Radio hosting glossary: the terms in two lines

AAC: Audio codec that sounds better than MP3 at the same bitrate. Its HE-AAC variant goes further at low bitrates. Every current phone and browser plays it.
Audio processor: A chain of compression, limiting and EQ that makes a station sound "big" and even. FM always has one; a stream only if it is added before the encoder or the encoder includes it.
Auto-podcast: A service that records the air, cuts it by show according to the schedule and publishes each show as an on-demand episode.
AutoDJ: An audio library on the provider's server that plays music and ads when the encoder isn't sending, and lets you schedule hours with nobody in the studio.
Bitrate: Amount of compressed audio data per second, in kbps. 128 kbps AAC is the sensible standard for music radio in 2026.
Buffer: Audio the player stores ahead so it doesn't cut out when the connection wobbles. It causes the few seconds of delay behind live.
Catch-up: A recording of the last hours or days on air that lets listeners rewind live or play a show later.
CDN / delivery network: Servers spread geographically that replicate the signal so each listener gets it from the nearest one, and a single failure doesn't take the station off air.
Codec: The way audio is compressed: MP3, AAC, HE-AAC, Opus. It defines how a given bitrate sounds.
Concurrent listeners: How many people are connected to the stream at the same time. The unit most plans are sold in: choose the plan by the peak.
Encoder: The program or device in the studio that takes the audio from the desk, compresses it and sends it to the streaming server.
HLS: HTTP Live Streaming: splits audio or video into segments of a few seconds published over HTTP. Easy to distribute across server networks; more latency than Icecast.
Icecast: Free streaming server for audio that delivers a continuous flow over HTTP with ICY metadata. One of the two classics of internet radio.
ICY metadata: The metadata protocol of Icecast and Shoutcast: it carries the song title and artist inside the stream.
Ingest: The point in the provider's network where the encoder's signal enters. Ideally close to the studio.
Latency: Time between what happens in the studio and what the listener hears or sees: seconds on Icecast, 10 to 30 on classic HLS.
Listener hours (TLH): Total listener hours: one listener for one hour equals one. Some hosts sell monthly TLH allowances instead of a concurrent limit.
Mount point: An address inside an Icecast server that the encoder connects to and listeners play from, such as /live. A server can have several.
MP3: The classic audio codec, compatible with everything. Acceptable at 128 kbps; below that, compression shows more than with AAC.
Multi-bitrate (ABR): In video, the same signal published at several resolutions at once; the player picks according to the viewer's connection.
PWA / wrapped website: A website installable on the phone that is sometimes sold as an "app". It is not in the stores, nor in Android Auto or CarPlay.
RTMP: Classic protocol for sending video from the encoder to the ingest. Every broadcasting program supports it.
Shoutcast: The other classic audio server for radio. Compatible with almost everything; some old devices and directories expect its v1 URLs.
SLA: A service-availability commitment, as a percentage. 99.9% allows almost 9 hours of downtime a year; 99.998%, about 10 minutes. It counts when published, measured and backed by compensation.
SRT: Modern protocol for sending video to the ingest over unstable connections: it recovers lost packets and keeps latency under control.
SSL / HTTPS: Encryption of the connection. The stream and the player must be on HTTPS: browsers block insecure audio inside secure pages.
Transfer: Total data your listeners use in a month (GB or TB). Some providers cap it or bill it separately; others include it with no cap.
Transmisor: INOVANEX's own encoder for Windows and Mac, with audio processing included and linking by code.

Radio hosting glossary: the terms in two lines

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