US 5,673,363 A · Error concealment method and apparatus of audio signals

Abstract

An apparatus for concealing a frame or multiple of frames where errors have occurred in a digital audio signal which is subband coded and transform coded in units of an error-correctable frame is described. The error concealment apparatus includes an error detector for receiving frequency coefficients representing the encoded digital audio signal and detecting whether an error has occurred for each frame, and a decoder for decoding the frequency coefficients by respective subbands to form a frequency domain of the whole audio signal with respect to the input frequency coefficients. A buffer stores the frequency coefficients decoded by said decoder. Frequency coefficients of a frame or multiple of frames where errors have occurred are reconstructed using predetermined weight values and frequency coefficients of adjacent frames which do not have errors. Once reconstructed, the newly constructed frequency coefficients of the error frames are stored in the buffer also as to update the decoded coefficients stored therein corresponding to the error frames. The contents of the buffer are sent to a synthesis filter bank for converting the frequency coefficients into an audio signal of a time domain, in the same sequence as a decoding sequence.

Claims19

Dependent claims

A method for concealing one or more error frames where errors have occurred in a digital audio signal, wherein the digital audio signal is subband coded and transform coded in units of error-correctable frames, said method comprising the steps of:

(a) receiving input frequency coefficients representing the encoded digital audio signal;
(b) detecting whether an error has occurred for each frame with respect to the input frequency coefficients, to produce an error detection result with respect to each frame;
(c) decoding the frequency coefficients by respective subbands forming a frequency domain of the whole audio signal within each frame with respect to the input frequency coefficients;
(d) storing the frequency coefficients decoded in step (c);
(e) reconstructing the frequency coefficients of one or more error frames where errors have occurred using predetermined weight values and frequency coefficients of subbands adjacent to the error frame(s) among the frequency coefficients belonging to a frame adjacent to the error frame(s), in response to the error detection result in (b);
(f) updating the frequency coefficients of the error frame(s) stored in the step (d) with the reconstructed frequency coefficients reconstructed in step (e);
and
(g) converting the frequency coefficients resulting from step (f) into an audio signal of a time domain, in a same sequence as that of the decoding in step (c).

5 more elements

An apparatus for concealing one or more error frames where errors have occurred in a digital audio signal, wherein the digital audio signal is subband coded and transform coded in units of error-correctable frames, said apparatus comprising:

error detection means for receiving input frequency coefficients representing the encoded digital audio signal, detecting whether an error has occurred for each frame and producing an error detection result;
decoding means for decoding the input frequency coefficients by respective subbands forming a frequency domain of the whole audio signal to provide decoded frequency coefficients;
buffer means for storing the decoded frequency coefficients decoded by said decoding means;
frequency coefficient reconstruction means for reconstructing frequency coefficients of the error frame(s) among frequency coefficients belonging to frames which are stored in said buffer means and are adjacent to the error frame(s) and storing the reconstructed frequency coefficients in said buffer means so as to update the decoded frequency coefficients corresponding to the error frame(s), in response to the error detection result produced by the error detection means;
and
a synthesis filter bank for receiving frequency coefficients stored in said buffer means and converting the frequency coefficients into an audio signal of a time domain, in the same sequence as a decoding sequence.

3 more elements

Dependencies are inferred from the claim text.

Error concealment method and apparatus of audio signals

Life of this patent

Error concealment method and apparatus of audio signals

Life of this patent

Abstract

Claims19