EP0540329A2
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EP
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Method for storing a multichannel audio signal on a compact disc
Assignee: Nokia Technologies Oy
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Filing: 1992-10-29
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Granted: —
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Expires: 2012-10-29
Abstract
Abstract On a known compact disc, in which the information in digital form consists of left-channel and right-channel audio samples and of user data, it is possible to store a multichannel, for example surround sound, audio signal so that the multichannel audio signal is matrized into a first audio signal (L) and a second audio signal (R), for each of which there is calculated a masking threshold below which sounds are not audible to the human ear. The portion below the masking threshold is substituted by bits of a multichannel audio signal converted into a bit stream. All the control data required for extracting the signals containing multichannel information from the first and second audio signals are recorded as part of the user data of the CD, in its subcode words.
Inventors
- 👤 Juha Kuusama
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-26 06:39
CPC Classifications
H; H04; H04H; H04H20/00; H04H20/86; H04H20/88; G; G11; G11B; G11B20/00; G11B20/00992; G11B20/10; G11B20/10527; G11B20/12; G11B20/1217; G11B20/1251; G11B27/00; G11B27/10; G11B27/19; G11B27/28; G11B27/30; G11B27/3027; G11B27/3063; H04B; H04B1/00; H04B1/66; H04B1/665; G11B2020/10537; G11B2020/10592; G11B2020/10601
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
232 words
A method for storing a multichannel (A1, A2...An) audio signal on a compact disc, wherein the information in digital form is made up of the audio samples of the left channel and the right channel and of the user data which the reproducing equipment will need for arranging the audio samples into a stereo signal, and in which method the multichannel audio signal (A1, A2...An) is coded so that a bit stream is obtained, a first audio signal (L) and a second audio signal (R) are formed from the multichannel audio signal, there being calculated for each of them a masking threshold below which sounds are not audible to the human ear, and the bits of the said bit stream are substituted for those bits in the first and second audio signals which remain below the masking threshold, whereby a converted first audio signal (L′) and a converted second audio signal (R′) are obtained, characterized in that - all the control data required for extracting the bits of the said bit stream from the first and second audio signals are collected, - the converted first audio signal (L′) and the converted second audio signal (R′) are stored as the audio samples of the left channel and the right channel of the CD, - the collected control data are stored as part of the user data of the CD, in its subcode words.
Claim 2
Dependent Claim
34 words
A method according to Claim 1, characterized in that also that part of the bit stream which cannot be combined with the first and the second audio signals is combined with the control data.
Claim 3
Dependent Claim
47 words
A method according to Claim 2, characterized in that the format of the multichannel audio signal is 3/2, which means that it has a left channel (L), a right channel (R) and a center channel (C), as well as two surround channels (SR, SL) on the sides.
Claim 4
Independent Claim
32 words
A method according to Claims 1 and 3, characterized in that the first audio signal contains the left channel (L) information and the second audio signal contains the right channel (R) information.
Claim 5
Dependent Claim
196 words
A compact disc the digital-form information on which is made up of audio samples of the left channel and the right channel and of user data required by the reproducing equipment for arranging the audio samples into an audio signal, characterized in that - the audio samples of the first channel (L′) are made up of the first-channel (L) samples of a stereo sound formed from a multichannel audio signal (A1, A2...An), in which samples those bits which are below the masking threshold have been substituted by bits of a multichannel audio signal coded into a bit stream - the audio samples of the second channel (R′) are made up of the second-channel (R) samples of a stereo sound formed from a multichannel audio signal (A1, A2...An), in which samples those bits which are below the masking threshold have been substituted by bits of the multichannel audio signal coded into a bit stream, - all the control data required for extracting the bits of the bit stream from the audio samples of the first and the second channels (L′ and R′) and for reconstructing the original multichannel audio signal are incorporated into the user data subcoding.
Claim 6
Dependent Claim
48 words
A compact disc according to Claim 6, characterized in that the user data subcoding also includes that portion of the bit stream which it has not been possible to place below the masking threshold of the audio samples of the first channel (L) and the second channel (R).
References Cited (Backward Citations)
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