I am trying to loop audio from my Icecast server 24/7.

I have seen examples where people talk about storing their audio files on the EC2 instance or in an S3 bucket.

Do I also need a source client running on my EC2 Instance to be able to stream audio to the server? Or is there a way to play static files from Icecast?

CodePudding user response：

Icecast and SHOUTcast servers work by passing a live audio stream from a source on to the users. You need something to produce a single audio stream in realtime from those source files.

The flow looks something like this:

Basically, you'll need to do everything you would in a normal radio studio, but automated. You'll stream the files from your bucket, play them to a raw audio stream, send that stream to your encoder to be compressed with the codec, and then sent to your streaming servers for distribution.

You can't simply push your audio files as-is to the Icecast server, for a few reasons:

• Stream must be realtime
  The server doesn't really know or care about the timing of the stream. It takes the data its given and sends that off to the client. Therefore, if you push data faster than realtime, the server will attempt to deliver it to the client at this faster rate. Some clients will attempt to buffer this fast stream, but most will put backpressure on the stream, causing the TCP window to close, causing the client to eventually get far enough behind that the server drops the connection.

• Consistent format is required
  Chances are, your source files have varying sample rate, channel count, and even codec. Most clients are unable to take a change in sample rate or channel count mid-stream. I don't know of any client that supports a codec change mid-stream. (Theoretically possible with Ogg and Matroska/WebM, but yeah... not worth messing with.)

• Stream should be free of ID3 tags and other file format cruft
  If you simply PUT your files directly to your Icecast server, the output stream will contain more than just the audio data. At a minimum, you'd want to remove all that. Depending on your container format, you'll need to deal with timestamps as well.

Solutions

There are a handful of ways to solve this:

• Radio automation software
  Many folks simply run something like RadioDJ on cloud-based servers. If you already have a radio station that uses automation, this might be a good solution. It can be expensive though, and not as flexible. You could even go as low as VLC or something for playout, but then you wouldn't have music transitions and what not.

• Custom playout script (recommended)
  I use a browser engine, such as Chromium, and script my channels with normal JavaScript. From there, I take the output stream and pass it off to FFmpeg to encode and send to the streaming servers. This works really well, as I can do all my work in a language everybody knows, and I have easy access to data on cloud-hosted services. I can use the Web Audio API to mix and blend audio based on what's happening in realtime. As an alternative, there is Liquidsoap, but I do not recommend it these days as its language is difficult to deal with and it is not as flexible as a browser engine.