摘要:
The invention makes it possible to combine a scaleable audio coder with TNS technology. According to the inventive method for encoding time signals (x1) sampled in a first sampling rate, second time signals (x2) with a sampling rate smaller than the first sampling rate are generated (12). The second time signals (x2) are then encoded (14) according to a first coding algorithm, and written into a bit stream (xAUS) (16). The encoded second time signals (x2c) are then decoded (14) again and are transformed (23, 24) into the frequency range, as are the first time signals. TNS prediction coefficients are then calculated (25) from a spectral representation of the first time signals (X1). The transformed output signal (X2cd) of the coder/decoder (14) with the first coding algorithm and the spectral representation (X1) of the first time signal are subjected to a prediction of the frequency (27) in order to obtain spectral residual values for both signals using the prediction coefficients calculated on the basis of the first time signals alone. These two signals are evaluated against each other (26, 28). The evaluated spectral residual values (Xb) are then encoded by means of a second coding algorithm in order to obtain coded evaluated spectral residual values (Xcb). These evaluated spectral residual values are written into the bit stream (xAUS) in addition to side information with the prediction coefficients.
摘要:
The invention relates to devices and methods for producing coded data, for reproducing coded data and for re-signing originally signed data based on the fact that the coded data in addition to the coded media information, comprises the necessary information for decoding the data in addition to a signature thereof which produces the coded data. The source of the coded data is thus traceable. Reproduction of coded data is allowed within defined limits by the producer of the coded data for friends or relatives for example, yet large-scale duplication of the coded data is seen as an act of piracy. The data pirate can be traced back by means of the signature, since the signature is optionally secured by means of an embedded water-mark signature. Since the issue at stake is a concept wherein only legal use should occur for coded data, unauthorised removal of the coding is a criminal act. The inventive concept enables the wrong doer to be determined and takes into account both the ownership status of the provider with regard to a defined reproduction of media information and also has the potentiality of being acceptable to the market.
摘要:
The invention relates to a method for extracting a signal identifier from a time signal, according to which the temporal occurrence of signal edges is detected in the time signal (12), whereby a signal edge has a specified temporal length. In addition, the temporal interval between two selected detected signal edges is determined (14). A frequency value is calculated (16) from said determined interval and is assigned to a time of occurrence of the frequency value in the time signal in order to obtain a co-ordinate tuple from the frequency value and the time of occurrence for said frequency value. A signal identifier is created from a plurality of co-ordinate tuples (18), each co-ordinate tuple containing a frequency value and a time of occurrence, in such a way that the signal identifier comprises a sequence of signal identifier values, which reproduce the temporal course of the time signal. The extracted signal identifier is based on signal edges of the time signal and reproduces the temporal course of the time signal. The signal identifier thus characterises the time signal and is stable in relation to changes to said time signal.
摘要:
The invention relates to a method for masking defects in a stream of audio data. Defects in a stream of audio data which was previously intact are detected and a spectral energy of a sub-group of the intact audio data is then calculated. After a model has been created for replacement data, based on the spectral energy calculated for the sub-group of intact audio data, replacement data is generated for defective or absent audio data, said replacement data corresponding to the sub-group, based on the model.
摘要:
According to the invention, in order to characterise an information signal having an amplitude-time course with local extreme values, the local extreme values of the information signal are determined (10), a local extreme value being defined by a moment and an amplitude. Surface information of highs or lows of the information signal is then determined (11) in the event of a unidimensional amplitude of the information signal, or volume information of lows or highs is determined (11) in the event of a two-dimensional amplitude of the information signal. A low or a high is defined by a temporal section of the information signal, said section extending from the moment of a local extreme value to a temporally adjacent value of the information signal, which has the same amplitude as the local extreme value. Surface or volume information of a plurality of highs and lows is characteristic of the information signal and enables a broader characterisation of the information signal, the construction of an information signal database or the identification of an information signal by means of an existing information signal database. Surface or volume information is both characteristic of the information signal and is resistant, due to its integral nature, to information signal variations in the form of overlays or distortion.
摘要:
The invention relates to a method for generating an identifier for an audio signal (12) that contains a tone produced by the instrument, according to which a discrete amplitude-time representation of the audio signal is firstly produced (14), whereby the amplitude-time representation has a number of successive amplitude values for a number of successive points in time, and one point in time is assigned to each amplitude value. An identifier (18) for the audio signal is extracted (16) from the amplitude-time representation. An instrument database is created from a number of identifiers for a number of audio signals that contain tones of a number of instruments. The instrument database is utilized to determined the type of test instrument while using a test identifier for an audio signal that had been produced by an unknown instrument. As for identifying musical instruments, an instrument can be precisely identified by using the amplitude-time representation of a tone that is produced by an instrument.
摘要:
According to the inventive method for determining a coding block raster on which a decoded signal is based, a segment of the decoded signal is picked out first (1), this section beginning at a certain output sampling value of the decoded signal. Said segment is then converted into a spectral representation (12), whereupon said spectral representation is evaluated in relation to a predetermined criterion (13) in order to obtain an evaluation result for the segment. This procedure is repeated for a plurality of different segments beginning at different output scanning values, in order to obtain a plurality of evaluation results. Finally, said plurality of evaluation results is searched (14) in order to establish the evaluation result that has an extreme value compared to the other evaluation results, in such a way that it can be assumed that the segment to which this evaluation result is allocated matches the coding block raster on which the decoded signal is based. According to the invention, this method can be used to determine the coding block raster for any decoded signal that has no explicit information about its coding block raster.
摘要:
A process for coding a time-discrete stereo signal having a first and a second channel (R, L) makes it possible to scale stereo coding. A monosignal (M) is first formed from the stereo signal, then coded, and the coded monosignal is transmitted in a bit stream. Finally, the coded monosignal is decoded again and stereo information is formed on the basis of the coded/decoded monosignal (M') and of the first and second channels (R, L). This stereo information is coded and also written in the bit stream to yield a bit stream with a completely coded monolayer and a layer with coded stereo information.
摘要:
The invention relates to a method for detecting a transient in a discrete-time audiosignal (x(k)) which is carried out entirely in the time domain. Said method comprises a step in which the discrete-time audiosignal is segmented so as generate consecutive segments of identical length with unfiltered discrete-time audiosignals (xs(T), xs(T-1), xs(T-2), ...), after which the discrete-time audiosignal (xs(T)) in a current segment is filtered. Thereafter there are two options: either the energy (Ef(T)) of the filtered discrete-time audiosignal (Ys(T)) in the current segment can be compared with the energy (Ef(T-1)) of the filtered discrete-time audiosignal (Ys(T-1)) in a preceding segment, or a current relationship can be generated between the energy (Ef(T)) of the filtered discrete-time audiosignal (Ys(T)) in the current segment and the energy (Eu(T)) of the unfiltered discrete-time audiosignal (Xs(T)) in the current segment and said current relationship compared with a corresponding preceding relationship. On the basis of the one comparison and/or the other comparison it is determined whether a transient is present in the discrete-time audiosignal.
摘要:
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.