Patent application number | Description | Published |
20090226010 | Mixing of Input Data Streams and Generation of an Output Data Stream Thereform - An apparatus for mixing a plurality of input data streams is described, which has a processing unit adapted to compare the frames of the plurality of input data streams, and determine, based on the comparison, for a spectral component of an output frame of an output data stream, exactly one input data stream of the plurality of input data streams. The output data stream is generated by copying at least a part of an information of a corresponding spectral component of the frame of the determined data stream. Further or alternatively, the control values of the frames of the first and second input data streams are compared, and, if so, the control value is adopted. | 09-10-2009 |
20090319283 | Apparatus and Method for Generating Audio Subband Values and Apparatus and Method for Generating Time-Domain Audio Samples - An embodiment of an apparatus for generating audio subband values in audio subband channels has an analysis windower for windowing a frame of time-domain audio input samples being in a time sequence extending from an early sample to a later sample using an analysis window function having a sequence of window coefficients to obtain windowed samples. The analysis window function has a first group of window coefficients and a second group of window coefficients. The first group of window coefficients is used for windowing later time-domain samples and the second group of window coefficients is used for windowing an earlier time-domain samples. The apparatus further has a calculator for calculating the audio subband values using the windowed samples. | 12-24-2009 |
20100023322 | APPARATUS AND METHOD FOR GENERATING AUDIO SUBBAND VALUES AND APPARATUS AND METHOD FOR GENERATING TIME-DOMAIN AUDIO SAMPLES - An embodiment of an apparatus for generating audio subband values in audio subband channels includes an analysis windower for windowing a frame of time-domain audio input samples being in a time sequence extending from an early sample to a later sample using an analysis window function including a sequence of window coefficients to obtain windowed samples. The analysis window function includes a first number of window coefficients derived from a larger window function including a sequence of a larger second number of window coefficients, wherein the window coefficients of the window function are derived by an interpolation of window coefficients of the larger window function. The apparatus further includes a calculator for calculating the audio subband values using the windowed samples. | 01-28-2010 |
20100198586 | AUDIO TRANSFORM CODING USING PITCH CORRECTION - A processed representation of an audio signal having a sequence of frames is generated by sampling the audio signal within first and second frames of the sequence of frames, the second frame following the first frame, the sampling using information on a pitch contour of the first and second frames to derive a first sampled representation. The audio signal is sampled within the second and third frames, the third frame following the second frame in the sequence of frames. The sampling uses the information on the pitch contour of the second frame and information on a pitch contour of the third frame to derive a second sampled representation. A first scaling window is derived for the first sampled representation, and a second scaling window is derived for the second sampled representation, the scaling windows depending on the samplings applied to derive the first sampled representations or the second sampled representation. | 08-05-2010 |
20100217607 | Audio Decoder, Audio Encoder, Methods for Decoding and Encoding an Audio Signal and Computer Program - An audio decoder for providing a decoded representation of an audio content on the basis of an encoded representation of the audio content comprises a linear-prediction-domain decoder core configured to provide a time-domain representation of an audio frame on the basis of a set of linear-prediction domain parameters associated with the audio frame and a frequency-domain decoder core configured to provide a time-domain representation of an audio frame on the basis of a set of frequency-domain parameters, taking into account a transform window out of a set comprising a plurality of different transform windows. The audio decoder comprises a signal combiner configured to overlap-and-add-time-domain representations of subsequent audio frames encoded in different domains, in order to smoothen a transition between the time-domain representations of the subsequent frames. The set of transform windows comprises one or more windows specifically adapted for a transition between a frequency-domain core mode and a linear-prediction-domain core mode. | 08-26-2010 |
20100241433 | AUDIO ENCODER, AUDIO DECODER AND AUDIO PROCESSOR HAVING A DYNAMICALLY VARIABLE WARPING CHARACTERISTIC - An audio encoder, an audio decoder or an audio processor includes a filter ( | 09-23-2010 |
20110112670 | Device and Method for Manipulating an Audio Signal Having a Transient Event - A signal manipulator for manipulating an audio signal having a transient event may have a transient remover, a signal processor and a signal inserter for inserting a time portion in a processed audio signal at a signal location where the transient event was removed before processing by the transient remover, so that a manipulated audio signal has a transient event not influenced by the processing, whereby the vertical coherence of the transient event is maintained instead of any processing performed in the signal processor, which would destroy the vertical coherence of a transient. | 05-12-2011 |
20110170711 | Audio Encoder, Audio Decoder, Methods for Encoding and Decoding an Audio Signal, and a Computer Program - An encoder for providing an audio stream on the basis of a transform-domain representation of an input audio signal includes a quantization error calculator configured to determine a multi-band quantization error over a plurality of frequency bands of the input audio signal for which separate band gain information is available. The encoder also includes an audio stream provider for providing the audio stream such that the audio stream includes information describing an audio content of the frequency bands and information describing the multi-band quantization error. | 07-14-2011 |
