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The method of adpcm codec and adpcm decoder packet loss concealment

A packet loss concealment, codec technology, applied in instruments, speech analysis, etc., to achieve the effects of good sound quality, good coding performance, and strong adaptability

Active Publication Date: 2020-11-03
AKG ACOUSTICS
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the latter two techniques require a significant amount of delay to account for "skew", which is basically unacceptable for a professional wireless microphone with a total delay (audio analog input to audio analog output) of ~3 ms

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  • The method of adpcm codec and adpcm decoder packet loss concealment
  • The method of adpcm codec and adpcm decoder packet loss concealment
  • The method of adpcm codec and adpcm decoder packet loss concealment

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Embodiment Construction

[0026] In ADPCM coded audio transmission, the prediction error e={e for all M subbands 1 ,e 2 ,...,e m ,...,e M-1 ,e M} are sent to the receiver and used to decode the original audio signal and adjust the ADPCM decoder parameters, which include such as figure 1 Prediction coefficients, predictor filter registers and (inverse) quantization function shown. If e is received incorrectly, i.e. loss is detected by a suitable checksum, the audio output of the ADPCM decoder x out Extrapolated surrogate signal x usually provided by packet loss concealment (PLC) PLC replace.

[0027] From figure 2 The timeline shows that the transition between the correct and alternate signal (and vice versa) is cross-faded in the uncompressed audio domain to reduce its audibility. However, even this method cannot avoid correctly signaling x dec and the alternative signal x PLC More or less audible transients from time to time. Additionally, signal artifacts can be produced due to ADPCM mist...

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Abstract

The invention relates to a method for concealing packet loss in an ADPCM codec, and relates to an ADPCM decoder with a PLC circuit. The method is characterized in that, in the correct signal (x dec ) and the alternative signal provided by the PLC circuit (x PLC During the predetermined transition period between ), the substitute signal (x PLC,m ) and calculate the predicted signal (x pred,m ) difference between (d PLC,m ) and dequantization prediction error (d dec,m ) combined to receive the dequantized combined prediction error (d comb,m ), which is added to the prediction signal (x pred,m ) to get the combined transition signal (x comb,m ), as the output signal during the transition period (x out＝ x comb ) and the basis for tuning all decoder parameters. The method may be implemented in an error combiner circuit having two inputs, one of which is connected to the output of the PLC circuit and the other is connected to the input of the ADPCM decoder, and two output, one of which is used for its output signal (x comb ), while the other is used to tune the ADPCM decoder.

Description

technical field [0001] The present invention relates to a method for packet loss concealment in an ADPCM codec, by this method, in the decoder, when each sub-band code quantization prediction error (e m ) when a packet is lost, an alternative signal (x PLC ), and replace it with the otherwise decoded correct signal (x dec ) is used to get the output signal (x out ). Background technique [0002] Such an approach is described, for example, in [0003] M. Serizawa and Y. Nozawa, "A Packet Loss Concealment Method Using Pitch Waveform Repetition and Inner State Updates for a Subband ADPCM Wideband Speech Codec," IEEE Symposium on Speech Coding, pp. 68–70, 2002 (“A PacketLoss Concealment Method using Pitch Waveform Repetition and Internal Stateupdate on the Decoded speech for the Sub-band ADPCM Wideband Speech Codec,” IEEE Speech Coding Workshop, pp.68–70, 2002.) [0004] J Thyssen, RW Zopf, JH Chen "ITU-T G.722 Packet Loss Concealment Standard Candidate" ("ACandidate for th...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G10L19/005
CPCG10L19/005G10L19/0017G10L19/032
Inventor Z.马库斯C.保罗
Owner AKG ACOUSTICS