Fraunhofer-Gesellschaft Zur Foerderung Der Angewandten Forschung E.V.

M2any Gmbh

Agere Systems Inc.

Other

Dolby Laboratories Licensing Corporation

Eric Allamanche

Juergen Herre

Oliver Hellmuth

Thorsten Kastner

Sascha Disch

Christof Faller

Jürgen Herre

Karlheinz Brandenburg

Christian Neubauer

Markus Cremer

Bernhard Grill

Nikolaus Rettelbach

Karsten Linzmeier

Juergen Koller

Niels Rump

Bernhard Froeba

In one embodiment, C input audio channels are encoded to generate E transmitted audio channel(s), where one or more cue codes are generated for two or more of the C input channels, and the C input channels are downmixed to generate the E transmitted channel(s), where C&#x3e;E&#x2267;1. One or more of the C input channels and the E transmitted channel(s) are analyzed to generate a flag indicating whether or not a decoder of the E transmitted channel(s) should perform envelope shaping during decoding of the E transmitted channel(s). In one implementation, envelope shaping adjusts a temporal envelope of a decoded channel generated by the decoder to substantially match a temporal envelope of a corresponding transmitted channel.

Diffuse sound shaping for BCC schemes and the like

An input audio signal having an input temporal envelope is converted into an output audio signal having an output temporal envelope. The input temporal envelope of the input audio signal is characterized. The input audio signal is processed to generate a processed audio signal, wherein the processing de-correlates the input audio signal. The processed audio signal is adjusted based on the characterized input temporal envelope to generate the output audio signal, wherein the output temporal envelope substantially matches the input temporal envelope.

Techniques for introducing information into a data stream first obtains the spectral values of the short-term spectrum of the audio signal. Separately, information to be introduced are combined with a spread sequence obtaining a spread information signal, whereupon a spectral representation of the spread information is generated, then weighted with an established psychoacoustic maskable noise energy to generate a weighted information signal, wherein energy of the introduced information is substantially equal to or below the psychoacoustic masking threshold. The weighted information signal and the spectral values of the short-term spectrum of the audio signal are then summed and afterwards processed again to obtain a processed data stream including audio information and information to be introduced. Because the information to be introduced are introduced without changing to the time domain, the block rastering underlying the short-term spectrum are not touched, thus introducing a watermark will not lead to tandem encoding effects.

Method and apparatus for introducing information into a data stream and method and apparatus for encoding an audio signal

For analyzing an information signal having a sequence of blocks of information units, wherein a plurality of consecutive blocks of the sequence of blocks represents an information entity, using a sequence of fingerprints for the sequence of blocks, identification results are provided for consecutive fingerprints, wherein an identification result represents an association of a block of information units with a predetermined information entity. Then at least two hypotheses are formed from the identification results for the consecutive fingerprints, wherein a first hypothesis is an assumption for the association of the sequence of blocks with a first information entity, and wherein the second hypothesis is an assumption for the association of the sequence of blocks with the second information entity. Then various hypotheses are examined to obtain an examination result on the basis of which there is then made a statement on the information signal. This achieves a meaningful and reliable time-continuous analysis of an information signal.

Device and method for analyzing an information signal

At an audio encoder, cue codes are generated for one or more audio channels, wherein an envelope cue code is generated by characterizing a temporal envelope in an audio channel. At an audio decoder, E transmitted audio channel(s) are decoded to generate C playback audio channels, where C&#x3e;E&#x2267;1. Received cue codes include an envelope cue code corresponding to a characterized temporal envelope of an audio channel corresponding to the transmitted channel(s). One or more transmitted channel(s) are upmixed to generate one or more upmixed channels. One or more playback channels are synthesized by applying the cue codes to the one or more upmixed channels, wherein the envelope cue code is applied to an upmixed channel or a synthesized signal to adjust a temporal envelope of the synthesized signal based on the characterized temporal envelope such that the adjusted temporal envelope substantially matches the characterized temporal envelope.

Individual channel shaping for BCC schemes and the like

An apparatus for producing a fingerprint signal from an audio signal includes a means for calculating energy values for frequency bands of segments of the audio signal which are successive in time, so as to obtain, from the audio signal, a sequence of vectors of energy values, a means for scaling the energy values to obtain a sequence of scaled vectors, and a means for temporal filtering of the sequence of scaled vectors to obtain a filtered sequence which represents the fingerprint, or from which the fingerprint may be derived. Thus, a fingerprint is produced which is robust against disturbances due to problems associated with coding or with transmission channels, and which is especially suited for mobile radio applications.