20110173007 | Audio Encoder and Audio Decoder - An audio encoder for encoding segments of coefficients, the segments of coefficients representing different time or frequency resolutions of a sampled audio signal, the audio encoder including a processor for deriving a coding context for a currently encoded coefficient of a current segment based on a previously encoded coefficient of a previous segment, the previously encoded coefficient representing a different time or frequency resolution than the currently encoded coefficient. The audio encoder further includes an entropy encoder for entropy encoding the current coefficient based on the coding context to obtain an encoded audio stream. | 07-14-2011 |
20110173008 | Audio Encoder and Decoder for Encoding Frames of Sampled Audio Signals - An audio encoder adapted for encoding frames of a sampled audio signal to obtain encoded frames, wherein a frame has a number of time domain audio samples, having a predictive coding analysis stage for determining information on coefficients of a synthesis filter and information on a prediction domain frame based on a frame of audio samples. The audio encoder further has a frequency domain transformer for transforming a frame of audio samples to the frequency domain to obtain a frame spectrum and an encoding domain decider for deciding whether encoded data for a frame is based on the information on the coefficients and on the information on the prediction domain frame, or based on the frame spectrum. Moreover, the audio encoder has a controller for determining an information on a switching coefficient when the encoding domain decider decides that encoded data of a current frame is based on the information on the coefficients and the information on the prediction domain frame when encoded data of a previous frame was encoded based on a previous frame spectrum and a redundancy reducing encoder for encoding the information on the prediction domain frame, the information on the coefficients, the information on the switching coefficient and/or the frame spectrum. | 07-14-2011 |
20110173009 | Apparatus and Method for Encoding/Decoding an Audio Signal Using an Aliasing Switch Scheme - An apparatus for encoding an audio signal includes the windower for windowing a first block of the audio signal using an analysis window having an aliasing portion and a further portion. The apparatus furthermore includes a processor for processing the first sub-block of the audio signal associated with the aliasing portion by transforming the sub-block from a domain into a different domain subsequent to windowing the first sub-block to obtain the processed first sub-block, and for processing a second sub-block of the audio signal associated with the further portion by transforming the second sub-block from the domain into the different domain before windowing the second sub-block to obtain a processed second sub-block. The apparatus furthermore includes a transformer for converting the processed first sub-block and the processed second sub-block from the different domain into a further different domain using the same block transform rule to obtain a converted first block which may then be compressed using any of the well-known data compression algorithms. Thus, a critically sampled switch between two coding modes can be obtained, since aliasing portions occurring in two different domains are matched to each other. | 07-14-2011 |
20110173010 | Audio Encoder and Decoder for Encoding and Decoding Audio Samples - An audio encoder for encoding audio samples has a first time domain aliasing introducing encoder configured to decode audio samples in a first encoding domain and having a first framing rule, a start window and a stop window. The audio encoder further has a second encoder configured to encode samples in a second encoding domain and having a predetermined frame size number of audio samples, and a coding warm-up period number of audio samples, the second encoder having a different second framing rule, a frame of the second encoder being an encoded representation of a number of successive audio samples that is equal to the predetermined frame size number of audio samples. The audio encoder further has a controller switching from the first to the second encoder and for modifying the second framing rule or for modifying the start or the stop window of the first encoder. | 07-14-2011 |
20110173011 | Audio Encoder and Decoder for Encoding and Decoding Frames of a Sampled Audio Signal - An audio encoder adapted for encoding frames of a sampled audio signal to obtain encoded frames, wherein a frame includes a number of time domain audio samples. The audio encoder includes a predictive coding analysis stage for determining information on coefficients of a synthesis filter and a prediction domain frame based on a frame of audio samples. The audio encoder further includes a time-aliasing introducing transformer for transforming overlapping prediction domain frames to the frequency domain to obtain prediction domain frame spectra, wherein the time-aliasing introducing transformer is adapted for transforming the overlapping prediction domain frames in a critically-sampled way. Moreover, the audio encoder includes a redundancy reducing encoder for encoding the prediction domain frame spectra to obtain the encoded frames based on the coefficients and the encoded prediction domain frame spectra. | 07-14-2011 |
