摘要:
An apparatus for generating an enhanced signal from an input signal (600), wherein the enhanced signal has spectral values for an enhancement spectral region, the spectral values for the enhancement spectral regions not being contained in the input signal (600), comprises a mapper (602) for mapping a source spectral region of the input signal to a target region in the enhancement spectral region, the source spectral region comprising a noise-filling region (302); and a noise filler (604) configured for generating first noise values for the noise-filling region (302) in the source spectral region of the input signal and for generating second noise values for a noise region in the target region, wherein the second noise values are decorrelated from the first noise values or for generating second noise values for a noise region in the target region, wherein the second noise values are decorrelated from first noise values in the source region.
摘要:
There are provided methods and apparatus for performing modified cosine transformation (MDCT) with an analysis/synthesis windowing function, using an analysis windowing function (40, 50, 60, 70, 90) having a meandering portion (44, 64, 94) which passes a linear function (40', 60') in correspondence of at least four points (#1, #2, #3, #4).
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 apparatus for generating an enhanced signal from an input signal (600), wherein the enhanced signal has spectral values for an enhancement spectral region, the spectral values for the enhancement spectral regions not being contained in the input signal (600), comprises a mapper (602) for mapping a source spectral region of the input signal to a target region in the enhancement spectral region, the source spectral region comprising a noise-filling region (302); and a noise filler (604) configured for generating first noise values for the noise-filling region (302) in the source spectral region of the input signal and for generating second noise values for a noise region in the target region, wherein the second noise values are decorrelated from the first noise values or for generating second noise values for a noise region in the target region, wherein the second noise values are decorrelated from first noise values in the source region.
摘要:
An apparatus for processing an audio signal including a sequence of blocks of spectral values, includes: a processor for calculating an aliasing-affected signal using at least one first modification value for a first block of the sequence of blocks and using at least one different second modification value for a second block of the sequence of blocks and for estimating an aliasing-error signal representing an aliasing-error in the aliasing-affected signal; and a combiner for combining the aliasing-affected signal and the aliasing-error signal such that a processed signal obtained by the combining is an aliasing-reduced or aliasing-free signal.
摘要:
Apparatus for decoding an encoded audio signal comprising an encoded core signal (1), comprising: a core decoder (1400) for decoding the encoded core signal (1401) to obtain a decoded core signal; a tile generator (1404) for generating one or more spectral tiles having frequencies not included in the decoded core signal using a spectral portion of the decoded core signal; and a cross-over filter (1406) for spectrally cross-over filtering the decoded core signal and a first frequency tile having frequencies extending from a gap filling frequency (309) to an upper border frequency or for spectrally cross-over filtering a first frequency tile and a second frequency tile.
摘要:
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.
摘要:
An apparatus for encoding comprises a first domain converter (510), a switchable bypass (50), a second domain converter (410), a first processor (420) and a second processor (520) 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.
摘要:
An audio encoder comprises 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 comprises 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.