Abstract:
The invention provides an efficient technique for encoding a multi-channel audio signal. The invention relies on the principle of encoding (Sl) a signal representation of one or more of the multiple channels in a first encoding process, and encoding another signal representation of one or more channels in a second, filter-based encoding process. A basic idea according to the invention is to select (S2), for the second encoding process, a combination of i) frame division configuration of an overall encoding frame into a set of sub-frames, and ii) filter length for each sub-frame, according to a predetermined criterion. The second signal representation is then encoded (S3) in each sub-frame of the overall encoding frame according to the selected combination. The possibility to select frame division configuration and at the same time adjust the filter length for each sub-frame provides added degrees of freedom, and generally results in improved performance.
Abstract:
A vector quantizer includes a lattice quantizer (10) approximating a vector x by a lattice vector belonging to a lattice ? 0 . A lattice vector decomposer (14) connected to the lattice quantizer successively decomposes the lattice vector into a sequence of quotient vectors y, and a sequence of remainder vectors r i on successive lattices ? I-1 by lattice division with a corresponding predetermined sequence of integers p
Abstract:
The signal processing is based on the c oncept of using a time-domain aliased (12, TDA) frame as a basis for time segmen tation (14) and spectral analysis (16), performing segmentation in time based on the time-domain aliased frame and performing spectral analysis based on the resulting time segments. The time resolution of the overall "segmented" time-to-frequenc y transform can thus be changed by simply adapting the time segmentation to ob tain a suitable number of time segments based on which spectral analysis is applied. The overall set of spectral coefficients, obtained for all the segments, provides a selectable time-frequency tiling of the original signal frame.
Abstract:
The basic concept of the present invention is to extrapolate a partially known spatial covariance matrix of a multi-channel signal in the parameter domain. The extrapolated covariance matrix is used with the downcoded downmix signal in order to efficiently generate an estimate of a linear combination of the multi-channel signals.
Abstract:
A network processing node (e.g., MGW, MRFP) and method are described herein that can: (1) receive packets on a first heterogeneous link (e.g., wireless link); (2) manipulate the received packets based on known characteristics about a second heterogeneous link (e.g., "Internet" link); and (3) send the manipulated packets on the second heterogeneous link (e.g., "Internet" link). For example, the network processing node can manipulate the received packets by adding redundancy, removing redundancy, frame aggregating (re-packetizing), recovering lost packets and/or re-transmitting packets.
Abstract:
A first signal representation of one or more of the multiple channels is encoded (Sl) in a first encoding process, and a second signal representation of one or more of the multiple channels is encoded (S2) in a second, filter-based encoding process. Filter smoothing can be used to reduce the effects of coding artifacts. However, conventional filter smoothing generally leads to a rather large performance reduction and is therefore not widely used. It has been recognized that coding artifacts are perceived as more annoying than temporary reduction in stereo width, and that they are especially annoying when the coding filter provides a poor estimate of the target signal; the poorer the estimate, the more disturbing artifacts. Therefore, signal-adaptive filter smoothing (S3) is introduced in the second encoding process or a corresponding decoding process as a new general concept for solving the problems of the prior art.
Abstract:
In signal processing using digital filtering the representation of a filter is adapted depending on the filter characteristics. If e.g. a digital filter is represented by filter coefficients for transform bands Nos. 0, 1,..., K in the frequency domain, a reduced digital filter having coefficients for combined transform bands, i.e. subsets of the transformed bands, Nos. 0, 1,..., L, is formed and only these coefficients are stored. When the actual filtering in the digital filter is to be performed, an actual digital filter is obtained by expanding the coefficients of the reduced digital filter according to a mapping table and then used instead of the original digital filter.
Abstract:
A method for audio coding and decoding comprises primary encoding (12) of a present audio signal sample into an encoded representation (T(n)), and non-causal encoding (13) of a first previous audio signal sample into an encoded enhancement representation (ET(n-N+)). The method further comprises providing of the encoded representations to an end user. At the end user, the method comprises primary decoding (52) of the encoded representation (T*(n)) into a present received audio signal sample, and non- causal decoding (53) of the encoded enhancement representation (ET*(n-N+)) into an enhancement first previous received audio signal sample. The method further comprises improving of a first previous received audio signal sample, corresponding to the first previous audio signal sample, based on the enhancement first previous received audio signal sample. Devices and systems for audio coding and decoding are also presented.
Abstract:
A parametric multi-channel surround audio bitstream is received in a multi-channel decoder (13). The received spatial parameters are in combining unit (37) transformed into a new set of spatial parameters that are used in order to obtain a decoding of the multi-channel surround sound that is not a simple equivalent of the original input multi-channel surround signal but e.g. may be personalized by making the transformation based on a representation of user head related filters obtained from a unit (43). Such personalized spatial parameters may also be obtained by combining the received spatial parameters and a representation of the user head related filters with a set of additional rendering parameters that for example are interactively determined by the user and thus are time dependent.
Abstract:
A transient detector (100) analyzes (110) a given frame n of the input audio signal to determine, based on audio signal characteristics of the given frame n, a transient hangover indicator for a following frame n+1, and signals (120) the determined transient hangover indicator to an associated audio encoder (10) to enable proper encoding of the following frame n+1.