Method and arrangement in a communication system
First Claim
1. A method for manipulating a received sound signal to produce a sound signal, wherein the received sound signal is received from a packet-switched network that loses some packets, the method comprising steps of:
- receiving a first received frame from the packet-switched network, wherein;
the first received frame is part of the received sound signal, andthe packet-switched network has packet loss;
producing a first signal frame corresponding to the first received frame, wherein;
the first signal frame is part of the sound signal, anda second received frame is normally produced contiguously with the first received frame;
determining after beginning the first-listed producing step that the second received frame is currently unavailable for production; and
producing an expanded portion after the determining step, wherein;
the first signal frame and the expanded portion are contiguous parts of the sound signal,the expanded portion corresponds to a different amount of the received sound signal than either the first or second received frames, andthe first signal frame and the expanded portion have different time lengths in the sound signal.
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Accused Products
Abstract
The present invention relates to the decoding-/playback part of received sound data packets in systems for transmission of sound over packet switched networks. According to the invention, the lengths of received signal frames are manipulated by performing time expansion or time compression of one or more signal frames at time varying intervals and with time varying lengths of the expansion or the compression, said intervals and said lengths being determined so as to maintain a continuous flow of signal samples to be played back.
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Citations
49 Claims
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1. A method for manipulating a received sound signal to produce a sound signal, wherein the received sound signal is received from a packet-switched network that loses some packets, the method comprising steps of:
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receiving a first received frame from the packet-switched network, wherein; the first received frame is part of the received sound signal, and the packet-switched network has packet loss; producing a first signal frame corresponding to the first received frame, wherein; the first signal frame is part of the sound signal, and a second received frame is normally produced contiguously with the first received frame; determining after beginning the first-listed producing step that the second received frame is currently unavailable for production; and producing an expanded portion after the determining step, wherein; the first signal frame and the expanded portion are contiguous parts of the sound signal, the expanded portion corresponds to a different amount of the received sound signal than either the first or second received frames, and the first signal frame and the expanded portion have different time lengths in the sound signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27)
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28. A method for manipulating a received sound signal to product;
a sound signal, wherein the received sound signal is received from a packet-switched network that loses some packets, the method comprising steps of; receiving a first received frame that is part of the received sound signal; producing a first signal frame corresponding to the first received frame, wherein the first signal frame is part of the sound signal; determining after beginning the first-listed producing step that a second received frame currently unavailable for production due to latency; producing a first expanded portion after the first-listed determining step, wherein; the first expanded portion and the first signal frame are contiguous parts of the sound signal, the first signal frame and the second signal frame would be contiguous parts of the sound signal in situations where the second received frame is available for production, and the first expanded portion has a different size than either the first or second received frames; receiving a third received frame that is part of the received sound signal; producing a third signal frame corresponding to the third received frame, wherein the third signal frame is part of the sound signal; determining after beginning the second-listed producing step that a fourth received frame currently unavailable for production due to packet loss; and producing a second expanded portion after the second-listed determining step, wherein; the second expanded portion and the third signal frame are contiguous parts of the sound signal, the third signal frame and the fourth signal frame would be contiguous parts of the sound signal in situations where the fourth received frame is available for production, the second expanded portion has a different size than either the third or fourth received frames, and the first and third signal frames have a frame size that is different from a size of the first expanded portion. - View Dependent Claims (29)
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30. A method for manipulating a received sound signal to produce a sound signal, wherein the received sound signal is received from a packet-switched network that loses some packets, the method comprising steps of:
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receiving a first received frame that is part of the received sound signal; producing a first signal frame corresponding to the first received frame, wherein; the first signal frame is part of the sound signal, and a second received frame is produced contiguously with the first received frame when the second received frame is available; determining after beginning the first-listed producing step that the second received frame is currently unavailable for production due to packet loss; and producing an expanded portion after the determining step, wherein; the first signal frame and the expanded portion are contiguous parts of the sound signal, and the expanded portion has a size that is different than a frame size of the first signal frame.
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31. A method for manipulating a sequence of digitized sound signal frames of a sound signal, the sound signal frames being decoded from packet data received from a packet switched network, the method including:
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decoding a first sound signal frame from the packet data received from the packet switched network; determining that, due to the occurrence of packet loss, the packet data is not available for decoding a second sound signal frame which should be contiguous with the first sound signal frame; and producing an expanded frame portion to be contiguous with the first sound signal frame, wherein the expanded frame portion represents a part of the sound signal that is different from the part represented by the first signal frame, and wherein the time length of the expanded frame portion in the sound signal is different from the time length of first sound signal frame, and wherein a following frame decoded from the packet data received from the packet switched network is provided to be contiguous with the expanded frame portion. - View Dependent Claims (32, 33, 34, 35, 36, 37, 38, 39)
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40. A system for manipulating a sequence of digitized sound signal frames of a sound signal, the sound signal frames being decoded from packet data received from a packet switched network, the system including:
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a memory element for storing a computer program and vectors of samples of the received sound signal together with corresponding signal segments; and a processor unit for executing a computer program causing the system to; decode a first sound signal frame from the packet data received from the packet switched network; determine that, due to the occurrence of packet loss, the packet data is not available for decoding a second sound signal frame which should be contiguous with the first sound signal frame; and produce an expanded frame portion to be contiguous with the first sound signal frame, wherein the expanded frame portion represents a part of the sound signal that is different from the part represented by the first signal frame, and wherein the time length of the expanded frame portion in the sound signal is different from the time length of first sound signal frame, and wherein a following frame decoded from the packet data received from the packet switched network is provided to be contiguous with the expanded frame portion.
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41. A system for manipulating a received sound signal to produce a sound signal, wherein the received sound signal is received from a packet-switched network that loses some packets, the system comprising:
a timing recovery and lost frame substitution for producing a first signal frame corresponding to a first received frame from the packet-switched network, wherein the first received frame is part of the received sound signal, the packet-switched network has packet loss, the first signal frame is part of the sound signal, and a second received frame is normally produced contiguously with the first received frame; determining after beginning producing the first signal frame that the second received frame is currently unavailable for production, and producing an expanded portion after determining that the second received frame is currently unavailable for production, wherein the first signal frame and the expanded portion are contiguous parts of the sound signal, the expanded portion corresponds to a different amount of the received sound signal than either the first or second received frames, and the first signal frame and the expanded portion have different time lengths in the sound signal. - View Dependent Claims (42, 43, 44, 45, 46, 47, 48, 49)
Specification