20110173012 | Noise Filler, Noise Filling Parameter Calculator Encoded Audio Signal Representation, Methods and Computer Program - A noise filler for providing a noise-filled spectral representation of an audio signal on the basis of an input spectral representation of the audio signal has a spectral region identifier configured to identify spectral regions of the input spectral representation spaced from non-zero spectral regions of the input spectral representation by at least one intermediate spectral region, to obtain identified spectral regions, and a noise inserter configured to selectively introduce noise into the identified spectral regions to obtain the noise-filled spectral representation of the audio signal. A noise filling parameter calculator for providing a noise filling parameter on the basis of a quantized spectral representation of an audio signal has a spectral region identifier, as mentioned above, and a noise value calculator configured to selectively consider quantization errors of the identified spectral regions for a calculation of the noise filling parameter. Accordingly, an encoded audio signal representation representing the audio signal can be obtained. | 07-14-2011 |
20110200125 | Method for Encoding a Symbol, Method for Decoding a Symbol, Method for Transmitting a Symbol from a Transmitter to a Receiver, Encoder, Decoder and System for Transmitting a Symbol from a Transmitter to a Receiver - In a method for encoding a symbol it is determined whether the symbol can be encoded by a codeword of a first codebook. In case this is true, the appropriate codeword for the symbol is selected from the first codebook. Otherwise, a codeword is selected from the first codebook indicating that the symbol cannot be encoded by a codeword of the first codebook and the symbol is split into a plurality of first sub-symbols and for at least one of the first sub-symbols a codeword is selected from a second codebook. Also a corresponding method for decoding is described. | 08-18-2011 |
20110200198 | Low Bitrate Audio Encoding/Decoding Scheme with Common Preprocessing - An audio encoder has a common preprocessing stage, an information sink based encoding branch such as spectral domain encoding branch, a information source based encoding branch such as an LPC-domain encoding branch and a switch for switching between these branches at inputs into these branches or outputs of these branches controlled by a decision stage. An audio decoder has a spectral domain decoding branch, an LPC-domain decoding branch, one or more switches for switching between the branches and a common post-processing stage for post-processing a time-domain audio signal for obtaining a post-processed audio signal. | 08-18-2011 |
20110202352 | Apparatus and a Method for Generating Bandwidth Extension Output Data - An apparatus for generating bandwidth extension output data for an audio signal has a noise floor measurer, a signal energy characterizer and a processor. The audio signal has components in a first frequency band and components in a second frequency band, the bandwidth extension output data are adapted to control a synthesis of the components in the second frequency band. The noise floor measurer measures noise floor data of the second frequency band for a time portion of the audio signal. The signal energy characterizer derives energy distribution data, the energy distribution data characterizing an energy distribution in a spectrum of the time portion of the audio signal. The processor combines the noise floor data and the energy distribution data to obtain the bandwidth extension output data. | 08-18-2011 |
20110202353 | Apparatus and a Method for Decoding an Encoded Audio Signal - An apparatus for decoding an encoded audio signal having first and second portions encoded in accordance with first and second encoding algorithms, respectively, BWE parameters for the first and second portions and a coding mode information indicating a first or a second decoding algorithm, includes first and second decoders, a BWE module and a controller. The decoders decode portions in accordance with decoding algorithms for time portions of the encoded signal to obtain decoded signals. The BWE module has a controllable crossover frequency and is configured for performing a bandwidth extension algorithm using the first decoded signal and the BWE parameters for the first portion, and for performing a bandwidth extension algorithm using the second decoded signal and the bandwidth extension parameter for the second portion. The controller controls the crossover frequency for the BWE module in accordance with the coding mode information. | 08-18-2011 |
20110202354 | Low Bitrate Audio Encoding/Decoding Scheme Having Cascaded Switches - An audio encoder has a first information sink oriented encoding branch such as a spectral domain encoding branch, a second information source or SNR oriented encoding branch such as an LPC-domain encoding branch, and a switch for switching between the first encoding branch and the second encoding branch, wherein the second encoding branch has a converter into a specific domain different from the spectral domain such as an LPC analysis stage generating an excitation signal, and wherein the second encoding branch furthermore has a specific domain coding branch such as LPC domain processing branch, and a specific spectral domain coding branch such as LPC spectral domain processing branch, and an additional switch for switching between the specific domain coding branch and the specific spectral domain coding branch. An audio decoder has a first domain decoder such as a spectral domain decoding branch, a second domain decoder such as an LPC domain decoding branch for decoding a signal such as an excitation signal in the second domain, and a third domain decoder such as an LPC-spectral decoder branch and two cascaded switches for switching between the decoders. | 08-18-2011 |
20110202355 | Audio Encoding/Decoding Scheme Having a Switchable Bypass - An apparatus for encoding includes a first domain converter, a switchable bypass, a second domain converter, a first processor and a second processor to obtain an encoded audio signal having different signal portions represented by coded data in different domains, which have been coded by different coding algorithms. Corresponding decoding stages in the decoder together with a bypass for bypassing a domain converter allow the generation of a decoded audio signal with high quality and low bit rate. | 08-18-2011 |
