How Internet Radio Works
A plain-language explanation of how internet radio streaming works: streams, codecs, metadata, and how players like Moodi.fm connect you to 50,000+ live stations.
Internet radio sounds like magic – thousands of live stations from every corner of the world, instantly available in your browser. Under the hood it is surprisingly simple. Here is how it actually works.
From transmitter to stream
Traditional FM radio broadcasts an analogue signal from a transmitter tower; your receiver tunes to a frequency and converts the signal back into sound. Internet radio replaces the tower with a streaming server. The station encodes its live audio into a digital format and pushes it to a server, which then sends a continuous stream of audio data to every connected listener.
When you press play on a station in Moodi.fm, your browser opens a connection to that station's stream URL and starts receiving audio packets. A few seconds of audio are kept in a buffer, so brief network hiccups don't interrupt playback. That is also why internet radio typically runs a few seconds behind the FM broadcast of the same station.
Codecs and quality
Stations compress their audio with a codec before sending it. The most common ones you will encounter:
- MP3 – the veteran. Universally supported, usually streamed at 128–320 kbit/s.
- AAC / AAC+ – more efficient than MP3; good quality at lower bitrates, popular with bandwidth-conscious stations.
- OGG Vorbis / Opus – open-source codecs, often used by community and independent stations.
A higher bitrate generally means better sound but more data usage. 128 kbit/s MP3 is roughly comparable to good FM reception; 256 kbit/s and above is close to CD quality for most ears.
Metadata: knowing what's playing
Most streams carry a small side channel of text data alongside the audio – usually the current artist and song title. Players read this metadata and show it on screen, which is how Moodi.fm can display what's playing on many stations and let you look up a track you just discovered.
Where the station list comes from
There is no central authority for internet radio – anyone can run a station. Directories solve the discovery problem. Moodi.fm uses the open-source, community-maintained Radio Browser database, which volunteers around the world keep up to date with stream URLs, genres, languages and countries. On top of that raw catalogue we add our own curation: mood collections, genre pages and trending lists that make 50,000+ stations actually browsable.
Why stations sometimes drop
Because every station runs its own infrastructure, reliability varies. A station may go offline for maintenance, change its stream URL, or limit the number of simultaneous listeners. When that happens, a player can only reconnect or suggest an alternative – it is part of the charm (and occasional frustration) of a decentralised medium.
Why the same station can behave differently
Internet radio is decentralized. Two listeners can open the same station from different countries and have different experiences because the broadcaster may use regional mirrors, geoblocking, advertising servers or capacity limits. A stream that works well in the morning can also struggle during a special event if many listeners connect at once.
That is why Moodi.fm treats reliability as part of discovery. A station entry is not just a name and logo; it is a live endpoint controlled by someone else. If one stream fails, the practical answer is often to reconnect, try a backup favorite or choose another station with a similar format.
What buffering really means
Buffering is a small safety margin. The player downloads a few seconds of audio ahead of playback so short network changes do not immediately interrupt the sound. Too little buffer causes dropouts; too much buffer increases delay. For live radio, a few seconds of delay is normal and usually worth it for smoother listening.
Metadata is separate from the audio itself. Some stations send artist and title updates accurately, some update late, and others send only the station slogan. Missing metadata does not mean the stream is broken; it usually means the broadcaster does not publish track details in a consistent format.
Why directories and players both matter
A directory such as Radio Browser solves the map problem: it collects stream URLs, names, countries, tags and technical details from many contributors. A player solves the listening problem: it turns that raw information into a usable experience, handles playback states, remembers favorites and makes it easier to recover when a stream fails. Moodi.fm sits in the second role while respecting that broadcasters and directory contributors remain the source of the live stream data.
When evaluating a radio player, this distinction is important: Moodi.fm is not pretending to own the broadcasts. It provides access, context and a listening interface around streams that already exist. Good behavior means clear attribution, realistic expectations and quick recovery when a broadcaster changes something.