Method and apparatus for performing packet loss or frame erasure concealment
First Claim
1. A method for creating an output signal in response to receiving one or more unexpected packets, where an unexpected packet includes a packet that is lost, corrupted, erased or delayed, and where an expected packet includes a packet that is not lost, corrupted, erased or delayed, the method comprising:
- generating one or more synthesized audio signal segments, Rj-1, Rj-2, . . . Rj-k, when a corresponding one or more packets are unexpected;
decoding an expected packet to form an audio signal segment, Rj;
performing an overlap-add operation on the audio signal segment, Rj, to modify a portion of said the audio signal segment Rj-1 with a portion of the audio signal segment Rj, to form a modified audio signal segment, R′
j, where a duration of the portions of both the audio signal segment Rj-1 and the audio signal segment Rj is a function of k; and
outputting the modified audio signal segment R′
j as the output signal.
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Accused Products
Abstract
A method for performing packet loss or Frame Erasure Concealment (FEC) for a speech coder receives encoded frames of compressed speech information transmitted from an encoder. The method determines whether an encoded frame has been lost, corrupted in transmission, or erased, synthesizes properly received frames, and decides on an overlap-add window to use in combining a portion of the synthesized speech signal with a subsequent speech signal resulting from a received and decoded packet, where the size of the overlap-add window is based on the unavailability of packets. If it is determined that an encoded frame has been lost, corrupted in transmission, or erased, the method performed an overlap-add operation on the portion of the synthesized speech signal and the subsequent speech signal, using the decided-on overlap-add window.
19 Citations
3 Claims
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1. A method for creating an output signal in response to receiving one or more unexpected packets, where an unexpected packet includes a packet that is lost, corrupted, erased or delayed, and where an expected packet includes a packet that is not lost, corrupted, erased or delayed, the method comprising:
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generating one or more synthesized audio signal segments, Rj-1, Rj-2, . . . Rj-k, when a corresponding one or more packets are unexpected; decoding an expected packet to form an audio signal segment, Rj; performing an overlap-add operation on the audio signal segment, Rj, to modify a portion of said the audio signal segment Rj-1 with a portion of the audio signal segment Rj, to form a modified audio signal segment, R′
j, where a duration of the portions of both the audio signal segment Rj-1 and the audio signal segment Rj is a function of k; andoutputting the modified audio signal segment R′
j as the output signal. - View Dependent Claims (2, 3)
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Specification