20110202358 | Apparatus and a Method for Calculating a Number of Spectral Envelopes - An apparatus calculates a number of spectral envelopes to be derived by a spectral band replication (SBR) encoder, wherein the SBR encoder is adapted to encode an audio signal using a plurality of sample values within a predetermined number of subsequent time portions in an SBR frame extending from an initial time to a final time, the predetermined number of subsequent time portions being arranged in a time sequence given by the audio signal. The apparatus has a decision value calculator for determining a decision value, the decision value measuring a deviation in spectral energy distributions of a pair of neighboring time portions. The apparatus further has a detector for detecting a violation of a threshold by the decision value and a processor for determining a first envelope border between the pair of neighboring time portions when the violation of the threshold is detected. | 08-18-2011 |
20110238425 | Multi-Resolution Switched Audio Encoding/Decoding Scheme - An audio encoder for encoding an audio signal has a first coding branch, the first coding branch comprising a first converter for converting a signal from a time domain into a frequency domain. Furthermore, the audio encoder has a second coding branch comprising a second time/frequency converter. Additionally, a signal analyzer for analyzing the audio signal is provided. The signal analyzer, on the hand, determines whether an audio portion is effective in the encoder output signal as a first encoded signal from the first encoding branch or as a second encoded signal from a second encoding branch. On the other hand, the signal analyzer determines a time/frequency resolution to be applied by the converters when generating the encoded signals. An output interface includes, in addition to the first encoded signal and the second encoded signal, a resolution information identifying the resolution used by the first time/frequency converter and used by the second time/frequency converter. | 09-29-2011 |
20110238426 | Audio Decoder, Audio Encoder, Method for Decoding an Audio Signal, Method for Encoding an Audio Signal, Computer Program and Audio Signal - An audio decoder for providing a decoded audio information on the basis of an entropy encoded audio information includes a context-based entropy decoder configured to decode the entropy-encoded audio information in dependence on a context, which context is based on a previously-decoded audio information in a non-reset state-of-operation. The context-based entropy decoder is configured to select a mapping information, for deriving the decoded audio information from the encoded audio information, in dependence on the context. The context-based entropy decoder includes a context resetter configured to reset the context for selecting the mapping information to a default context, which default context is independent from the previously-decoded audio information, in response to a side information of the encoded audio information. | 09-29-2011 |
20110282675 | Apparatus and Method for Generating a Synthesis Audio Signal and for Encoding an Audio Signal - An apparatus for generating a synthesis audio signal using a patching control signal has a first converter, a spectral domain patch generator, a high frequency reconstruction manipulator and a combiner. The first converter is configured for converting a time portion of an audio signal into a spectral representation. The spectral domain patch generator is configured for performing a plurality of different spectral domain patching algorithms, wherein each patching algorithm generates a modified spectral representation having spectral components in an upper frequency band derived from corresponding spectral components in a core frequency band of the audio signal. The spectral domain patch generator is furthermore configured to select a first spectral domain patching algorithm from the plurality of patching algorithms for a first time portion and a second spectral domain patching algorithm from the plurality of patching algorithm for a second different time portion in accordance with the patching control signal to obtain the modified spectral representation. | 11-17-2011 |
20120010880 | APPARATUS, METHOD AND COMPUTER PROGRAM FOR GENERATING A REPRESENTATION OF A BANDWIDTH-EXTENDED SIGNAL ON THE BASIS OF AN INPUT SIGNAL REPRESENTATION USING A COMBINATION OF A HARMONIC BANDWIDTH-EXTENSION AND A NON-HARMONIC BANDWIDTH-EXTENSION - An apparatus for generating a representation of a bandwidth-extended signal on the basis of an input signal representation includes a phase vocoder configured to obtain values of a spectral domain representation of a first patch of the bandwidth-extended signal on the basis of the input signal representation. The apparatus also includes a value copier configured to copy a set of values of the spectral domain representation of the first patch, which values are provided by the phase vocoder, to obtain a set of values of a spectral domain representation of a second patch, wherein the second patch is associated with higher frequencies than the first patch. The apparatus is configured to obtain the representation of the bandwidth-extended signal using the values of the spectral domain representation of the first patch and the values of the spectral domain representation of the second patch. | 01-12-2012 |
20120022881 | AUDIO ENCODER, AUDIO DECODER, ENCODED AUDIO INFORMATION, METHODS FOR ENCODING AND DECODING AN AUDIO SIGNAL AND COMPUTER PROGRAM - An audio decoder for providing a decoded audio information on the basis of an encoded audio information includes a window-based signal transformer configured to map a time-frequency representation, which is described by the encoded audio information, to a time-domain representation. The window-based signal transformer is configured to select a window, out of a plurality of windows including windows of different transition slopes and windows of different transform length, on the basis of a window information. The audio decoder includes a window selector configured to evaluate a variable-codeword-length window information in order to select a window for a processing of a given portion of the time-frequency representation associated with a given frame of the audio information. | 01-26-2012 |
