Developed jointly by Ericsson, Nokia and VoiceAge, the AMR-WB+ (Extended Adaptive Multi-Rate Wideband) speech and audio codec is the 3GPP-recommended hi-fi audio codec for MMS, PSS and MBMS services over GSM and WCDMA networks. It is also recommended for DVB-H applications.

AMR-WB+ scales to cover the full audio spectrum and uses high-efficiency parametric stereo (HE-PS) to maintain high-fidelity stereo image reproduction at even the lowest bit rates and excellent quality at higher rates.

In characterization tests carried out by third parties for the ETSI/3GPP standards organizations, at bit rates of 14 and 24 kbps for mono and 18 and 24 kbps for stereo, AMR-WB+ outperformed MPEG-4 AAC in all tests and outperformed MPEG-4 HE-AAC in seven of eight tests.

Coded AMR-WB+ media can be encapsulated in 3GPP (.3gp, i.e., MMS) or MPEG-4 (.mp4) file formats and used along the entire delivery chain in multimedia applications. The RTP payload format for AMR-WB+ has been defined by IETF, supporting interleaving for robust streaming and forward error correction (FEC) for enhanced robustness.

Emerging end-to-end digital communication systems enable the use of full audio coding in a large and varied collection of applications for mobile environments. Applications include streaming services for music, news and sports as well as multimedia messaging services for person-to-person and business-to-person communications.

Now a breakthrough technology — Extended AMR Wideband (AMR-WB+) — addresses mixed speech and audio content at low bit rates. As an extension of the AMR-WB standard, the AMR-WB+ audio codec combines advanced audio coding technology with unrivaled speech coding technology, allowing service providers to deliver consistent high-quality audio while making efficient use of their transmission capacity.

In addition to delivering rich, natural-sounding speech like AMR-WB, AMR-WB+ delivers high-quality music, voice-over-music and voice-between-music, making it perfectly suited to low-bit-rate mixed-content audio applications such as multimedia messaging; 3GPP Packet-Switched Streaming (PSS), Multimedia Broadcast/Multimedia Service (MBMS) and IMS Messaging and Presence services; streaming audio over the internet; audio storage and playback; digital radio broadcasting; archiving and distribution of narrative content and network-based language-learning applications.


Encoded bandwidth

~ 50-19200 Hz


3GPP 2004

Coding type

Hybrid ACELP®/TCX (Algebraic Code Excited Linear Prediction/Transform-Coded Excitation)

Bit rate

Mono: 6-36 kbps
Stereo: 7-48 kbps

Delay (ms):
Frame size

80 x 25.6/Fs where Fs is the internal sampling frequency in kHz
10 x 25.6/Fs


For any content, equal or better performance than any other codec available in 3GPP

Speech quality better than AMR-WB and HE-AAC

High-quality music, better than HE-AAC at low bit rates (<= 18 kbps)

Decoder Complexity:

Below 24 kbps:
Mono: 8 WMOPS
Stereo: 24 WMOPS

RAM: 13 Kwords
ROM: 20 Kwords


  • Server-based streaming (PSS): music and other audio content in mono and stereo, movies, video clips, news programming, sports events, audio books, commercial advertisements, access to multimedia information systems, interactive gaming, “infotainment”

  • Download services: hi-fi ringtones, music, video clips, movie trailers, audio books

  • Multimedia Messaging Services (MMS): person-to-person messaging, application-to-person messaging, instant messaging

  • Multimedia Broadcast/Multicast Service (MBMS): live TV, radio programming, multi-player interactive gaming, commercial advertisements

  • Media players, media servers, media gateways

  • Content creation tools

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