Apparatus and method for robust classification of audio signals, and method for establishing and operating an audio-signal database, as well as computer program

In a method for characterizing a signal representing an audio content a measure is determined for a tonality of the signal, whereupon a statement is made about the audio content of the signal on the basis of the measure for the tonality of the signal. The measure for the tonality is derived from a quotient whose numerator is the mean of the summed values of spectral components of the signal exponentiated with a first power and whose denominator is the mean of the summed values of spectral components exponentiated with a second power, the first and second powers differing from each other. The measure for the tonality of the signal for the content analysis is robust in relation to a signal distortion, due e.g. to MP3 coding, and has a high correlation with the content of the analyzed signal.

Method and device for characterizing a signal and method and device for producing an indexed signal

For producing a fingerprint of an audio signal, use is made of information defining a plurality of predetermined fingerprint modi, all of the fingerprint modi relating to the same type of fingerprint, the fingerprint modi, however, providing different fingerprints differing from each other with regard to their data volume, on the one hand, and to their characterizing strength for characterizing the audio signal, on the other hand, the fingerprint modi being pre-determined such that a fingerprint in accordance with a fingerprint modus having a first characterizing strength is convertible to a fingerprint in accordance with a fingerprint modus having a second characterizing strength, without using the audio signal. A predetermined fingerprint modus of the plurality of predetermined fingerprint modi is set and subsequently used for computing a fingerprint using the audio signal. The convertibility feature of the fingerprints having been produced by the different fingerprint modi enables setting a flexible compromise between the data volume and the characterizing strength for certain applications without having to re-generate a fingerprint database with each change of the fingerprint modus. Fingerprint representations scaled with regard to time or frequency may readily be converted to a different fingerprint modus.

Method and apparatus for producing a fingerprint, and method and apparatus for identifying an audio signal

An inventive method for introducing information into a data stream including data about spectral values representing a short-term spectrum of an audio signal first performs a processing of the data stream to obtain the spectral values of the short-term spectrum of the audio signal. Apart from that, the information to be introduced are combined with a spread sequence to obtain a spread information signal, whereupon a spectral representation of the spread information is generated which will then be weighted with an established psychoacoustic maskable noise energy to generate a weighted information signal, wherein the energy of the introduced information is substantially equal to or below the psychoacoustic masking threshold. The weighted information signal and the spectral values of the short-term spectrum of the audio signal will then be summed and afterwards processed again to obtain a processed data stream including both audio information and information to be introduced. By the fact that the information to be introduced are introduced into the data stream without changing to the time domain, the block rastering underlying the short-term spectrum will not be touched, so that introducing a watermark will not lead to tandem encoding effects.

An apparatus for generating an encrypted data stream representing an audio and/or video signal comprises an encoder for encoding an input signal to generate a data stream with a predefined data stream syntax as output signal. The apparatus further comprises an encryption means coupled with the decoder in order to influence encoder internal data and/or the output signal of the encoder in a uniquely reversible manner based on a key such that the generated encrypted data stream comprises payload information differing from payload information of a data stream that would be generated by the apparatus without the presence of an encryption means and that the generated encrypted data stream comprises the predefined data stream syntax. Thereby, a flexible data stream encryption is achieved, wherein the degree of encryption can be freely selected such that the owner of a decoder who does not possess the key, still obtains a rough idea of the audio and/or video signal which might cause him to buy the key in order to hear or view the audio and/or video signal in its full quality. The encoder-specific encryption and decryption concept can be implemented into already existing encoders/decoders with little effort.

Device and method for producing an encoded audio and/or video data stream

In a method for characterizing a signal, which represents an audio content, a measure for a tonality of the signal is determined, whereupon a statement is made about the audio content of the signal based on the measure for the tonality of the signal. The measure for the tonality of the signal for the content analysis is robust against a signal distortion, such as by MP3 encoding, and has a high correlation to the content of the examined signal.

A scalable encoder having a first encoder, a decoder and a second encoder includes, above that, a phase distorter to reduce a non-linear frequency-dependent phase distortion introduced by the first encoder or by the decoder, which results in an increased difference signal of a comparator. Thus, a difference signal with less energy is obtained that the second encoder can encode with less bits, that is with a higher bit efficiency.

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Nuremberg, Germany

Eric Allamanche