20120158409 | Bandwidth Extension Encoder, Bandwidth Extension Decoder and Phase Vocoder - A bandwidth extension encoder for encoding an audio signal has a signal analyzer, a core encoder and a parameter calculator. The audio signal has a low frequency signal having a core frequency band and a high frequency signal having an upper frequency band. The signal analyzer is configured for analyzing the audio signal, the audio signal having a block of audio samples, the block having a specified length in time. The signal analyzer is furthermore configured for determining from a plurality of analysis windows an analysis window to be used for performing a bandwidth extension in a bandwidth extension decoder. The core encoder is configured for encoding the low frequency signal to acquire an encoded or frequency signal. The parameter calculator is configured for calculating bandwidth extension parameters from the high frequency signal. | 06-21-2012 |
20120253797 | MULTI-MODE AUDIO CODEC AND CELP CODING ADAPTED THEREFORE - In an embodiment, bitstream elements of sub-frames are encoded differentially to a global gain value so that a change of the global gain value results in an adjustment of an output level of the decoded representation of the audio content. Concurrently, the differential coding saves bits. Even further, the differential coding enables the lowering of the burden of globally adjusting the gain of an encoded bitstream. In another embodiment, a global gain control across CELP coded frames and transform coded frames is achieved by co-controlling the gain of the codebook excitation of the CELP codec, along with a level of the transform or inverse transform of the transform coded frames. In another embodiment, the gain value determination in CELP coding is performed in the weighted domain of the excitation signal. | 10-04-2012 |
20120265540 | AUDIO ENCODER, AUDIO DECODER, METHOD FOR ENCODING AN AUDIO INFORMATION, METHOD FOR DECODING AN AUDIO INFORMATION AND COMPUTER PROGRAM USING A DETECTION OF A GROUP OF PREVIOUSLY-DECODED SPECTRAL VALUES - An audio decoder for providing a decoded audio information includes a arithmetic decoder for providing a plurality of decoded spectral values on the basis of an arithmetically-encoded representation of the spectral values and a frequency-domain-to-time-domain converter for providing a time-domain audio representation using the decoded spectral values. The arithmetic decoder is configured to select a mapping rule describing a mapping of a code value onto a symbol code in dependence on a context state. The arithmetic decoder is configured to determine or modify the current context state in dependence on a plurality of previously-decoded spectral values. The arithmetic decoder is configured to detect a group of a plurality of previously-decoded spectral values, which fulfill, individually or taken together, a predetermined condition regarding their magnitudes, and to determine the current context state in dependence on a result of the detection. | 10-18-2012 |
20120278086 | AUDIO ENCODER, AUDIO DECODER, METHOD FOR ENCODING AN AUDIO INFORMATION, METHOD FOR DECODING AN AUDIO INFORMATION AND COMPUTER PROGRAM USING A REGION-DEPENDENT ARITHMETIC CODING MAPPING RULE - An audio decoder for providing a decoded audio information includes an arithmetic decoder for providing a plurality of decoded spectral values on the basis of an arithmetically-encoded representation of the spectral values and a frequency-domain-to-time-domain converter for providing a time-domain audio representation using decoded spectral values. The arithmetic decoder is configured to select a mapping rule describing a mapping of a code value onto a symbol code in dependence on a context state. The arithmetic decoder is configured to determine a numeric current context value describing the current context state in dependence on a plurality of previously decoded spectral values and also in dependence on whether a spectral value to be decoded is in a first predetermined frequency region or in a second predetermined frequency region. | 11-01-2012 |
20120330670 | AUDIO ENCODER, AUDIO DECODER, METHOD FOR ENCODING AN AUDIO INFORMATION, METHOD FOR DECODING AN AUDIO INFORMATION AND COMPUTER PROGRAM USING AN ITERATIVE INTERVAL SIZE REDUCTION - An audio decoder has an arithmetic decoder for providing decoded spectral values on the basis of an arithmetically-encoded representation and a frequency-domain-to-time-domain converter for providing a time-domain audio representation. The arithmetic decoder selects a mapping rule describing a mapping of a code value onto a symbol code in dependence on a numeric current context value describing a current context state. The arithmetic decoder determines the numeric current context value in dependence on a plurality of previously decoded spectral values. The arithmetic decoder evaluates at least one table using an iterative interval size reduction to determine whether the numeric current context value is identical to a table context value described by an entry of the table or lies within an interval described by entries of the table, and derives a mapping rule index value describing a selected mapping table. | 12-27-2012 |
20130003992 | DEVICE AND METHOD FOR MANIPULATING AN AUDIO SIGNAL HAVING A TRANSIENT EVENT - A signal manipulator for manipulating an audio signal having a transient event may have a transient remover, a signal processor and a signal inserter for inserting a time portion in a processed audio signal at a signal location where the transient event was removed before processing by the transient remover, so that a manipulated audio signal has a transient event not influenced by the processing, whereby the vertical coherence of the transient event is maintained instead of any processing performed in the signal processor, which would destroy the vertical coherence of a transient. | 01-03-2013 |
