MICONNECT L1 -LESSON 10 – UNDERSTANDING THE AUDIO

Primary Pathway for Audio Playback

MiConnect handles audio playback in two primary ways:

Local playback: Each Gateway/Node stores and plays MP3/WAV files directly.
Multicast streaming: Audio can be broadcast site-wide (PA announcements, music, events).

Unlike SIP-only systems, MiConnect is not locked into phone-call audio quality. It was built for tones, music, and high-fidelity alerts.

Play stored MP3/WAV locally for bells, tones, announcements, and pre-recorded messages. – This is achieved through API commands
Multicast PA streaming across the site for live announcements or centralised music playback. – This is achieved through multicast listeners
Maintain redundancy: alerts and tones are always triggered locally, so even if multicast fails, safety alerts still fire. – This is because once it is triggered it waits for another command or until it finished its programmed command

SIP (Session Initiation Protocol) was designed for voice over IP (VoIP).
Common codecs:
- G.711 – 64 kbps PCM, narrowband (8 kHz). “Phone line quality”.
- G.729 – 8 kbps highly compressed, but very lossy.
Limitation: Optimised for speech, not music. Tones and music sound “tinny” or clipped.

Lossy compression designed for music distribution.
Bitrates typically 128–320 kbps.
Saves storage space, but throws away some audio data.
On a MiConnect Node, MP3 is fine for bells, tones, or music playback because it’s stored locally.

What is GStreamer?
- A multimedia framework for real-time streaming with efficient compression.
- Allows encoding that reduces bandwidth without noticeable audio quality loss.
Why it matters:
- With GStreamer, MiConnect can multicast high-quality audio (like music) across a site without clogging the network.
- Alerts and tones are still triggered locally → redundancy remains intact.
Planned Impact:
- Streaming good-quality background music from a MiConnect Console’s inbuilt music player.
- While alerts (lockdown, evac, tones) still fire locally for reliability.
- This will create a big improvement over TOA RM SIP multicast.

TOA RM Console
- Uses SIP codecs for multicast PA streaming.
- Quality is acceptable for speech and tones, but music sounds compressed.
MiConnect Console (in development)
- Uses GStreamer for multicast audio.
- Higher fidelity (music-friendly) while still optimising bandwidth.
- Provides an inbuilt music player for centralised streaming.
- Keeps local redundancy for tones/alerts.

MiConnect doesn’t rely on SIP audio codecs alone.
Always high-quality (MP3/WAV local playback, GStreamer multicast).
Redundant by design: local playback ensures tones/alerts never depend on central streaming.

Schools and enterprises needed:

Consistent bells and tones that cut through noisy environments.
The ability to stream music across campuses without horrible SIP compression.
Confidence in redundancy: even if multicast streaming fails, tones/alerts still fire locally.

MiConnect delivers on all three.

👉 Think of it like music on your phone:

SIP = a compressed phone call recording — tinny and narrow.
MP3 = your Spotify offline playlist — good quality, reasonable size.
WAV = your studio master recording — huge file, but flawless.
GStreamer multicast = like Spotify HiFi streaming — great sound, smaller bandwidth, works everywhere.