Broadcasting Glossary

A comprehensive guide to technical terms used in radio streaming, broadcast infrastructure, and internet radio.

Audio & Streaming Formats

AAC (Advanced Audio Coding)

A lossy audio compression format that provides better sound quality than MP3 at the same bitrate. Commonly used for high-quality streaming, especially on mobile devices and Apple platforms.

MP3 (MPEG Audio Layer 3)

The most widely supported audio codec for streaming. Works on virtually all devices and players. Standard for internet radio broadcasting.

Opus

A modern, open-source audio codec designed for interactive real-time applications. Provides excellent quality at low bitrates. Increasingly popular for streaming.

Vorbis (Ogg Vorbis)

An open-source alternative to MP3 that offers better quality at lower bitrates. Used primarily with Icecast servers.

Bitrate

The amount of data transmitted per second, measured in kilobits per second (kbps). Higher bitrates mean better audio quality but require more bandwidth. Common streaming bitrates:

• 64 kbps: Speech/talk radio (acceptable quality)
• 128 kbps: Music streaming (good quality)
• 192 kbps: Music streaming (high quality)
• 320 kbps: Music streaming (maximum quality)

Streaming Protocols & Servers

Icecast

An open-source streaming media server that supports MP3, AAC, Opus, and Vorbis formats. Highly flexible and widely used for internet radio. Free to use.

SHOUTcast

A commercial streaming server developed by Nullsoft (later AOL, now Radionomy). Widely supported by directory services and players. Requires licensing for commercial use.

Mountpoint

A unique URL path on your streaming server where listeners connect. For example: http://stream.yourstation.com:8000/live
Each mountpoint can broadcast different content (e.g., /live for main stream, /mobile for mobile quality).

Stream URL

The complete address listeners use to connect to your radio stream. Format: http://your-server:port/mountpoint
Example: http://stream1.hippynet.co.uk:8000/yourstation

Port

A numerical identifier for network services. Streaming servers typically use ports like 8000, 8080, or custom ports to differentiate multiple streams on the same server.

Broadcast Infrastructure

Datacenter / Data Centre

A facility housing servers and networking equipment with redundant power, cooling, and internet connections. Professional hosting uses datacenters with 24/7 monitoring and physical security.

Redundancy

Backup systems that take over if primary systems fail. May include redundant servers, power supplies, network connections, or entire datacenters.

Uptime

The percentage of time a service is operational and accessible. Measured as a percentage:

• 99.9% uptime = ~8.7 hours downtime per year
• 99.99% uptime = ~52 minutes downtime per year

SLA (Service Level Agreement)

A contract defining guaranteed service levels, typically including uptime commitments and support response times. Premium services may include SLAs with financial penalties for failures.

Bandwidth

The amount of data that can be transmitted in a given time period. For streaming:

• Required bandwidth = (bitrate × number of listeners) / 8
• Example: 100 listeners at 128kbps = 1,600 kbps = 1.6 Mbps

CDN (Content Delivery Network)

A network of geographically distributed servers that cache and deliver content from the location nearest to the user, reducing latency.

Latency

The delay between your audio source and listener playback. Lower latency means listeners hear your broadcast closer to real-time. Typical streaming latency: 5-15 seconds.

Automation & Control

AutoDJ

Automated software that plays pre-uploaded music when you're not broadcasting live. Handles crossfading, playlist rotation, and continuous playback without manual intervention.

MediaCP

A web-based control panel for managing Icecast and SHOUTcast servers. Provides visual interface for uploading music, managing playlists, viewing statistics, and controlling streams without command-line access.

cPanel / Plesk / DirectAdmin

Web hosting control panels for managing websites, email, databases, and files. Not radio-specific, but often included with web hosting packages.

Encoder

Software that converts audio into a streaming format and sends it to your stream server. Examples:

• BUTT (Broadcast Using This Tool)
• RadioBOSS
• SAM Broadcaster
• Mixxx

Source

Your audio input to the streaming server. Could be:

• Live encoder from a studio
• AutoDJ playing scheduled content
• External relay from another stream

Technical Concepts

DNS (Domain Name System)

Translates human-readable domain names (yourstation.com) into IP addresses (123.45.67.89) that computers use to connect. Essential for making your stream accessible via easy-to-remember URLs.

IP Address

A numerical identifier for devices on a network. Format: 192.168.1.1 (IPv4) or 2001:0db8::1 (IPv6). Your streaming server has an IP address that listeners' players connect to.

