Audio packet loss concealment by transform interpolation
First Claim
1. An audio processing method, comprising:
- receiving sets of packets at an audio processing device via a network, each set having one or more of the packets, each packet having transform coefficients in a frequency domain for reconstructing an audio signal in a time domain that has undergone transform coding;
Determining one or more missing packets in a given one of the sets received, the one or more missing packets sequenced in the given set with a given sequence;
applying a first weight to first transform coefficients of one or more first packets in a first set sequenced before the given set, the one or more first packets having a first sequence in the first set corresponding to the given sequence of the one or more missing packets in the given set;
applying a second weight to second transform coefficients of one or more second packets in a second set sequenced after the given set, the one or more second packets having a second sequence in the second set corresponding to the given sequence of the one or more missing packets in the given set;
interpolating transform coefficients by summing the corresponding first and second weighted transform coefficients;
inserting the interpolated transform coefficients into the given set in place of the one or more corresponding missing packets; and
producing an output audio signal for the audio processing device by performing an inverse transform on the transform coefficients.
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Abstract
In audio processing for an audio or video conference, a terminal receives audio packets having transform coefficients for reconstructing an audio signal that has undergone transform coding. When receiving the packets, the terminal determines whether there are any missing packets and interpolates transform coefficients from the preceding and following good frames. To interpolate the missing coefficients, the terminal weights first coefficients from the preceding good frame with a first weighting, weights second coefficients from the following good frame with a second weighting, and sums these weighted coefficients together for insertion into the missing packets. The weightings can be based on the audio frequency and/or the number of missing packets involved. From this interpolation, the terminal produces an output audio signal by inverse transforming the coefficients.
56 Citations
51 Claims
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1. An audio processing method, comprising:
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receiving sets of packets at an audio processing device via a network, each set having one or more of the packets, each packet having transform coefficients in a frequency domain for reconstructing an audio signal in a time domain that has undergone transform coding; Determining one or more missing packets in a given one of the sets received, the one or more missing packets sequenced in the given set with a given sequence; applying a first weight to first transform coefficients of one or more first packets in a first set sequenced before the given set, the one or more first packets having a first sequence in the first set corresponding to the given sequence of the one or more missing packets in the given set; applying a second weight to second transform coefficients of one or more second packets in a second set sequenced after the given set, the one or more second packets having a second sequence in the second set corresponding to the given sequence of the one or more missing packets in the given set; interpolating transform coefficients by summing the corresponding first and second weighted transform coefficients; inserting the interpolated transform coefficients into the given set in place of the one or more corresponding missing packets; and producing an output audio signal for the audio processing device by performing an inverse transform on the transform coefficients. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. An audio processing device, comprising:
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an audio output interface; a network interface in communication with at least one network and receiving sets of packets of audio, each set having one or more of the packets, each packet having transform coefficients in a frequency domain; memory in communication with the network interface and storing the received packets; a processing unit in communication with the memory and the audio output interface, the processing unit programmed with an audio decoder configured to; determine one or more missing packets in a given one of the sets received, the one or more missing packets sequenced in the given set with a given sequence; apply a first weighting to first transform coefficients of one or more first packets from a first set sequenced before the given set, the one or more first packets having a first sequence in the first set corresponding to the given sequence of the one or more missing packets in the given set; apply a second weighting to second transform coefficients of one or more second packets from a second set sequenced after the given set, the one or more second packets having a second sequence in the second set corresponding to the given sequence of the one or more missing packets in the given set; interpolate transform coefficients by summing the corresponding first and second weighted transform coefficients; insert the interpolated transform coefficients into the given set in place of the corresponding one or more missing packets; and perform an inverse transform on the transform coefficients to produce an output audio signal in a time domain for the audio output interface. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34)
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35. A program storage device having instructions stored thereon for causing a programmable control device to perform an audio processing method, the method comprising:
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receiving sets of packets at an audio processing device via a network, each set having one or more of the packets, each packet having transform coefficients in a frequency domain for reconstructing an audio signal in a time domain that has undergone transform coding; determining one or more missing packets in a given one of the sets received, the one or more missing packets sequenced in the given set with a given sequence; applying a first weight to first transform coefficients of one or more first packets in a first set sequenced before the given set, the one or more first packets having a first sequence in the first set corresponding to the given sequence of the one or more missing packets in the given set; applying a second weight to second transform coefficients of one or more second packets in a second set sequenced after the given set, the one or more second packets having a second sequence in the second set corresponding to the given sequence of the one or more missing packets in the given set; interpolating transform coefficients by summing the corresponding first and second weighted transform coefficients; inserting the interpolated transform coefficients into the given et in place of the corresponding one or more missing packets; and producing an output audio signal for the audio processing device by performing an inverse transform on the transform coefficients. - View Dependent Claims (36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51)
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Specification