Technical Specifications

Table of Contents

System Requirements

Linux:

  • CentOS: CentOS 7 or later.
  • Ubuntu / Debian: Ubuntu 14.04 or later
  • Other Linux distributions: glibc 2.27 or later
  • A 64-bit x86 CPU supporting SSE2 and SSE3.

Windows:

  • Windows 7 or later. Windows 10 or 11 recommended.
  • 64-bit Windows recommended, but 32-bit is compatible
  • Intel Core 2 Duo or AMD FX-4100 greater (2008 or newer)
  • 2 GB RAM
  • 200 MB free disk space

Streaming Audio Encoder Compatibility

Rocket Streaming Audio Server is compatible with all Icecast2-compatible encoders. RSAS supports both SOURCE and PUT verbs.

Our recommended encoder is Rocket Broadcaster, but RSAS is also compatible with:

  • SAM Broadcaster
  • Sonifex PS-SEND Pro Audio Streamers
  • Barix Instreamer
  • Mixxx
  • RadioDJ
  • Station Playlist
  • and many more...

Supported Codecs

Streaming Compatibility by Codec

Format Bitrates (kbps) Samplerates (Hz) Channels
MP3 16, 32, 48, 56, 64, 96, 128, 192, 256, 320 11025, 22050, 44100, 48000, 96000 Mono, Stereo
AAC (AAC-LC) 16, 32, 48, 56, 64, 96, 128, 192, 256, 320 11025, 22050, 44100, 48000, 96000 Mono, Stereo
HE-AAC v1 16, 32, 48, 56, 64, 96, 128, 192, 256, 320 22050, 44100, 48000, 96000 Mono, Stereo
HE-AAC v2 (AAC+) 16, 32, 48, 56, 64, 96, 128, 192, 256, 320 22050, 44100, 48000, 96000 Stereo
Ogg Vorbis 16, 32, 48, 56, 64, 96, 128, 192, 256, 320 11025, 22050, 44100, 48000, 96000 Mono, Stereo
Ogg Opus 16, 32, 48, 56, 64, 96, 128, 192, 256, 320 8000, 12000, 16000, 24000, 48000 Mono, Stereo
Ogg FLAC (Lossless) Avg. ~1500 kbps 11025, 22050, 44100, 48000, 96000 Mono, Stereo

Feature Compatibility by Codec

Codec Metadata Support Relaying Fallbacks HLS
MP3 Yes, in-stream (ICY) Yes Yes Yes
AAC (AAC-LC) Yes, in-stream (ICY) Yes Yes Yes
HE-AAC v1 Yes, in-stream (ICY) Yes Yes Yes
HE-AAC v2 (AAC+) Yes, in-stream (ICY) Yes Yes Yes
Ogg Vorbis Yes, in-stream (ICY) Yes Yes* No
Ogg Opus Yes, in-stream (ICY) Yes Yes* No
Ogg FLAC (Lossless) Yes, in-stream (ICY) Yes Yes* No

* Seamless fallbacks for Ogg streams depend on the player's ability to resync, and has a low compatibility. We recommend using MP3 and AAC streams if you require seamless fallbacks (no listeners dropped), as RSAS has perfect frame-synced fallback transitions for these codecs, which should be compatible with every player. For more information, see the Configuration section on Fallbacks.

Relaying

RSAS supports relaying HTTP and HTTPS streams from:

  • Icecast 2.3, 2.4.x
  • Icecast-KH
  • Shoutcast 1
  • Shoutcast 2.5
  • Shoutcast 2.6
  • AIS 8.x
  • Nimble Streamer
  • Wowza
  • RSAS

HLS streams can be relayed from RSAS only. (HTTP streams can be converted to HLS on-the-fly though.)

HLS

RSAS dynamically converts traditional HTTP streams to HLS. HLS segments use Packed Audio (AAC ADTS or MP3 only).

For more information, see HLS Technical Details.

HTTP

RSAS supports HTTP/1.1 including Keep-Alive (persistent connections) and the Range header for static files.

The maximum HTTP request header size is 4 KB and this can be customized.

HTTPS / TLS

RSAS supports HTTPS using TLS 1.2 and 1.3. The default cipher suite and all configuration options are documented here.

RSAS is fully compatible with free LetsEncrypt SSL/TLS certificates.

Reverse Proxy Compatibility

RSAS is known to play nicely with haproxy, and likely works well with nginx too. The X-Forwarded-For header is supported by RSAS so that client IPs are recorded correctly in the access.log.

Although RSAS supports TLS / HTTPS itself, using haproxy in front of RSAS can be used as an alternative approach to providing TLS / HTTPS streams. RSAS can serve static files, so it plays nicely with certbot / LetsEncrypt too.

Proxy Servers

Use of an HTTP proxy server for outbound HTTP(S) requests made by RSAS is supported.