NationMaster - Encyclopedia: Dolby Pro Logic

Dolby Pro Logic is a surround sound processing technology designed to decode soundtracks encoded with Dolby Surround. Dolby Surround Stereo was originally developed by Dolby Laboratories in 1976 for analog cinema sound systems. The format was adapted for home use in 1986 as Dolby Surround which was then replaced by the newer and improved Pro Logic system. However, the term "Dolby Surround" is still used to describe the encoding technology or matrix-encoded soundtrack, whereas Pro Logic refers to the decoding technology/processor. It is the home theater version of the Dolby Stereo technology used in movie cinemas in the 1970s and 80s. Image File history File links Prologic. ... Multichannel audio is the name for a variety of techniques for expanding and enriching the sound of audio playback by recording additional sound channels that can be reproduced on additional speakers. ... Sign for Dolby Surround Dolby Surround was the earliest consumer version of Dolbys multichannel analog film sound format Dolby Analog SR (Spectral Recording). ... Dolby Laboratories, Incorporated (Dolby Labs) is a company specializing in audio compression and reproduction. ... Year 1976 Pick up sticks(MCMLXXVI) was a leap year starting on Thursday (link will display full calendar) of the Gregorian calendar. ... Year 1986 (MCMLXXXVI) was a common year starting on Wednesday (link displays 1986 Gregorian calendar). ... Sign for Dolby Surround Dolby Surround was the earliest consumer version of Dolbys multichannel analog film sound format Dolby Analog SR (Spectral Recording). ...

Dolby Surround/Pro Logic is based on basic Matrix technology. When a Dolby Surround soundtrack is created, four channels of sound are matrix-encoded into an ordinary stereo (two channel) sound track by using phase shift techniques. A Pro Logic decoder/processor "unfolds" the sound into the original 4.0 surround—left and right, center, and a single limited frequency-range mono rear channel—while systems lacking the decoder play back the audio as standard Stereo. In sound recording, a matrix can refer to a disc in the early stages of processing a record for mass production; see mastering and pressing process discussion at gramophone record. ... Label for 2. ... This article is about a portion of a periodic process. ...

Although Dolby Surround was introduced as an analog format, all Dolby Digital decoders incorporate a digitally implemented Dolby Surround Pro Logic decoder for digital stereo signals that carry matrix-encoded Dolby Surround.

1 Dolby Pro Logic II
2 Dolby Pro Logic IIx
3 Software Encoding
4 Pro Logic Vs. Dolby Surround
5 Dolby Surround At A Glance
6 Dolby Encoding Matrices
7 See also
8 External links

Dolby Pro Logic II

In 2000, Dolby introduced Dolby Pro Logic II (DPL II), an improved implementation of Dolby Pro Logic. DPL II processes any high quality stereo signal source into "5.1"—five separate full frequency channels (left, center, right, left surround and right surround) plus one low-frequency-effects (deep bass) channel. Dolby Pro Logic II also decodes 5.1 channels from stereo signals encoded in traditional four-channel Dolby Surround. DPL II implements greatly enhanced steering compared to DPL, and as a result, offers an exceptionally stable sound field that simulates 5.1 channel surround sound to a much more accurate degree than the original Pro Logic. Image File history File links Dolbypl2. ...

Because of the limited nature of the original DPL, many consumer electronics manufactures introduced their own processing circuitry, such as the "Jazz", "Hall", and "Stadium" modes found on most common home audio receivers. DPL II forgoes this type of processing and replaces it with simple servo (negative feedback) circuits used to derive five channels. In addition to five full range playback channels, Pro Logic II introduced a Music mode which would not add any processing to the left and right channels, but will still extract a centre channel and two surround channels, providing a net effect of a wider center channel.

The Pro Logic II system also features a mode designed specifically for video gaming, and it is frequently used in game titles for Sony's PlayStation 2, Microsoft's Xbox, Xbox 360, Nintendo's GameCube and just recently the Wii as an alternative to digital technologies like Dolby Digital. â€œComputer and video gamesâ€ redirects here. ... The two versions of the PS2 with an Eye Toy camera The PlayStation 2 (PS2) (Japanese: プレイステーション2) is Sonys second video game console, after the PlayStation. ... Xbox and a Controller S The Xbox is Microsofts game console, released on November 15, 2001. ... Xbox 360 is Microsofts successor to their Xbox video game console, previously referred to during development as Project Xenon. The console is expected to be released in November 2005 in the U.S., Europe, and Japan. ... The Nintendo GameCube , GCN) is Nintendos fourth home video game console, belonging to the sixth generation era. ... The Wii (pronounced as the pronoun we, IPA: ) is the fifth home video game console released by Nintendo. ... Dolby Digital is the marketing name for a series of lossy audio compression technologies by Dolby Laboratories. ...

Dolby Pro Logic IIx

A newer Dolby Pro Logic IIx system is also now available, which can take stereo and Dolby Surround (sometimes called Dolby Stereo Surround) source material and up-convert it to 6.1, or 7.1 channel surround sound. Image File history File links L1_g_dolbyprologic2x. ...

Software Encoding

The liba52 decoder library for AC3 and A52 digital sound optionally exports stereo sound compatible with Dolby Surround and Pro Logic. [1] Sign for Dolby Surround Dolby Surround was the earliest consumer version of Dolbys multichannel analog film sound format Dolby Analog SR (Spectral Recording). ...

The Handbrake software for MacOS X is capable of downmixing Dolby Digital AC-3 5.1 to Stereo for Dolby Pro Logic I & II for surround playback. [2] Handbrakes logo HandBrake is open source, GPL licensed, multithreaded, cross-platform software that can decrypt and convert a DVD into a MPEG-4 video file in . ...

