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MPEG Surround Audio Coding Standard

Finally the technologies from Coding Technologies, Philips, Fraunhofer IIS and Agere were merged by MPEG for formalizing the new perceptual coding of 5.1 multichannel sound into the, so called, Reference Model 0 (RM0). In July 2005 MPEG and ISO approved this standard. You can find a lot in info about this technology in the official Tutorial on MPEG Surround Audio Coding.

MPEG Surround coding can be viewed as an enhancement of known techniques, such as a more flexible method of joint stereo coding, a generalization of MPEG Parametric Stereo already used in 3GPP rel6 (aacPlus v2) but for 5.1ch or 7.1ch sources or an extension of Binaural Cue Coding (BCC).

MPEG Surround exploits inter-channel differences in level, phase and coherence to capture the spatial image of a multi-channel audio signal relative to a transmitted downmix signal. It encodes each of these cues separately taking account of their distinctive characteristics such that the cues and the transmitted signal can be decoded to synthesize a high quality multi-channel representation allowing higher compression than separate channel coding. The downmix signal is a stereo track for high quality 5.1ch or 7.1ch coding or a mono track for 2ch or medium quality 5.1ch coding.

The MPEG Surround encoding process is agnostic to the compression algorithm used for the transmitted channels; it could be any of a number of high-performance compression algorithms such as MPEG-1 Layer III, MPEG-4 AAC or MPEG-4 High Efficiency AAC, or it could even be PCM.

You can test something very close the MPEG Surround using MP3 as the basic carrier. This technology from Fraunhofer is called MP3 Surround and it provides transparent 5.1ch compression at 192Kbps. An encoder and a MP3 Surround player is provided for free for non-comercial use.

This technology is backward and forward compatible and you can play the file or stream with a legacy player without the multichannel part.


MPEG Surround Audio Coding Standard

Reply #2
and more...

Those links are very old as you said but all of them are related to MP3 Surround. Please read the title of the topic and the main content of the post, I am talking about the MPEG Surround standard approval from July 2005. The FhG proposal was mentioned because it is the only testeable encoder.

The news is that the surround proposals from FhG/Agere and CT/Philips were not accepted, that leaves FhG MP3 Surround out with its commercial partner Divxnetworks. I have put this post about MPEG Surround because I think it can be relevant for developers who could be focusing in a dead end codec like MP3 Surround since the MPEG approved standard has more quality than the FhG proposal.

It will be a mess if both codecs are going to be used...

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