Firewall

Security system that controls incoming and outgoing network traffic. Can block unauthorized access while allowing legitimate listener connections.

SSL/TLS Certificate

Encryption certificate that enables HTTPS (secure) connections. Increasingly required for embedding streams in websites, especially on mobile browsers.

Metadata

Information about the currently playing track, sent alongside the audio stream. Includes artist, title, and album. Displays in listeners' players and on your website player.

Transcoding

Converting audio from one format to another, or from one bitrate to another. Example: receiving 320kbps MP3 and broadcasting as both 320kbps and 128kbps for mobile listeners.

Listener Experience

Buffering

Pre-loading audio data to create a smooth playback experience even if network speed varies. Too little buffering causes stuttering; too much increases latency.

Stream Relay

A server that receives your stream and re-broadcasts it to listeners, distributing the load across multiple servers or geographic locations.

Listener Limit / Slot

The maximum number of simultaneous connections your streaming plan allows. Each connected listener uses one slot, regardless of how long they listen.

Peak Listeners

The highest number of simultaneous listeners during a given time period. Used to determine if you need to upgrade your plan.

Tuning In

When a listener connects to your stream. Also the name of a popular radio directory (TuneIn).

Specialized Services

AutoPod

Automatic podcast generation service that records your live radio stream and publishes episodes to podcast platforms. Also creates "listen again" / catch-up functionality for your website.

Listen Again / Catch-Up Radio

On-demand access to previously broadcast shows. Listeners can play back shows they missed. AutoPod automates this process.

Backup Transmitter Feed

A redundant stream that monitors your primary broadcast and automatically takes over if the primary feed fails. Essential for DAB and FM stations where off-air time means regulatory issues.

Silence Detection

Monitoring system that detects when your stream is broadcasting silence (dead air) and sends alerts. Can trigger automatic actions like switching to backup content.

Stream Monitoring

Automated systems that continuously check your stream is online, measure audio quality, verify metadata, and alert you to problems before listeners notice.

DAB & FM Radio Terms

DAB (Digital Audio Broadcasting)

Digital radio broadcast standard used in the UK and Europe. Requires constant audio feed to the transmitter. If the feed fails, the station goes off-air.

FM (Frequency Modulation)

Analog radio broadcasting method. Still widely used alongside DAB. Requires studio-to-transmitter link (STL).

STL (Studio-to-Transmitter Link)

The connection carrying audio from your studio to the broadcast transmitter. Can be physical cable, microwave link, or IP-based (internet). Backup STLs prevent off-air time.

Multiplex / MUX

A DAB multiplex bundles multiple radio stations into a single digital broadcast signal. Your station is one channel within the multiplex.

Ofcom

The UK's communications regulator. Licenses broadcast frequencies and enforces broadcasting standards. Off-air time can result in license violations.

Quality & Performance

Sample Rate

How many times per second audio is sampled when digitizing. CD quality is 44.1 kHz. Higher sample rates (48 kHz, 96 kHz) capture more detail but require more bandwidth.

Crossfade

Overlapping the end of one song with the beginning of the next to create smooth transitions without gaps of silence.

Normalization

Adjusting audio levels so all tracks play at consistent volume. Prevents some songs being too loud or too quiet.

Audio Processing

Compression, equalization, and level adjustments applied to audio before streaming. Ensures consistent, professional sound quality.

Business & Legal

GDPR (General Data Protection Regulation)

UK/EU data protection law requiring specific handling of personal data. Affects how you collect listener information and handle customer data.

Royalty Payments

Fees paid to rights holders for music broadcast. In the UK:

• PRS for Music: License for musical compositions
• PPL: License for sound recordings

Required for most music broadcasting, with different rates for commercial vs community stations.

Community Radio License

UK radio license for not-for-profit stations serving specific geographic communities. Subject to Ofcom regulation with specific content requirements.

White Label

Rebranding a service provider's infrastructure under your own brand name. Allows reselling services to your customers as if you provide them directly.

Software & Playout Systems

LibreTime

Open-source radio automation software for scheduling shows, managing playlists, and streaming to Icecast/SHOUTcast. Fork of Airtime, designed for community radio stations.

Airtime (Legacy)

Original open-source radio automation platform. Replaced by LibreTime for most users. Web-based interface for show scheduling and playlist management.

mAirList

Professional broadcast automation software for radio stations. Supports live assist, full automation, and voice tracking. Popular in European commercial radio.

