AirCodec  ·  Audio

Pick the codec on the connection, not in a config file.

Pull the menu down and go, or load a saved preset. Opus from a trickle to transparent, linear PCM for an STL with the bandwidth, and the telephone-grade pair for whatever only speaks those. On a Direct link the return can run a different codec entirely.

Bit rate, one connection Opus6 k – 510 k · mono or stereo · FEC MP3MPEG audio over RTP Linear PCMuncompressed G.722 · G.711telephone grade

What is in the menu

Sample rate follows the codec — 48 kHz for the broadcast codecs. Bit rate and channel count are on the connection form, and combinations a station uses again and again are saved as presets in their own Settings tab.

CodecRangeWhy you would pick it
Opus 6 k – 510 k
mono / stereo		 The one to default to on a path you do not control. Forward error correction is set per connection, and it holds together on a link that is losing packets.
MP3 MPEG audio
over RTP		 For units that offer it and nothing better.
Linear PCM uncompressed
48 kHz		 An STL with the bandwidth to spare. No codec in the chain at all — nothing to argue about later.
G.722 7 kHz
wideband		 Anything that only speaks telephone grade, when you still want more than a phone line.
G.711 µ-law / A-law narrowband The lowest common denominator. It will always connect.

Direct links carry a separate receive-side codec, so a 256 k stereo send can come back as a 64 k mono return without a second connection.

What forward error correction actually does

A codec does not get to choose a good network. Packets go missing on cellular, on hotel wifi, on a congested backhaul at five past the hour. FEC sends a small spare copy of each slice inside the next packet, so when one goes missing the far end rebuilds it instead of leaving a hole.

Sender one slice per packet Receiver nothing heard Lossy network Each packet carries a spare copy Rebuilt in place, from that copy Nothing is asked for again, and nothing waits — the gap never happens.

One slice goes missing in the middle. The copy riding behind it fills the slot, and the receiver never hears a gap.

With it offThe far end has nothing to put in the gap. Depending on the decoder you get a click, a chirp or a short silence — and on a path losing one percent, that is several an hour, every hour.
It costs bit rateThe spare copies ride inside the same stream, so a connection at 10 % FEC spends about a tenth of its budget insuring itself. Wasted on a clean private circuit; the cheapest insurance you will buy all season on a cellular remote.
Set per directionThe send and the return rarely cross the same network. A Direct link can run heavier correction on the leg that needs it and leave the other alone.
Direct adds a second netOn a Direct link a missing packet can also be asked for again and retransmitted, when there is time in the buffer to wait for it. FEC handles what cannot wait; retransmission catches what can.
On screenThe readout says 10 % or off — the plain quantity, not the name of a mechanism.

How to pick a number. Watch the LOSS cell on the readouts grid for a few minutes on the path you are actually going to use. Zero, and you can leave FEC off. A fraction of a percent, and 10 % will cover it. Anything that moves around — a cellular remote, a venue's guest wifi — start at 20 % and watch whether RECOVERED starts counting.

AirCodec

Not sure what the far end will take?

Send us the make and model and the path it has to cross, and we will tell you which codec and bit rate to start from — and whether you want FEC on it.

Ask about AirCodec See pricing

$499.99 per codec · run up to five on one PC

More on AirCodec

Connecting other codecs Security Compatibility Stay on air On screen SNMP and monitoring Pricing