20130010983 | DEVICE AND METHOD FOR MANIPULATING AN AUDIO SIGNAL HAVING A TRANSIENT EVENT - A signal manipulator for manipulating an audio signal having a transient event may have a transient remover, a signal processor and a signal inserter for inserting a time portion in a processed audio signal at a signal location where the transient event was removed before processing by the transient remover, so that a manipulated audio signal has a transient event not influenced by the processing, whereby the vertical coherence of the transient event is maintained instead of any processing performed in the signal processor, which would destroy the vertical coherence of a transient. | 01-10-2013 |
20130010985 | DEVICE AND METHOD FOR MANIPULATING AN AUDIO SIGNAL HAVING A TRANSIENT EVENT - A signal manipulator for manipulating an audio signal having a transient event may have a transient remover, a signal processor and a signal inserter for inserting a time portion in a processed audio signal at a signal location where the transient event was removed before processing by the transient remover, so that a manipulated audio signal has a transient event not influenced by the processing, whereby the vertical coherence of the transient event is maintained instead of any processing performed in the signal processor, which would destroy the vertical coherence of a transient. | 01-10-2013 |
20130013301 | AUDIO ENCODER, AUDIO DECODER, METHOD FOR ENCODING AND AUDIO INFORMATION, METHOD FOR DECODING AN AUDIO INFORMATION AND COMPUTER PROGRAM USING A HASH TABLE DESCRIBING BOTH SIGNIFICANT STATE VALUES AND INTERVAL BOUNDARIES - An audio decoder includes an arithmetic decoder for providing a plurality of decoded spectral values on the basis of an arithmetically encoded representation of the spectral values, and a frequency-domain-to-time-domain converter for providing a time-domain audio representation using the decoded spectral values. The arithmetic decoder selects a mapping rule describing a mapping of a code value onto a symbol code in dependence on a context state described by a numeric current context value. The arithmetic decoder determines the numeric current context value in dependence on a plurality of previously decoded spectral values. The arithmetic decoder evaluates a hash table, entries of which define both significant state values and boundaries of intervals of numeric context values, in order to select the mapping rule. A mapping rule index value is individually associated to a numeric context value being a significant state value. | 01-10-2013 |
20130013322 | AUDIO ENCODER, AUDIO DECODER, METHOD FOR ENCODING AND DECODING AN AUDIO INFORMATION, AND COMPUTER PROGRAM OBTAINING A CONTEXT SUB-REGION VALUE ON THE BASIS OF A NORM OF PREVIOUSLY DECODED SPECTRAL VALUES - An audio decoder has an arithmetic decoder for providing decoded spectral values on the basis of an arithmetically-encoded representation and a frequency-domain-to-time-domain converter for providing a time-domain audio representation. The arithmetic decoder selects a mapping rule describing a mapping of a code value onto a symbol code in dependence on a context state described by a numeric current context value which is determined in dependence on previously decoded spectral values. The arithmetic decoder obtains a plurality of context subregion values on the basis of previously decoded spectral values and derives a numeric current context value associated with one or more spectral values to be decoded in dependence on stored context subregion values. The arithmetic decoder computes the norm of a vector formed by a plurality of previously decoded spectral values in order to obtain a common context subregion value. An audio encoder uses a similar concept. | 01-10-2013 |
20130013323 | AUDIO ENCODER, AUDIO DECODER, METHOD FOR ENCODING AND AUDIO INFORMATION, METHOD FOR DECODING AN AUDIO INFORMATION AND COMPUTER PROGRAM USING A MODIFICATION OF A NUMBER REPRESENTATION OF A NUMERIC PREVIOUS CONTEXT VALUE - An audio decoder includes an arithmetic decoder for providing decoded spectral values on the basis of an arithmetically-encoded representation of the spectral values and a frequency-domain-to-time-domain converter for providing a time-domain audio representation using the decoded spectral values. The arithmetic decoder selects a mapping rule describing a mapping of a code value onto a symbol code in dependence on a context state described by a numeric current context value, and determines the numeric current context value in dependence on a plurality of previously-decoded spectral values. The arithmetic decoder modifies a number representation of a numeric previous context value, describing a context state associated with one or more previously decoded spectral values, in dependence on a context subregion value, to acquire a number representation of a numeric current context value describing a context state associated with one or more spectral values to be decoded. An audio encoder uses a similar concept. | 01-10-2013 |
20130041673 | APPARATUS, METHOD AND COMPUTER PROGRAM FOR GENERATING A WIDEBAND SIGNAL USING GUIDED BANDWIDTH EXTENSION AND BLIND BANDWIDTH EXTENSION - An apparatus, method and computer program for generating a wideband signal using a lowband input signal includes a processor for performing a guided bandwidth extension operation using transmitted parameters and a blind bandwidth extension operation only using derived parameters rather than transmitted parameters. To this end, the processor includes a parameter generator for generating the parameters for the blind bandwidth extension operation. | 02-14-2013 |
20130066640 | AUDIO ENCODING/DECODING SCHEME HAVING A SWITCHABLE BYPASS - An apparatus for encoding includes a first domain converter, a switchable bypass, a second domain converter, a first processor and a second processor to obtain an encoded audio signal having different signal portions represented by coded data in different domains, which have been coded by different coding algorithms. Corresponding decoding stages in the decoder together with a bypass for bypassing a domain converter allow the generation of a decoded audio signal with high quality and low bit rate. | 03-14-2013 |