RadioDJ

Free Windows-based radio automation software. Popular for internet stations. Supports playlists, voice tracking, and rotation management.

SAM Broadcaster

Commercial broadcast automation software with built-in encoder. All-in-one solution for station automation and streaming.

BUTT (Broadcast Using This Tool)

Free, cross-platform encoder for sending live audio to Icecast/SHOUTcast servers. Simple interface, reliable for live broadcasting.

Mixxx

Free, open-source DJ software with live broadcasting capabilities. Supports Icecast/SHOUTcast streaming directly from the mixer interface.

Liquidsoap

Advanced stream generator using a scripting language. Powerful for complex automation scenarios like scheduled show transitions and fallback content.

Audio Processing & Production

Compressor / Compression

Audio processing that reduces the dynamic range by making loud sounds quieter and quiet sounds louder. Creates more consistent audio levels and prevents clipping.

Limiter

Prevents audio from exceeding a maximum level, protecting against distortion. Essential for maintaining broadcast standards and preventing over-modulation.

EQ / Equalization

Adjusting the balance of frequency ranges (bass, midrange, treble) to shape the sound. Can compensate for poor recording quality or create signature station sound.

Stereo Tool

Professional audio processing software that provides comprehensive audio enhancement: multiband compression, stereo widening, bass enhancement, and broadcast-standard limiting.

AGC (Automatic Gain Control)

System that automatically adjusts audio levels to maintain consistent volume across different sources (music vs speech, different recordings, live presenters).

Clipping

Audio distortion that occurs when signal levels exceed maximum capacity. Sounds harsh and unprofessional. Prevented by proper limiting.

Jingle / Sweeper / Ident

Short audio elements used for station identification:

• Jingle: Musical station identification
• Sweeper: Quick station identification (often voice + music bed)
• Ident: Simple station name announcement

Bed / Music Bed

Background music played underneath voice content (like weather forecasts, news, or presenter links).

Voice Tracking

Pre-recording presenter links that play automatically between songs. Allows creating shows without being live. Also called "tracking" or "automation-assisted presenting".

Network & Connectivity

IPv4 vs IPv6

Internet Protocol versions. IPv4 uses addresses like 192.168.1.1, IPv6 uses longer addresses like 2001:0db8::1. Both work for streaming, IPv6 is newer and gradually replacing IPv4.

NAT (Network Address Translation)

Allows multiple devices on a private network to share a single public IP address. Can complicate incoming connections for encoders; port forwarding may be needed.

Port Forwarding

Configuring your router to direct incoming connections on a specific port to a device on your local network. Needed if encoding from behind a router/firewall.

VPN (Virtual Private Network)

Encrypted connection that routes your traffic through another server. Can be used to access geo-restricted services or secure remote broadcasting connections.

DDoS (Distributed Denial of Service)

Attack flooding a server with fake traffic to overwhelm it and knock it offline. Professional hosts use DDoS protection to filter malicious traffic.

Ping / Latency

The time it takes for data to travel between two points on a network. Lower ping = better for live streaming. Measured in milliseconds (ms).

Packet Loss

When data packets fail to reach their destination. Causes dropouts and stuttering in streams. Usually indicates network congestion or poor connection quality.

Jitter

Variation in packet arrival times. High jitter causes inconsistent streaming quality. Good networks have low, stable jitter.

Upstream / Upload Speed

Your internet connection's upload bandwidth. Critical for broadcasting — you need sufficient upstream to send your stream reliably. Asymmetric connections (ADSL) often have limited upload speed.

Playout & Scheduling

Playlist Rotation

System for scheduling music to prevent repetition and ensure variety. Types:

• Heavy Rotation: Frequently played current hits
• Medium Rotation: Regular playlist items
• Light Rotation: Occasional tracks, deeper cuts
• Specialty: Genre-specific or themed content

Clock / Format Clock

A template defining what content plays when. Example: "15 minutes music, 5 minutes news, 2 minutes commercials, repeat". Also called "hour clock" or "format wheel".

Dayparting

Scheduling different content for different times of day (breakfast show format in morning, specialist shows at night, automated music overnight).

Logs / Playout Log

Record of everything broadcast, including exact play times. Required for:

• Royalty reporting (PRS/PPL)
• Ofcom compliance
• Sponsor proof-of-performance

Segue

Transition between songs or show elements. Can be:

• Hard Segue: One track stops, next starts (no gap)
• Soft Segue: Crossfade between tracks
• Dead Air: Deliberate silence between elements

Audio Delivery & Players

HTML5 Player

Modern web-based audio player using HTML5 audio tags. Works on all modern browsers without plugins. Replaced Flash players.

