Extended Adaptive Multi-Rate – Wideband (AMR-WB+) is an audio

codec A codec is a device or computer program that encodes or decodes a data stream or signal. ''Codec'' is a portmanteau of coder/decoder. In electronic communications, an endec is a device that acts as both an encoder and a decoder on a signal or ...

that extends

AMR-WB Adaptive Multi-Rate Wideband (AMR-WB) is a patented wideband speech audio coding standard developed based on Adaptive Multi-Rate encoding, using a similar methodology to algebraic code-excited linear prediction (ACELP). AMR-WB provides improved ...

. It adds support for stereo signals and higher sampling rates. Another main improvement is the use of transform coding (transform coded excitation – TCX) additionally to

ACELP Algebraic code-excited linear prediction (ACELP) is a speech coding algorithm in which a limited set of pulses is distributed as excitation to a linear prediction filter. It is a linear predictive coding (LPC) algorithm that is based on the cod ...

. This greatly improves the generic audio coding. Automatic switching between transform coding and ACELP provides both good speech and audio quality with moderate bit rates. As AMR-WB operates at internal sampling rate 12.8 kHz, AMR-WB+ also supports various internal sampling frequencies ranges from 12.8 kHz to 38.4 kHz. AMR-WB uses 16 kHz sampling frequency with a resolution of 14 bits left justified in a 16-bit word. AMR-WB+ uses 16/24/32/48 kHz sampling frequencies with a resolution of 16 bits in a 16-bit word.3GPP TS 26.290; Audio codec processing functions; Extended Adaptive Multi-Rate – Wideband (AMR-WB+) codec; Transcoding functions
Page 10, Retrieved on 2009-07-08 3GPP originally developed the AMR-WB+ audio codec for streaming and messaging services in Global System for Mobile communications (

GSM The Global System for Mobile Communications (GSM) is a standard developed by the European Telecommunications Standards Institute (ETSI) to describe the protocols for second-generation ( 2G) digital cellular networks used by mobile devices such ...

) and Third Generation ( 3G) cellular systems. Its primary target applications are Packet-Switched Streaming service ( PSS), Multimedia Messaging Service (MMS) and Multimedia Broadcast and Multicast Service (MBMS). File storage of AMR-WB+ encoded audio is specified within the 3GP container format, 3GPP-defined ISO-based multimedia file format defined in 3GPP TS 26.244. The AMR-WB+ codec has a wide bit-rate range, from 5.2 to 48 kbit/s. Mono rates are scalable from 5.2 to 36 kbit/s, and stereo rates are scalable from 6.2 to 48 kbit/s, reproducing bandwidth up to 20 kHz (approaching CD quality). Moreover, it provides backward compatibility with AMR wideband.

Software support

In September 2005, VoiceAge Corporation announced availability of AMR-WB+ decoder in Helix DNA Client.

Licensing and patent issues

AMR-WB+ compression incorporate several

patent A patent is a type of intellectual property that gives its owner the legal right to exclude others from making, using, or selling an invention for a limited period of time in exchange for publishing an enabling disclosure of the invention."A ...

s of

Nokia Corporation Nokia Corporation (natively Nokia Oyj, referred to as Nokia) is a Finnish multinational telecommunications, information technology, and consumer electronics corporation, established in 1865. Nokia's main headquarters are in Espoo, Finland, i ...

, Telefonaktiebolaget L. M. Ericsson and VoiceAge Corporation. VoiceAge Corporation is the ''License Administrator'' for the AMR and AMR-WB+

patent pool In patent law, a patent pool is a consortium of at least two companies agreeing to cross-license patents relating to a particular technology. The creation of a patent pool can save patentees and licensees time and money, and, in case of blocking ...

s. VoiceAge also accepts submission of patents for determination of their possible essentiality to these standards. The initial fee for applications using "real-time channels" with AMR-WB+ is $6,500. Minimum annual royalty shall be $10,000, excluding the initial fee in year 1 of the license agreement. AMR-WB+ monaural decoder in a category of personal computer products is licensed for free. Stereo AMR-WB+ decoder for personal computer products is licensed for $0.30.

References

External links

3GPP codecs specifications; 3G and beyond / GSM, 26 series

* – RTP Payload Format for the Extended Adaptive Multi-Rate Wideband (AMR-WB+) Audio Codec * – The Codecs Parameter for "Bucket" Media Types {{DEFAULTSORT:Extended Adaptive Multi-Rate - Wideband Audio codecs Speech codecs

Software support

Licensing and patent issues

See also

References

External links