20130090934 | APPARATUS AND METHOD FOR GENERATING A SYNTHESIS AUDIO SIGNAL AND FOR ENCODING AN AUDIO SIGNAL - An apparatus for generating a synthesis audio signal using a patching control signal has a first converter, a spectral domain patch generator, a high frequency reconstruction manipulator and a combiner. The first converter is configured for converting a time portion of an audio signal into a spectral representation. The spectral domain patch generator is configured for performing a plurality of different spectral domain patching algorithms, wherein each patching algorithm generates a modified spectral representation having spectral components in an upper frequency band derived from corresponding spectral components in a core frequency band of the audio signal. The spectral domain patch generator is furthermore configured to select a first spectral domain patching algorithm from the plurality of patching algorithms for a first time portion and a second spectral domain patching algorithm from the plurality of patching algorithm for a second different time portion in accordance with the patching control signal to obtain the modified spectral representation. | 04-11-2013 |
20130096930 | Multi-Resolution Switched Audio Encoding/Decoding Scheme - An audio encoder for encoding an audio signal has a first coding branch, the first coding branch comprising a first converter for converting a signal from a time domain into a frequency domain. Furthermore, the audio encoder has a second coding branch comprising a second time/frequency converter. Additionally, a signal analyzer for analyzing the audio signal is provided. The signal analyzer, on the hand, determines whether an audio portion is effective in the encoder output signal as a first encoded signal from the first encoding branch or as a second encoded signal from a second encoding branch. On the other hand, the signal analyzer determines a time/frequency resolution to be applied by the converters when generating the encoded signals. An output interface includes, in addition to the first encoded signal and the second encoded signal, a resolution information identifying the resolution used by the first time/frequency converter and used by the second time/frequency converter. | 04-18-2013 |
20130226570 | APPARATUS AND METHOD FOR PROCESSING AN AUDIO SIGNAL AND FOR PROVIDING A HIGHER TEMPORAL GRANULARITY FOR A COMBINED UNIFIED SPEECH AND AUDIO CODEC (USAC) - An apparatus for processing an audio signal is provided. The apparatus has a signal processor and a configurator. The configurator is adapted to configure the signal processor based on configuration information such that a configurable upsampling factor is equal to a first upsampling value when a first ratio of the second configurable number of samples to a first configurable number of samples has a first ratio value. Moreover, the configurator is adapted to configure the signal processor such that the configurable upsampling factor is equal to a different second upsampling value, when a different second ratio of the second configurable number of samples to the first configurable number of samples has a different second ratio value. The first or the second ratio value is not an integer value. | 08-29-2013 |
20130226594 | AUDIO ENCODER, AUDIO DECODER, METHOD FOR ENCODING AND AUDIO INFORMATION, METHOD FOR DECODING AN AUDIO INFORMATION AND COMPUTER PROGRAM USING AN OPTIMIZED HASH TABLE - An audio decoder includes an arithmetic decoder for providing decoded spectral values on the basis of an arithmetically encoded representation thereof, and a frequency-domain-to-time-domain converter for providing a time-domain audio representation. The arithmetic decoder selects a mapping rule describing a mapping of a code value onto a symbol code representing a spectral value, or a most significant bit-plane thereof, in a decoded form, in dependence on a context state described by a numeric current context value. The arithmetic decoder determines the numeric current context value in dependence on a plurality of previously decoded spectral values. It evaluates a hash table, entries of which define both significant state values amongst the numeric context values and boundaries of intervals of numeric context values, in order to select the mapping rule, wherein the hash table ari_hash_m is defined as given in FIGS. | 08-29-2013 |
20130238343 | APPARATUS AND METHOD FOR GENERATING AUDIO SUBBAND VALUES AND APPARATUS AND METHOD FOR GENERATING TIME-DOMAIN AUDIO SAMPLES - An embodiment of an apparatus for generating audio subband values in audio subband channels has an analysis windower for windowing a frame of time-domain audio input samples being in a time sequence extending from an early sample to a later sample using an analysis window function having a sequence of window coefficients to obtain windowed samples. The analysis window function has a first group of window coefficients and a second group of window coefficients. The first group of window coefficients is used for windowing later time-domain samples and the second group of window coefficients is used for windowing an earlier time-domain samples. The apparatus further has a calculator for calculating the audio subband values using the windowed samples. | 09-12-2013 |
20140016785 | AUDIO ENCODER AND DECODER HAVING A FLEXIBLE CONFIGURATION FUNCTIONALITY - An audio decoder for decoding an encoded audio signal, the encoded audio signal including a first channel element and a second channel element in a payload section of a data stream and first decoder configuration data for the first channel element and second decoder configuration data for the second channel element in a configuration section of the data stream, includes: a data stream reader for reading the configuration data for each channel element in the configuration section and for reading the payload data for each channel element in the payload section; a configurable decoder for decoding the plurality of channel elements; and a configuration controller for configuring the configurable decoder so that the configurable decoder is configured in accordance with the first decoder configuration data when decoding the first channel element and in accordance with the second decoder configuration data when decoding the second channel element. | 01-16-2014 |