M3U / PLS Playlist

File formats containing stream URLs. Used by media players to connect to your stream:

• M3U: Simple text file with stream URL
• PLS: INI-style format with additional metadata

Embed Code

HTML/JavaScript code allowing you to embed your stream player in websites. Usually provided by hosting control panel.

Radio Directory

Online catalog of radio stations where listeners discover new content:

• TuneIn: Largest global radio directory
• Radio Garden: Interactive globe interface
• Radioline: European radio aggregator

Aggregator

Service that collects multiple radio streams and makes them available through a single app or website. Examples: TuneIn, Radioline, myTuner.

Smart Speaker Integration

Compatibility with voice-activated speakers (Amazon Alexa, Google Home). Requires submission to respective directories and sometimes custom "skills" or "actions".

Live Broadcasting

Talkback / Comms

Communication system between studio and remote contributors or between studio and transmission. Not heard by listeners.

Cue / PFL (Pre-Fade Listen)

Monitoring a source before it goes on air. Allows presenter to check audio levels and content without listeners hearing.

Fader

Volume control on a mixing desk. "Fading up" brings audio on air, "fading down" removes it.

Mix-Minus

Audio feed sent to remote contributors containing everything except their own voice. Prevents echo/feedback during phone-ins or remote interviews.

Delay / Profanity Delay

7-15 second delay between live audio and broadcast, allowing offensive content to be censored before transmission. Required for phone-ins on regulated broadcast.

OB (Outside Broadcast)

Broadcasting from a location outside the main studio. Requires portable equipment and reliable connection back to station infrastructure.

Streaming Quality & Reliability

Buffer Underrun

When the player runs out of pre-loaded audio data, causing interruption. Usually indicates network congestion or insufficient bitrate.

Icecast Master/Slave

Icecast relay configuration where one server (master) feeds multiple servers (slaves) to distribute listener load geographically.

Fallback Stream / Fallback Mount

Alternative content that plays if your primary source disconnects. Prevents dead air during source failures.

Reconnect / Auto-Reconnect

Encoder feature that automatically re-establishes connection if dropped. Essential for reliable live broadcasting.

Kick / Force Disconnect

Manually disconnecting a source or listener from the server. Used to clear hung connections or remove unauthorized sources.

Broadcast Standards & Compliance

Loudness Standards

Broadcasting standards defining permitted audio levels:

• EBU R128: European broadcast loudness standard (-23 LUFS)
• ATSC A/85: US broadcast loudness standard

Community radio typically less regulated than commercial/DAB

LUFS (Loudness Units Full Scale)

Modern measurement of perceived loudness accounting for human hearing. Replaced peak measurement for broadcast standards.

Peak Level

Maximum instantaneous audio level. Measured in dBFS (decibels Full Scale). 0 dBFS is maximum digital level; going over causes clipping.

Licensing Requirements (UK)

Broadcasting music requires:

• PRS for Music: License for musical compositions
• PPL: License for sound recordings
• Ofcom Broadcast License: For DAB/FM transmission (not internet-only)

Content Quotas

Requirements for locally produced or specific language content. Ofcom community radio licenses often require percentage of local content.

Advanced Technical

RTMP (Real-Time Messaging Protocol)

Protocol originally developed for Flash streaming. Still used by some encoders and can be converted to Icecast/SHOUTcast formats.

HLS (HTTP Live Streaming)

Adaptive bitrate streaming protocol developed by Apple. Breaks stream into small chunks, allowing players to switch quality based on connection speed.

WebRTC (Web Real-Time Communication)

Technology enabling real-time audio/video communication in web browsers. Used for ultra-low-latency streaming (<1 second delay).

Codec

Software or hardware that encodes/decodes digital audio. Examples: MP3, AAC, Opus, Vorbis. Different codecs offer different quality/efficiency trade-offs.

Container Format

File format that holds encoded audio and metadata:

• MP3: Self-contained format
• OGG: Container for Vorbis or Opus
• MP4/M4A: Container for AAC

RDS (Radio Data System)

Data signal sent alongside FM broadcasts containing station name, song info, traffic alerts. Not applicable to internet streaming (metadata serves similar purpose).

