Paris, France – At the Audio
Engineering Society (AES) Expo details were revealed on the nature of MPEG
Surround, a new audio standard that after its final draft publication in July
could knock Dolby from its spot as the defacto standard for multichannel audio
compression.
The big thing going for MPEG Surround is that
it is supposed to allow allows broadcasters and content providers to
high-quality surround sound to MP3 files or other MPEG audio streams for
Internet Protocol TV, mobile entertainment and Internet, without setting aside
additional channels for transmission.
Based on a highly efficient parametric coding
algorithm, it is able to reduce bit-rate requirements for high-quality
multichannel audio compression, and maintain backward compatibility with
existing stereo equipment.
The technology can transform mono or stereo
audio signals compressed in MP3, MPEG-4 Advanced Audio Codec or MPEG-4 HE-AAC
into high-quality multichannel surround audio with only a slight increase in
data rate, compared to the existing Dolby spec, which can operate only when
severe transmission-channel bandwidth limitations are imposed.
Unlike the 5.1-channel Dolby Digital, which
requires proprietary multichannel audio compression separate from MP3 and other
MPEG audio codecs, MPEG Surrond can be implemented by simply replacing a stereo
encoder with a surround encoder, with no other changes in the existing audio
streaming infrastructure.
MPEG Surround, because of its minimal
infrastructure re-engineering brings a number of high end audio capabilities
down the cost cure, such as the ability to transmit a compact set of parameters
representing the spatial image of the original surround-sound signal along with
an automatic mono or stereo downmix as well as a separate optional,
hand-optimized downmix signal.
As this spatial side information is sent in an
auxiliary data field, a receiving device's MPEG Surround decoder can expands the
transmitted downmix signal into a high-quality multichannel output.
In a low end receiver, with no MPEG Surround
decoder, this information in the spatial parameters is ignored and it decodes
the stream as stereo. MPEG Surround's surround-enhancement data rate is scalable
from 3 to 32 kbits/second.
Because it does not require broadcasters or
content owners to send (or store) both stereo and multichannel versions of
audio, the new specification, when finally available will be rapidly adopted
with potential applications in digital radio systems and Internet streaming, as
well as multichannel services for mobile-TV broadcasts.
For more information, go to
www.aes.org.
For more information about topics, issues and technologies mentioned in this story go to the flashing icon in the upper left corner on
this page or go to the iAppliance Web Views page and call up the associatively-linked Java/XML-based Web map of the iApplianceWeb site.
Enter the appropriate key word, product or company name to list instantly every news and product story, product review and product database entry relating to the topic since the beginning of the 2002.
|
|