 'hls-transcoder'

async function transcodeVideo() {
const transcoder = new Transcoder([input-video.mp4/.mov/.avi/etc]`${__dirname}/output)

transcoder.on('error', (err) => {
console.error(err)
})

try {
const hlsPath = await transcoder.transcode()
console.log('Successfully Transcoded Video')
} catch (err) {
console.log(err)
}
}

transcodeVideo()
``

_OR_

Use @ffmpeg-installer/ffmpeg and @ffprobe-installer/ffprobe to use precompiled binaries of ffmpeg and ffprobe without having to install on your system.

Typescript:

`ts
import Transcoder from 'hls-transcoder'
import ffmpeg from '@ffmpeg-installer/ffmpeg'
import ffprobe from '@ffprobe-installer/ffprobe'

async function transcodeVideo() {
const transcoder = new Transcoder([input-video.mp4/.mov/.avi/etc]`${__dirname}/output, {
ffmpegPath: ffmpeg.path,
ffprobePath: ffprobe.path
})

transcoder.on('error', (err) => {
console.error(err)
})

try {
const hlsPath = await transcoder.transcode()
console.log('Successfully Transcoded Video')
} catch (err) {
console.log(err)
}
}

transcodeVideo()
``

Documentation:

$3


When creating a new instance of the Transcoder class, you can supply a third parameter options as an object which will override the default behaviour / settings of hls-transcoder. The possible options and their default values are as follows:

- allowUpscaling
- Description: When set to false renditions will only be transcoded if the original video is the same resolution or higher than that of the rendition being transcoded. When set to true
- Default: false
- Type: boolean | undefined
- ffmpegPath
- Description: Allows specifying which PATH hls-transcoder should use when invoking an ffmpeg child_process
- Default: ffmpeg
- Type: string | undefined
- ffprobePath
- Description: Allows specifying which PATH hls-transcoder should use when invoking an ffprobe child_process
- Default: ffprobe
- Type: string | undefined
- renditions
- Description: The various resolutions and bitrates hls-transcoder will use when transcoding video files
- Default: See default renditions
- Type: RenditionOptions | undefined

$3

The Transcoder class extends EventEmitter and will emit the following events:

- 'error'
- 'stderr'
- 'progress'
- 'end'

'error' - transcoding errors

`ts
transcoder.on('error', (err) => {
console.error(err)
})
`

'stderr' - information ffmpeg sends via the command line

`ts
transcoder.on('stderr', (data) => {
console.log(data)
})
`

'progress' - transcoding progress information

`ts
transcoder.on('progress', (progress) => {
console.log(progress)
})
`

The progress event is emitted everytime ffmpeg reports progress information. The progress object contains the following keys:

- frame: total processed frame count
- fps: framerate at which FFmpeg is currenlty processing

'end' - information about ffmpegs exit status

`ts
transcoder.on('end', (data) => {
console.log(data)
})
``

---

Ongoing TODOS:

- ~~Progress Bar~~
- Add option for outputPath param per Rendition
- Add option for Renditions per Resolution
- Fix ffmpeg stderr and stdout processing / parsing
- Currently in progress
- Test and/or handle .ts file name overflows
- ie. '1080p_0.ts' where number of ts segments > 10
- Figured out, default behavior is to just keep adding numbers, ie 11, 12, 13 - so this shouldn't be an issue unless there's a use case where a program is expecting the filenames to match a specfic pattern like that
- Create dir automatically if doesn't exist?
- Should do this, right now it fails silently if output dir doesn't exist
- Option to enable / disable overwrite?
- Invalid dimensions for renditions appear to fail silently