Implementation of an HLS (HTTP Live Streaming) server with pure Node.js
$ git clone https://github.com/andresmunozit/node-http-live-streaming-hls-server
$ npm install
To run the development environment:
$ npm run dev
Into the application directory, create the following directory tree:
/video
/media_name1
video.ts
/media_name2
video.ts
The name of the folder will determine the name of the media streaming. The video must be renamed to video.ts. The video must be in .ts format.
Into VLC or any other media player that supports HLS, use the .m3u8 path:
http://localhost:3000/media_name1.m3u8
Then click play and see the HLS stream reproducing.
If you want to download the .m3u8 playlist, go to the browser and hit http://localhost:3000/yourMediaName.m3u8.
HLS is a media streaming protocol based on HTTP. Instead of sending a "continous" stream of video data, the client requests sequentially an specific segment of the entire media (audio or video), based in a .m3u8 playlist.
There are two types of playlists, the master playlist and the media playlist.
The master playlist contains all the available nested playlists for the specified media. Those playlist can contain the same multimedia content, in different qualities, and includes other metadata, as resolution, codecs, etc., that the client will use depending on the bandwitdth available and other client specific factors. The following is an example of a master playlist:
#EXTM3U
#EXT-X-VERSION:5
#EXT-X-MEDIA:TYPE=AUDIO,GROUP-ID="audio",NAME="English stereo",LANGUAGE="en",AUTOSELECT=YES,URI="f08e80da-bf1d-4e3d-8899-f0f6155f6efa_audio_1_stereo_128000.m3u8"
#EXT-X-STREAM-INF:BANDWIDTH=628000,CODECS="avc1.42c00d,mp4a.40.2",RESOLUTION=320x180,AUDIO="audio"
f08e80da-bf1d-4e3d-8899-f0f6155f6efa_video_180_250000.m3u8
#EXT-X-STREAM-INF:BANDWIDTH=928000,CODECS="avc1.42c00d,mp4a.40.2",RESOLUTION=480x270,AUDIO="audio"
f08e80da-bf1d-4e3d-8899-f0f6155f6efa_video_270_400000.m3u8
#EXT-X-STREAM-INF:BANDWIDTH=1728000,CODECS="avc1.42c00d,mp4a.40.2",RESOLUTION=640x360,AUDIO="audio"
f08e80da-bf1d-4e3d-8899-f0f6155f6efa_video_360_800000.m3u8
Once the client has selected an stream from the master playlist, then it requests the specified .m3u8 media playlist. The media playlist contains direct links to the actual multimedia content, divided in ordered segments, which duration in seconds is specified in the playlist.
#EXTM3U
#EXT-X-VERSION:3
#EXT-X-MEDIA-SEQUENCE:0
#EXT-X-TARGETDURATION:4
#EXTINF:4.0
../video/180_250000/hls/segment_0.ts
#EXTINF:4.0
../video/180_250000/hls/segment_1.ts
#EXTINF:4.0
../video/180_250000/hls/segment_2.ts
#EXTINF:4.0
../video/180_250000/hls/segment_3.ts
#EXTINF:4.0
../video/180_250000/hls/segment_4.ts
#EXTINF:4.0
../video/180_250000/hls/segment_5.ts
#EXTINF:4.0
../video/180_250000/hls/segment_6.ts
#EXTINF:4.0
../video/180_250000/hls/segment_7.ts
A video client that supports HLS, will sequentially download the content of each video segment specified in the media playlist.
.ts video files contains flat video data. It allows to divide the entire video content in independent segments, that are reproducible, without the needing of metadata like other video formats (.mp4 for example).
This is an experimental implementation based on Node.js http, fs and path APIs.
One .m3u8 media playlist is generated by each media content in the video directory. This is an example of a .m3u8 playlist generated for an example media called city:
Media location:
./video
/city
/video.ts
Playlist:
#EXTM3U
#EXT-X-MEDIA-SEQUENCE:0
#EXT-X-TARGETDURATION:1.8
#EXTINF:1.8,
city/video/seq-0.ts
#EXTINF:1.8,
city/video/seq-1.ts
#EXTINF:1.8,
city/video/seq-2.ts
#EXTINF:1.8,
city/video/seq-3.ts
#EXTINF:1.8,
city/video/seq-4.ts
#EXTINF:1.8,
city/video/seq-5.ts
#EXTINF:1.8,
city/video/seq-6.ts
#EXTINF:1.8,
city/video/seq-7.ts
#EXTINF:1.8,
city/video/seq-8.ts
#EXTINF:1.8,
city/video/seq-9.ts
#EXTINF:1.8,
city/video/seq-10.ts
#EXT-X-ENDLIST
The following diagram is provided to understand how it works. Take into account that for clarity, pseudo code is being used:
There are three constants that can be defined in the top of the main app.js file:
PORT: The listening port fot the HTTP server
SEGMENT_SIZE: The size in bytes of each read stream video segment
VIDEO_EXT: The file extension of the video data
The video location folder is not configurable at the moment.
This is an exploratory project no longer mantained. A new version is being developed using Express.js, and will include other features like uoload and transform video to .ts format and generate different qualities or use AWS S3.