What bitrate should an internet radio station use?

The short answer

Whether your listeners hear a difference between these rates depends on the music, their headphones and their ears. We do not publish a listening test, so this guide does not tell you that one rate sounds better. It gives you what can be checked: what each rate costs in data, in upload speed and in storage. There is a simple way to judge the sound yourself further down.

How much data does a stream use?

A bitrate is bits per second. To get bytes per hour, multiply by 3,600 seconds and divide by 8 bits per byte:

MB per listener-hour = kbps × 3,600 ÷ 8 ÷ 1,000

At 128 kbps that is 128 × 3,600 ÷ 8 = 57,600 kilobytes, or 57.6 MB, for each hour one person listens. At 320 kbps it is 144 MB. The figures on this page use decimal units (1 GB = 1,000 MB). A phone or a computer that counts in 1,024s shows slightly smaller numbers for the same bytes. They count the audio only: the network adds a little on top.

Listener-hours add up. Ten people listening for two hours is 20 listener-hours: at 128 kbps that is 1,152 MB of audio leaving the server, and at 320 kbps it is 2.9 GB. Hosts that cap monthly transfer count this traffic, so the same formula tells you whether a transfer allowance fits your station.

What upload speed does the broadcaster need?

One stream at the encoder's bitrate, however many people are listening. Your encoder sends a single copy to the stream server, and the server hands a copy to every listener. A 320 kbps show needs 0.32 Mbit/s of upload from you, whether one person is listening or five hundred.

That rate has to be available for the whole show, not on average. Anything else on the same connection (a video call, a cloud backup, a game update on another computer) takes from the same upload. Our suggestion is to have at least twice the stream's bitrate free, to test your upload speed at the hour you broadcast rather than at a quiet moment, and to use a wired connection instead of Wi-Fi. If you broadcast from a phone hotspot, a two-hour show at 320 kbps sends 288 MB, and at 128 kbps it sends 115.2 MB.

Why do listeners' mobile data plans matter?

Many people listen on a phone, away from Wi-Fi, and every hour comes out of their monthly allowance. Take someone who listens for an hour each working day, about 22 hours a month. That is about 1.3 GB a month at 128 kbps, about 2.5 GB at 256 kbps and about 3.2 GB at 320 kbps. The worked example is arithmetic, not a measurement of real listeners.

So a higher bitrate is not free for your audience. If your listeners are mostly on mobile data, a lower rate asks less of them. If they mostly listen at a desk or on home Wi-Fi, the data matters less.

How many hours of music fit in your storage?

Hours per GB = 1,000 ÷ MB per hour. At 320 kbps, 1 GB holds about 6.9 hours. At 128 kbps it holds about 17.4 hours. For an AutoDJ library, what matters is the bitrate of the files you store, which is not always the bitrate you broadcast. On MAWCast the two can differ, as the MAWCast section below explains.

Can you hear the difference between 128 and 320 kbps?

Test it with your own music rather than taking anyone's word for it:

1. Pick three tracks that sound like your station, including one with cymbals or a busy mix.
2. Export the same minute of each at 128, 192 and 320 kbps MP3 from the same source file.
3. Have someone else play them to you in random order, on the headphones or speakers your listeners are likely to use, and note which is which.

If you cannot tell them apart reliably, the lower rate saves your listeners data for nothing they would notice. Whichever rate you choose, start from the best source you have. An encoder cannot add back what an earlier stage lost, so a 128 kbps file re-encoded at 320 kbps is still a 128 kbps file in disguise.

What bitrate does MAWCast stream at?

MAWCast streams MP3 at a rate set by your plan, and it has two rates: one for live shows and one for AutoDJ.

Every listener receives the same stream at your plan's rate. There is no separate low-data stream for listeners to pick.

What if my encoder sends more than my plan's quality?

MAWCast accepts the connection and re-encodes the show to your plan's live quality on its way to air. It never refuses a broadcaster because of bitrate. A DJ who sends 320 kbps to a Starter station is heard at 128 kbps. Sending more does not improve what listeners hear. It only uses more of your upload. The same re-encoding works the other way: a show sent at a lower rate still reaches listeners at the plan's rate, so it does not save them data either. Set your encoder to your plan's live rate. Icecast hosting with MAWCast explains how any Icecast-compatible encoder connects.

What happens to the files I upload for AutoDJ?

You can upload MP3, WAV, OGG, FLAC and M4A. An MP3 is kept as you uploaded it. Any other format is converted to an MP3 at 320 kbps, which replaces the original, and AutoDJ plays it once the conversion has finished. When a track airs, AutoDJ re-encodes it to your plan's AutoDJ rate (128 kbps on Starter, 256 kbps on the other plans), whatever the file's own bitrate. The details are in supported formats, and AutoDJ covers the rotation itself.

This affects storage. A FLAC or WAV file is stored at 320 kbps, about 144 MB per hour. If you upload MP3s at your plan's AutoDJ rate instead, the same space holds more hours, and what listeners receive is the same, because the stream is at the AutoDJ rate either way. See storage and limits.

Which bitrate do you need, then?

If a live rate of 128 kbps and an AutoDJ rate of 128 kbps suit your listeners, Starter is enough. If you want live shows at 320 kbps, that starts with Air. The limits of each plan, including listeners at once and storage, are on pricing, and plans and limits explains what changes when you switch.

If you are still setting up, how to start an internet radio station covers the rest: music rights, hosting, AutoDJ and going live.

Create your station. The 3-day Starter trial needs a verified payment method.

Written by the MAWCast team.