Error concealment for sub-band coded audio signals

An audio signal, encoded technology, applied in the direction of forward error control, speech analysis, code conversion, etc., to achieve the effect of reducing unnecessary waste

Active Publication Date: 2012-05-30
NXP BV
View PDF4 Cites 13 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] Known repetition and replacement techniques have the disadvantage that the receiver requires

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Error concealment for sub-band coded audio signals
  • Error concealment for sub-band coded audio signals
  • Error concealment for sub-band coded audio signals

Examples

Experimental program
Comparison scheme
Effect test

Example Embodiment

[0049] The MPEG Audio Layer II audio codec used in DAB is a subband encoder. Compression is performed in the time domain using a filter bank that generates 32 subbands equally spaced in frequency with a bandwidth of 750 Hz at a sampling rate of 48 kHz. All these subbands are not equally perceptually related. The first subband covers a bandwidth from 0 Hz (DC) to 750 Hz, which corresponds to the 8 critical bands of the human auditory system, while the second subband covers only 4 critical bands.

[0050] Isolated bit errors in subbands create time-domain discontinuities that can typically be heard as band-limited "click" noise. Bit error bursts tend to randomize the time domain signal of corrupted subbands, which can be heard as band-limited white noise.

[0051] The inventors have noticed that these artifacts in the first subband in the range from 0 to 750 Hz are the most annoying. This is not only due to the relatively low frequency resolution of the MPEG Audio Layer II fi...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

PUM

No PUM Login to view more

Abstract

A decoder and method of decoding a sub-band coded digital audio signal are disclosed. The decoder comprises: an input, for receiving sub-band coefficients for a plurality of sub-bands of the audio signal; an error detection unit (20), adapted to analyze the content of a sequence of coefficients in one of the sub-bands, to derive for each coefficient an indication of whether the coefficient has been corrupted by an error of a predefined type; an error masking unit (30), adapted to generate from the sequence a modified sequence of coefficients for the sub-band, wherein errors of the predefined type are attenuated; a coefficient combination unit (40), adapted to combine the received coefficients and the modified coefficients, in dependence upon the indication of error; and a signal reconstruction unit (50), adapted to reconstruct the audio signal using the combined coefficients.

Description

technical field [0001] The present invention relates to a method and apparatus for concealing errors in a received digital audio signal that has been coded using a subband coding (SBC) scheme. In particular, it relates to a DAB receiver implementing a source decoder according to the MPEG-1 Audio Layer II (MP2) standard defined in ISO / IEC 11172-3. Background technique [0002] Digital Audio Broadcasting (DAB) receivers are subject to harsh transmission conditions especially in mobile and automotive environments. Although the channel decoder includes several error correction schemes, residual bit errors cannot be completely avoided. [0003] Frame-level concealment techniques that mask the effects of such bit errors are well known in the art. A simple example is to mute the output for the duration of an audio frame in which an error is detected. Another possibility is repetition, where adjacent frames are used instead of frames containing bit errors. If the stream includes...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

Application Information

Patent Timeline
no application Login to view more
IPC IPC(8): G10L19/00G10L19/005G10L19/02
CPCG10L19/005H04L1/0072G10L19/0204H03M7/3046
Inventor 克里斯托弗・马克・马库斯
Owner NXP BV
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Try Eureka
PatSnap group products

Browse by: Latest US Patents, China's latest patents, Technical Efficacy Thesaurus, Application Domain, Technology Topic.

© 2024 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap