jsmpeglive

jsmpeglive

An MPEG1 Video Decoder in JavaScript

jsmpeglive is a MPEG1 Live Video Decoder, written in JavaScript.

It receives a live stream, via WebSocket.

It is prepared to use any other Transport method available. It just needs to follow the same interface as the included built-in WebSocketClient.

This WebSocketClient has the logic to reconnect every 5 seconds

TODO: add some logarithmic/fibonacci/exponential back-off method

Setup

Run npm install and then npm start to start the HTTP and WebSockets server.

In an other terminal, Then, to start streaming, you can use a camera that provides a RTSP feed, or your own laptop

# Laptop Web cam feed
./start_ffmpeg_stream.sh /dev/video0

or

# Camera Feed
./start_ffmpeg_stream.sh "rtsp://192.168.1.54:554/axis-media/media.amp?videocodec=h264&resolution=640x480"

Building

To build, just run npm build

API

Constructor

var player = new jsmpeglive(uri[, options])

The uri argument accepts a WebSocket address for streaming playback.

The options argument to jsmpeglive() supports the following properties:

• benchmark whether to log benchmark results to the browser's console
• canvas the HTML Canvas element to use; jsmpeglive will create its own Canvas element if none is provided
• ondecodeframe a function that's called after every frame that's decoded and rendered to the canvas

Examples

The best example is just checking the source code. Feel free to review stream-example.html.

Note that you have to include both WebSocketClient and jsmpeglive

var player = new jsmpeglive('ws://localhost:8084/', {canvas:canvas});

Diferences between jsmpeglive and jsmpeg

The Transport layer was removed from the main jsmpeg decoding object. Also, as I didn't need recording, it was removed, as well as all the functions for playing local video files.

Limitations

• Only raw MPEG video streams are supported. The decoder hates Stream Packet Headers in between macroblocks.

You can use FFmpeg to encode videos in a suited format. Check start_ffmpeg_stream,sh, it has the parameters needed to crop the size to a multiple of 2, omit B-Frames and force a raw video stream.

Inspiration

It is based on the work of Dominic Szablewski's jsmpeg

jsmpeg is based on Java MPEG-1 Video Decoder and Player by Korandi Zoltan and inspired by MPEG Decoder in Java ME by Nokia.