Stereo vs Mono

• Stereo: Two-channel audio (left and right), creates spatial sound
• Mono: Single-channel audio, identical in both ears

Speech/talk often broadcast in mono to save bandwidth; music typically in stereo.

Joint Stereo

MP3 encoding technique that stores differences between left/right channels rather than full separate channels. More efficient for certain audio content.

Station Operations

Playlist / Rotation

Collection of music tracks scheduled for broadcast. Can be:

• Power Rotation: 20-50 tracks playing very frequently
• Current: 100-200 tracks, current chart music
• Recurrent: 200-500 tracks, recent hits no longer current
• Gold: 500+ tracks, classic library material

Music Scheduling Software

Programs that generate playlists following format clocks and rotation rules:

• Music Master
• Selector
• PowerGold
• Natural Music

Hot Clock

Visual representation of content scheduled each hour, showing music, commercials, news, weather segments in pie chart or clock format.

Stopset

A group of commercials or promotional announcements scheduled together. Common in commercial radio (e.g., "3-minute stopset on the hour").

Bed / Cart

Pre-produced audio elements ready to play:

• Bed: Music background for voice
• Cart: Any pre-recorded element (from old cart machine terminology)

Liner / Station Liner

Pre-recorded promotional announcement for the station or upcoming shows. "You're listening to Station X, coming up at 7..."

Common Acronyms

• kbps - Kilobits per second (bitrate measurement)
• Mbps - Megabits per second (bandwidth measurement)
• GB - Gigabyte (storage/transfer measurement, 1 GB = 1,024 MB)
• SSD - Solid State Drive (fast storage with no moving parts)
• NVMe - Non-Volatile Memory Express (very fast SSD technology)
• API - Application Programming Interface (allows software to interact programmatically)
• SSH - Secure Shell (encrypted remote server access)
• FTP - File Transfer Protocol (uploading files to servers)
• URL - Uniform Resource Locator (web address)
• MCR - Master Control Room (broadcast control center)
• PSB - Public Service Broadcaster (BBC, etc.)
• RAJAR - Radio Joint Audience Research (UK radio measurement)
• STL - Studio-to-Transmitter Link
• OB - Outside Broadcast
• TX - Transmission / Transmitter
• RX - Receive / Receiver
• UI - User Interface
• CLI - Command Line Interface
• GUI - Graphical User Interface
• HTTPS - Hypertext Transfer Protocol Secure (encrypted web)
• VM - Virtual Machine (virtualized server)
• TTL - Time To Live (cache duration)
• RAID - Redundant Array of Independent Disks (storage redundancy)
• UPS - Uninterruptible Power Supply (battery backup)

Hippynet-Specific Terms

MediaCP

The control panel we provide for managing your Icecast/SHOUTcast stream. Visual interface for uploading music, creating playlists, viewing statistics, and controlling your stream.

StreamMachine

Hippynet's geographically diverse streaming infrastructure designed for maximum uptime. Uses multiple cloud providers and availability zones to ensure your stream stays online even during infrastructure failures.

Infrastructure as Code

Our approach to server provisioning where configurations are defined in code, allowing rapid deployment of identical environments and quick recovery from failures.

Multi-Cloud Architecture

Our strategy of using multiple cloud providers (not relying on a single vendor) to ensure service continuity even if one provider has issues.

Availability Zone

Isolated datacenter within a cloud region. We deploy across multiple zones so if one has power/network issues, your stream continues from another.

Troubleshooting Terms

Dead Air / Silence

When no audio is broadcasting. Major issue for radio stations. Our silence detection systems alert you within seconds.

Buffering Issues

When listeners experience frequent pauses/stuttering. Causes:

• Insufficient bandwidth for bitrate
• Network congestion
• Server overload
• Listener's poor connection

Source Disconnected

When your encoder loses connection to the stream server. AutoDJ should kick in as fallback to prevent dead air.

403 Forbidden

Error when listener or source is blocked from connecting. Usually authentication failure or IP ban.

503 Service Unavailable

Server is online but can't accept connections (usually at listener capacity or temporarily overloaded).

Connection Timeout

Encoder or listener can't establish connection within time limit. Indicates network issues or incorrect stream URL/port.

Getting Help

Still confused by a term? Our broadcast engineers are available 24/7 to explain any technical concept in plain English.

Contact Support:

• Phone: +44 800 520 0073
• Email: [email protected]
• Submit Ticket: Client Area

Last Updated: November 2025

This glossary is maintained by Hippynet's broadcast engineers and updated as new technologies emerge.