摘要:
Representations of spatial audio scenes using higher-order Ambisonics HOA technology typically require a large number of coefficients per time instant. This data rate is too high for most practical applications that require real-time transmission of audio signals. According to the invention, the compression is carried out in spatial domain instead of HOA domain. The (N+1)2 input HOA coefficients are transformed into (N+1)2 equivalent signals in spatial domain, and the resulting (N+1)2 time-domain signals are input to a bank of parallel perceptual codecs. At decoder side, the individual spatial-domain signals are decoded, and the spatial-domain coefficients are transformed back into HOA domain in order to recover the original HOA representation.
摘要:
Higher-order Ambisonics HOA is a representation of spatial sound fields that facilitates capturing, manipulating, recording, transmission and playback of complex audio scenes with superior spatial resolution, both in 2D and 3D. The sound field is approximated at and around a reference point in space by a Fourier-Bessel series. The invention uses space warping for modifying the spatial content and/or the reproduction of sound-field information that has been captured or produced as a higher-order Ambisonics representation. Different warping characteristics are feasible for 2D and 3D sound fields. The warping is performed in space domain without performing scene analysis or decomposition. Input HOA coefficients with a given order are decoded to the weights or input signals of regularly positioned (virtual) loudspeakers.
摘要:
To form an audio signal, frequency components of the audio signal which are allotted to a first subband are formed by means of a subband decoder using supplied fundamental period values which respectively indicate a fundamental period for the audio signal. Frequency components of the audio signal which are allotted to a second subband are formed by exciting an audio synthesis filter using an excitation signal which is specific to the second subband. To produce this excitation signal, an excitation signal generator derives a fundamental period parameter from the fundamental period values. The fundamental period parameter is used by the excitation signal generator to form pulses with a pulse shape which is dependent on the fundamental period parameter at an interval of time which is determined by the fundamental period parameter and to mix them with a noise signal.
摘要:
At the time of encoding audio content, the finally required data rate for delivery to the customer may be unknown. A data format is disclosed that is optimized for serving as Intermediate Format for efficient and fast recoding, to obtain one or more standard complying lossy encoded data streams with flexible data rates. Encoding can be performed in two steps that are inter-coordinated for cooperating, but may be locally and/or temporally separate. Between the partial encoders encoding parameters and/or auxiliary data are transmitted in a separate parameter enhancement layer, which complements a lossy data stream and can be used by the second encoder or transcoder for fast and computationally efficient implementation of the second encoding step. An additional lossless enhancement layer allows lossless reconstruction.
摘要:
According to the invention, an excitation signal is generated as a result of sampled excitation values in order to excite an audio synthesis filter, the generated sampled excitation values being continuously stored in an adaptive codebook. A noise generator is provided which continuously generates random sampled values. A sequence of the stored sampled excitation values is selected from the adaptive codebook based on a fed audio fundamental frequency parameter by means of which a time gap between the sequence that is to be selected and the actual time reference is predefined. The excitation signal is generated by mixing the selected sequence with a random sequence encompassing actual random sampled valued of the noise generator.
摘要:
In a method for detecting a leak in a double pipe, a medium located in an intermediate chamber between the interior and exterior pipe is moved toward a first end of the pipe, whereupon the medium flows in from the second end. On the first end the medium is examined for any leakage of a characteristic material, upon the detection of which a leakage signal is generated and a location of the leakage is calculated based on the transport time of the characteristic material from the leakage to the first end and on the mass flow of the medium. A corresponding device contains a conveyor unit for moving the medium through the intermediate chamber. A material sensor is disposed at the first end for examining the medium for the characteristic material. A control and analysis unit is provided for generating a leakage signal and calculating the location of the leakage.
摘要:
In lossy based lossless coding a PCM audio signal passes through a lossy encoder to a lossy decoder. The lossy encoder provides a lossy bit stream. The difference signal between the PCM signal and the lossy decoder output is lossless encoded, providing an extension bit stream. The invention facilitates enhancing a lossy perceptual audio encoding/decoding by an extension that enables mathematically exact reproduction of the original waveform using enhanced de-correlation, and provides additional data for reconstructing at decoder site an intermediate-quality audio signal. The lossless extension can be used to extend the widely used mp3 encoding/decoding to lossless encoding/decoding and superior quality mp3 encoding/de-coding.
摘要:
A device for sealing off and monitoring a volume includes two seals. Support elements space the seals apart from one another. At least one conduit is disposed between the seals and the support elements. The at least one conduit has an inlet opening and an outlet opening for a medium. At least one sensor is associated with the outlet line. The two seals have edges being tightly joined to one another leaving the inlet and outlet openings of the at least one conduit free. The support elements are formed of a flow-hindering material. At least two devices may be tightly joined together to form a field, with the outlet opening of the at least one conduit of one of the at least two devices being connected to the inlet opening of the at least one conduit of another of the at least two devices.
摘要:
The present invention provides method and device for transcoding between audio coding formats with different time-frequency analysis domains, as used for example by MP EG-AAC and mp3, particularly for facilitated and faster transcoding between such audio signals. A method for transcoding a framed audio signal from a first parameter domain into a second parameter domain comprises linearly transforming two or more parameters of the first parameter domain to at least one parameter of the second parameter domain, wherein the two or more parameters of the first parameter domain come from different frames of the audio signal in the first parameter domain. The linear transformation can be described as a matrix and implemented as a look-up table, wherein the matrix transformation coefficients below -60 Decibels are neglected.
摘要:
An integer-reversible MDCT transformation is split into consecutive lifting steps, each introducing considerable rounding errors to the signal. Without noise shaping the rounding error noise will impact all frequency bins of the transformed signal equally. This is a particular problem for low signal level frequency bins. The invention limits the impact of rounding error noise coming with each lifting step in the integer-reversible transformation on the data rate of a lossless audio codec. The filter coefficients of an adaptive noise shaping filter for transform coefficients are adapted in individual lifting steps according to the current time domain signal characteristics. As an alternative, an auto-regressive pre-filter can be added in front of the lossless transformation, for raising the level of frequency regions with low power to decrease the dominance of rounding errors in these areas. Both processes can be combined to further improve lossless codec compression ratio.