Minnetonka Audio SurCode software allows several commercial software packages to downmix multichannel audio to a Pro Logic 2 stereo signal.

Pro Logic Vs. Dolby Surround

Dolby Surround is the encoding counterpart to Dolby Pro Logic's decoding technology, but early home implementations of Dolby Surround decoding went by the name Dolby Surround which can cause some confusion. Dolby Surround and Dolby Pro Logic decoders are similar in principle, as both use matrix technology to extract extra channels from stereo-encoded audio. However, Pro Logic uses advanced algorithms, superior to the earlier home Dolby Surround system and similar to the original cinema Dolby Stereo processors, in order to not only extract the extra channels, but to also improve steering and discreteness between the channels. Image File history File links Download high-resolution version (1027x538, 81 KB) Dolby Surround Logo This is a logo of an organization, item, or event, and is protected by copyright and/or trademark. ... Image File history File links Prologic. ... Sign for Dolby Surround Dolby Surround was the earliest consumer version of Dolbys multichannel analog film sound format Dolby Analog SR (Spectral Recording). ...

Dolby Surround At A Glance

DeCoder	EnCoder	Year	Description	Channels
	Dolby Stereo	1975	Cinema use.	FL FR with C and RearMono matrixed
	Dolby SR	1986	Cinema use.	FL FR with C and RearMono matrixed
	Dolby Surround	1986	First Home use. Analog.	FL FR and RearMono matrixed
Dolby Pro Logic		> 1986	Improved Dolby Surround. Upmix Stereo to Surround 4.0.	FL FR with C and RearMono matrixed
Dolby Pro Logic II		2000	Improved Dolby Pro Logic. Upmix Mono(in Matrix mode) or Stereo to Surround 5.1 in either Matrix, Movie, Music, or Game mode.	FL FR C SL SR SUB
Dolby Pro Logic IIx			Upmix Stereo or Surround 5.1 to 6.1 or 7.1 in either Movie, Music, or Game mode.	FL FR C SL SR SUB and RearMono(x2)
Jazz, Hall & Stadium			Extra Decoders implemented by manufacturers. These add effects like echo and delay to change sound.
Dolby Digital	Adaptive Transform Coder 3 (AC3)	1992 Film 1995 Laser Disc	Discrete channel encoder/decoder. Pro Logic Decoder can be used for downmixed stereo inputs.	FL FR C SL SR SUB
Dolby Digital EX/Dolby Digital Surround EX		1999	6.1 or 7.1 (5.1 with Center Rear matrixed onto SL & SR)	FL FR C SL SR SUB RearMono(x1 or 2x)
	Dolby Digital Plus		High bitrate. Currently uses 7.1 channels with support for more.
	Dolby TrueHD		Lossless encoder for High Definition Video Sound. Eight full-range channels of 24-bit/96 kHz. Higher Bitrate than DD-Plus.
	Dolby Digital Live		On the Fly 5.1 encoder for Games.

Dolby Encoding Matrices

Dolby Surround	Left	Right	Center	Surround
Left Total	$1$	$0$	$frac{sqrt 2}{2}$	$j frac{sqrt 2}{2}$
Right Total	0	1	$frac{sqrt 2}{2}$	$k frac{sqrt 2}{2}$

j = +90° phase-shift, k = -90° phase-shift

Dolby Pro Logic	Left	Right	Center	Rear Left	Rear Right
Left Total	$1$	$0$	$frac{sqrt 2}{2}$	$j frac{sqrt 2}{2}$	$j frac{sqrt 2}{2}$
Right Total	$0$	$1$	$frac{sqrt 2}{2}$	$k frac{sqrt 2}{2}$	$k frac{sqrt 2}{2}$

j = +90° phase-shift, k = -90° phase-shift

Dolby Pro Logic II	Left	Right	Center	Rear Left	Rear Right
Left Total	$1$	$0$	$frac{sqrt 2}{2}$	$j sqrt frac{2}{3}$	$j sqrt frac{1}{3}$
Right Total	$0$	$1$	$frac{sqrt 2}{2}$	$k sqrt frac{1}{3}$	$k sqrt frac{2}{3}$

j = +90° phase-shift, k = -90° phase-shift

External links

Category: Film sound production

Results from FactBites:

Dolby Pro Logic - Wikipedia, the free encyclopedia (576 words)
	Dolby Surround was originally developed by Dolby Laboratories in 1976 for analog cinema sound systems as Dolby Analog SR (Spectral Recording).
	Dolby Surround is the encoding counterpart to Dolby Pro Logic's decoding technology, but early home implementations of Dolby Surround decoding went by the name Dolby Surround which can cause some confusion.
	Dolby Surround and Dolby Pro Logic decoders are almost identical in practice, as both use Matrix technology to extract extra channels from stereo-encoded audio.

Dolby Pro Logic - definition of Dolby Pro Logic in Encyclopedia (370 words)
	Dolby Pro Logic is an analog surround sound system developed by Dolby Laboratories, Inc. in 1986 for domestic use, based on their 1976 cinema system, Dolby Stereo.
	The Pro Logic system split the sound between four channels: left and right, center, and a limited-range mono rear channel which was split again between two speakers to enhance ambience.
	Pro Logic II is basically a redesigned version of Pro Logic, adding the low frequency effects (.1) channel and stereo surround channels to the encoded information, giving it full-range control (as opposed to Pro Logic's limited range) over the 5.1 channels used by most home theatre systems nowadays.

More results at FactBites »

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Contents

Dolby Pro Logic II GA_googleFillSlot("encyclopedia_square");

Dolby Pro Logic IIx

Software Encoding

Pro Logic Vs. Dolby Surround

Dolby Surround At A Glance

Dolby Encoding Matrices

See also

External links

Dolby Pro Logic II