Shoutcast (DNAS) is known as the dominant audio streaming technology of the day. Shoutcast streams MP3 compressed audio instead of RealAudio's proprietary codecs. By combining high bitrates and better compression, higher quality audio streaming was possible with the MP3 codec & created an ecosystem where Shoutcast could serve internet radio streams; and Winamp could play those streams. With the latest release of Shoutcast (2.6), in January 2019, no longer supports AAC streaming. It is unclear whether the removal of this feature is intentional or just a bug.
Icecast was released in late 1999 as an open-source, created as an alternative to patent-encumbered streaming audio technologies of the day, including RealAudio and Shoutcast. In 2004, Icecast 2 brought improved metadata support, compatibility with Shoutcast clients, and more advanced configuration options, which were features that lead to widespread adoption in the internet radio community.
In 2012, a modified version of Icecast had been launched named Icecast-KH. The launch's objective is to overhaul some of the internals and multithreaded performance and add some experimental features like listener authentication. Over the years, this branch has served as a testbed for new Icecast features. As a result, Icecast-KH has become the defacto Icecast server used by most streaming hosting companies.
Codecs
The exact list of codecs that are supported by Icecast and Shoutcast is somewhat nebulous. For example, the Icecast homepage says "Ogg (Vorbis and Theora), Opus, WebM and MP3", without mentioning AAC at all, which is one of the most popular codecs today. Similarly, the Shoutcast homepage doesn't mention any codecs beyond MP3 and AAC ("up to 320 kbps").
We had performed test, to find out which codecs do Icecast and Shoutcast actually supports:
|
Codecs |
Icecast 2.4.4 | Icecast-KH 2.4.0-kh10 | Shoutcast v2.5.5.733 | Shoutcast v2.6.0.750 |
| MP3 | Yes | Yes | Yes | Yes |
| AAC | Yes | Yes | Yes | No |
| HE-AAC v1 | Yes | Yes | Yes | No |
| AAC+ (HE-AAC v2) | Yes | Yes | Yes | No |
| Ogg Vorbis | Yes | Yes | No | No |
| Ogg FLAC | Yes | Yes | No | No |
| Ogg Opus | Yes | Yes | No | No |
Features
Icecast and Shoutcast are very similar feature-wise, but some differences are depending on the use case:
- Directory listing: Many broadcasters choose Shoutcast because they want to have their stream advertised on the Shoutcast.com directory. Icecast has a similar guide, though it has lower visibility. However, there are dozens of stream directories on the web that you can submit your radio stream to for free, including TuneIn (the largest by far), so we don't recommend basis your decision of this feature.
- Flexible configuration: Icecast-KH is the most flexible streaming services when it comes to design. Certain features like wildcard mounts allow you to specify specific rules that apply to all mounts and are useful if you need to implement extra features based on this, such as geo-blocking.
- SSL / TLS / HTTPS Streams: Icecast and Icecast-KH both natively support HTTPS, but Shoutcast does not. However, it's a common practice for HTTPS to be wrapped around HTTP via a second web server or "reverse proxy", so some stream hosting companies can still provide HTTPS streaming for Shoutcast.
- Listener statistics: None of these streaming servers provides listener statistics other than the current listener count for each stream. Your stream hosting provider usually provides more advanced listener analytics, so Icecast vs. Shoutcast's statistics capabilities are less relevant.
Performance
To get a rough idea of Icecast and Shoutcast's performance, we ran a simple benchmark where we measured the average CPU usage of each server over 60 seconds, with 1000 listeners connected to a single 64 kbps MP3 source, using HTTP.
