Voice transcoder
First Claim
1. An apparatus for converting a sequence of first encoded voice bits into a sequence of second encoded voice bits, the apparatus comprising:
- a receiver configured to receive first encoded voice bits;
a transcoder connected to receive the first encoded voice bits from the receiver and operable to;
divide the first encoded voice bits into one or more received frames, with each received frame containing multiple ones of the first encoded voice bits,compute first parameter bits for at least one of the received frames by to applying error control decoding to one or more of the encoded voice bits contained in the received frame,compute speech parameters from the first parameter bits,quantize the speech parameters to produce second parameter bits,determine whether the at least one of the received frames is invalid,if the at least one of the received frames is invalid, substitute invalid frame bits for the second parameter bits,form a transmission frame by applying error control encoding to one or more of the second parameter bits or the invalid frame bits, andinclude the transmission frame in second encoded voice bits; and
a transmitted connected to receive the second encoded voice bits from the transcoder and to transmit the second encoded voice bits.
1 Assignment
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Accused Products
Abstract
First encoded voice bits are transcoded into second encoded voice bits by dividing the first encoded voice bits into one or more received frames, with each received frame containing multiple ones of the first encoded voice bits. First parameter bits for at least one of the received frames are generated by applying error control decoding to one or more of the encoded voice bits contained in the received frame, speech parameters are computed from the first parameter bits, and the speech parameters are quantized to produce second parameter bits. Finally, a transmission frame is formed by applying error control encoding to one or more of the second parameter bits, and the transmission frame is included in the second encoded voice bits.
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Citations
22 Claims
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1. An apparatus for converting a sequence of first encoded voice bits into a sequence of second encoded voice bits, the apparatus comprising:
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a receiver configured to receive first encoded voice bits; a transcoder connected to receive the first encoded voice bits from the receiver and operable to; divide the first encoded voice bits into one or more received frames, with each received frame containing multiple ones of the first encoded voice bits, compute first parameter bits for at least one of the received frames by to applying error control decoding to one or more of the encoded voice bits contained in the received frame, compute speech parameters from the first parameter bits, quantize the speech parameters to produce second parameter bits, determine whether the at least one of the received frames is invalid, if the at least one of the received frames is invalid, substitute invalid frame bits for the second parameter bits, form a transmission frame by applying error control encoding to one or more of the second parameter bits or the invalid frame bits, and include the transmission frame in second encoded voice bits; and a transmitted connected to receive the second encoded voice bits from the transcoder and to transmit the second encoded voice bits. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A transcoder operable to convert a sequence of first encoded voice bits into a sequence of second encoded voice bits by:
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dividing the sequence of first voice bits into one or more input frames, with each of the input frames containing multiple ones of the first voice bits; reconstructing speech parameters for one or more of the input frames, wherein; the transcoder stores the speech parameters reconstructed for a previous frame and uses the stored speech parameters reconstructed for a previous frame during reconstruction of the speech parameters for a later frame, the speech parameters include a set of spectral magnitude parameters, and the transcoder reconstructs spectral magnitude parameters for the later frame by; computing a set of predicted magnitudes from spectral magnitude parameters stored from the previous frame; reconstructing spectral magnitude prediction residuals from the later frame; and combining the predicted magnitudes with the spectral magnitude prediction residuals to form the spectral magnitude parameters for the later frame; processing the speech parameters to produce an output frame of bits; and combining one or more of the output frames to form a sequence of second encoded voice bits. - View Dependent Claims (18, 19, 20, 21, 22)
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Specification