摘要:
An efficient encoded representation of a first and a second input audio signal can be derived using correlation information indicating a correlation between the first and the second input audio signals, when a signal characterization information, indicating at least a first or a second, different characteristic of the input audio signal is additionally considered. Phase information indicating a phase relation between the first and the second input audio signals is derived, when the input audio signals have the first characteristic. The phase information and a correlation measure are included into the encoded representation when the input audio signals have the first characteristic, and only the correlation information is included into the encoded representation when the input audio signals have the second characteristic.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
An audio encoder, an audio decoder or an audio processor includes a filter for generating a filtered audio signal, the filter having a variable warping characteristic, the characteristic being controllable in response to a time-varying control signal, the control signal indicating a small or no warping characteristic or a comparatively high warping characteristic. Furthermore, a controller is connected for providing the time-varying control signal, which depends on the audio signal. The filtered audio signal can be introduced to an encoding processor having different encoding algorithms, one of which is a coding algorithm adapted to a specific signal pattern. Alternatively, the filter is a post-filter receiving a decoded audio signal.
摘要:
In coding of an audio signal, coded signals with low quality and bit rate on the one hand and coded signals with high quality and bit rate on the other hand are transmitted to a decoder. At first, the audio signal is coded with low bit rate and is transmitted to the decoder before an additional coded signal is transmitted to the decoder, which either alone or together with the first coded signal upon decoding thereof provides a decoded signal with high quality within the decoder. In this manner, a low-quality decoded signal is generated first in the decoder before decoding of the high-quality signal is possible.
摘要:
A process for transmitting and/or storing digital signals of multiple chals. This process is suited, in particular, for transmitting the five channels of 3/2 stereophony as well as for transmitting two stereo channels and three additional commentary channels. In this manner, by way of illustration, television programs with multi-language audio signals can be transmitted. This process is distinguished in that by reduction of the to-be-transmitted data, only a bit rate of 384 kbit/s is required for transmission. The reduction of the data is achieved by the K input channels being imaged in segments onto the N.ltoreq.K virtual spectral data channels, by the spectral data channels being quantized, coded, and transmitted taking into consideration the principles of psychoacoustics, and by K output channels being reproduced from the transmitted bit stream with the aid of a transmitted list from the N.ltoreq.K spectral data channels.
摘要:
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.
摘要:
A watermark signal provider comprises a time-frequency-domain waveform provider to provide time-domain waveforms for a plurality of frequency subbands. The time-frequency-domain waveform provider is configured to map a given value of a time-frequency-domain representation onto a bit shaping function, a temporal extension of which is longer than a bit interval, such that there is a temporal overlap between bit shaped functions provided for temporally subsequent values of the time-frequency-domain representation of the same frequency subband. A time-domain waveform of a given frequency subband contains a plurality of bit shaped functions provided for temporally subsequent values of the time-frequency-domain representation. The water mark signal provider further has a time-domain waveform combiner.
摘要:
An embedder for embedding a watermark to be embedded into an input information representation comprises an embedding parameter determiner that is implemented to apply a derivation function once or several times to an initial value to obtain an embedding parameter for embedding the watermark into the input information representation. Further, the embedder comprises a watermark adder that is implemented to provide the input information representation with the watermark using the embedding parameter. The embedder is implemented to select how many times the derivation function is to be applied to the initial value.