Dolby ProLogic II : du neuf avec du vieux

Dolby vient d’annoncer la mise au point d’un nouveau procédé de décodage appelé "Dolby ProLogic II". Selon leurs dires, ce procédé de décodage permet à tous programmes codés en Dolby Surround de bénéficier d’une ambiance "quasiment" 5.1.
A l’origine, ce procédé a été développé pour conférer aux sources musicales stéréo - qui ont encore de beaux jours devant elles - une ambiance Surround naturelle et crédible. Le résultat de ces recherches est un décodeur capable de traiter une très large gamme de programmes, films et musiques.

Pour information, vous trouverez ci-dessous la News officielle de Dolby (English only...).

Dolby Announces Pro Logic II Decoding
San Francisco, June 20, 2000 - Dolby Laboratories announced today the introduction of Pro Logic II, the next generation of Dolby Surround Pro Logic decoding technology. Pro Logic II brings exciting new features and advanced performance for decoding the many thousands of existing Dolby Surround programs, making them sound more like a discrete Dolby Digital 5.1-channel version than ever before.
The world is rapidly transitioning to digital delivery formats like DVD, and digital television (DTV), satellite and cable, all of which offer Dolby Digital 5.1 audio capability. The music industry is on the verge of transitioning from stereo to 5.1-channel sound with the new DVD-Audio format. Consumers enthusiastically demand 5.1-channel sound in new programs of all kinds. But vast numbers of programs already exist in stereo and Dolby Surround, and many more will continue to arrive in years to come. Pro Logic II lets consumers enjoy these programs with a convincing "5.1-like" presentation.
Pro Logic II is able to decode the thousands of existing Dolby Surround movies and TV shows already on the shelf, compatibly, and with enhanced image stability. The improvements in decoding techniques mean that the discreteness of the sound field elements are better-preserved in the decoding process than was possible with the now universally standard Pro Logic technology, developed in the mid 80s.
"The technology in Pro Logic II is the first fundamentally new approach in matrix decoder design since the basic design which is still at the core of every other active matrix surround decoder," said Roger Dressler, Director of Technology Strategy for Dolby Laboratories. "Pro Logic II was designed from the outset to convert conventional stereo music recordings, which will be with us for some time to come, to a natural, believable surround experience. The result is a decoder that can handle a wide range of movie and music program material with equal skill. Dolby is proud to be handling the licensing and technical support of this exciting new technology."
This new system was invented by Jim Fosgate, one of the most prolific developers of surround decoding technologies since the quadraphonic era of the late 1960s. Mr. Fosgate said, "I have spent the past 25 years figuring out how to expose the hidden information in standard two-channel stereo recordings, both new and old. This breakthrough in matrix decoding technology allows users to enjoy all their existing two-channel programs, whether Dolby Surround encoded or not, with an enhanced level of spatiality and directionality."
Pro Logic II also incorporates special features for controlling the overall spatial dimensionality and frontal soundfield imaging that are particularly suited for autosound applications. A standard four-channel Pro Logic decoding mode is also included in the technology package.
Dolby Surround Pro Logic II decoding can be implemented economically in either analog and digital circuitry, making it ideal for use in all traditional home theater products and in a range of new "music surround" products.