streaming-mp3-websockets-webaudio

Just because something is not designed for it, does not mean that it should be done. This is an example of how to stream MP3 files to a browser using WebSockets, and then playing them back using the WebAudio API. The server only supports one active client and can only server one file (provided at start as a command line argument). Also, the server assumes that the mp3 file constains and ID3v2.3 tag, without an extension header.

The server is written for nodejs and requires binaryjs. The client uses the webkit WebAudio-implementation, and has only been tested in Chrome and iOS6. Both client and server are written in CoffeeScript, so that is required in order to "compile".

If it had not been for one (current?) issue, this would have been a great alternative for audio streaming. Currently, the playback is a bit choppy, which I am unsure how to fix. The MP3 frame scheduling algorithm, which uses the continously updated context.currentTime, should be able to schedule frames directly after one another. However, for example, the timers in WebAudio all have a resolution of a second, which might not provide enough granularity.

Suggestions, improvements and comments are more than welcome.

How to install and run

1. Compile server and client using coffeescript. For example,

   coffee -c mp3_reader.coffee && coffee -c mp3_client.coffee

2. Start the server, provide an mp3 file as the first command line argument. For example,

   nodejs mp3_reader.js test.mp3

3. Open webaudio-test.html. Make sure that mp3_client.js is in the same folder.