20140016787 | FRAME ELEMENT LENGTH TRANSMISSION IN AUDIO CODING - Frame elements which shall be made available for skipping may are transmitted more efficiently by arranging that a default payload length information is transmitted separately within a configuration block, with the length information within the frame elements, in turn, being subdivided into a default payload length flag followed, if the default payload length flag is not set, by a payload length value explicitly coding the payload length of the respective frame element. However, if the default payload length flag is set, an explicit transmission of the payload length may be avoided. Rather, any frame element, the default extension payload length flag of which is set, has the default payload length and any frame element, the default extension payload length flag of which is not set, has a payload length corresponding to the payload length value. By this measure, transmission effectiveness is increased. | 01-16-2014 |
20140019146 | FRAME ELEMENT POSITIONING IN FRAMES OF A BITSTREAM REPRESENTING AUDIO CONTENT - A better compromise between a too high bitstream and decoding overhead on the one hand and flexibility of frame element positioning on the other hand is achieved by arranging that each of the sequence of frames of the bitstream has a sequence of N frame elements and, on the other hand, the bitstream has a configuration block having a field indicating the number of elements N and a type indication syntax portion indicating, for each element position of the sequence of N element positions, an element type out of a plurality of element types with, in the sequences of N frame elements of the frames, each frame element being of the element type indicated, by the type indication portion, for the respective element position at which the respective frame element is positioned within the sequence of N frame elements of the respective frame in the bitstream. | 01-16-2014 |
20140081645 | AUDIO ENCODER, AUDIO DECODER, METHOD FOR ENCODING AN AUDIO INFORMATION, METHOD FOR DECODING AN AUDIO INFORMATION AND COMPUTER PROGRAM USING A DETECTION OF A GROUP OF PREVIOUSLY-DECODED SPECTRAL VALUES - An audio decoder for providing a decoded audio information includes a arithmetic decoder for providing a plurality of decoded spectral values on the basis of an arithmetically-encoded representation of the spectral values and a frequency-domain-to-time-domain converter for providing a time-domain audio representation using the decoded spectral values. The arithmetic decoder is configured to select a mapping rule describing a mapping of a code value onto a symbol code in dependence on a context state. The arithmetic decoder is configured to determine or modify the current context state in dependence on a plurality of previously-decoded spectral values. The arithmetic decoder is configured to detect a group of a plurality of previously-decoded spectral values, which fulfill, individually or taken together, a predetermined condition regarding their magnitudes, and to determine the current context state in dependence on a result of the detection. | 03-20-2014 |
20140236605 | AUDIO ENCODER, AUDIO DECODER, METHODS FOR ENCODING AND DECODING AN AUDIO SIGNAL, AND A COMPUTER PROGRAM - An encoder for providing an audio stream on the basis of a transform-domain representation of an input audio signal includes a quantization error calculator configured to determine a multi-band quantization error over a plurality of frequency bands of the input audio signal for which separate band gain information is available. The encoder also includes an audio stream provider for providing the audio stream such that the audio stream includes information describing an audio content of the frequency bands and information describing the multi-band quantization error. | 08-21-2014 |
20140343953 | MULTI-MODE AUDIO CODEC AND CELP CODING ADAPTED THEREFORE - In an embodiment, bitstream elements of sub-frames are encoded differentially to a global gain value so that a change of the global gain value results in an adjustment of an output level of the decoded representation of the audio content. Concurrently, the differential coding saves bits. Even further, the differential coding enables the lowering of the burden of globally adjusting the gain of an encoded bitstream. In another embodiment, a global gain control across CELP coded frames and transform coded frames is achieved by co-controlling the gain of the codebook excitation of the CELP codec, along with a level of the transform or inverse transform of the transform coded frames. In another embodiment, the gain value determination in CELP coding is performed in the weighted domain of the excitation signal. | 11-20-2014 |
20150081312 | AUDIO ENCODER, AUDIO DECODER, METHOD FOR ENCODING AND AUDIO INFORMATION, METHOD FOR DECODING AN AUDIO INFORMATION AND COMPUTER PROGRAM USING A MODIFICATION OF A NUMBER REPRESENTATION OF A NUMERIC PREVIOUS CONTEXT VALUE - An audio decoder includes an arithmetic decoder for providing decoded spectral values on the basis of an arithmetically-encoded representation of the spectral values and a frequency-domain-to-time-domain converter for providing a time-domain audio representation using the decoded spectral values. The arithmetic decoder selects a mapping rule describing a mapping of a code value onto a symbol code in dependence on a context state described by a numeric current context value, and determines the numeric current context value in dependence on a plurality of previously-decoded spectral values. The arithmetic decoder modifies a number representation of a numeric previous context value, describing a context state associated with one or more previously decoded spectral values, in dependence on a context subregion value, to acquire a number representation of a numeric current context value describing a context state associated with one or more spectral values to be decoded. An audio encoder uses a similar concept. | 03-19-2015 |