Interoperable vocoder
First Claim
1. A method of encoding a sequence of digital speech samples into a bit stream, the method comprising:
- dividing the digital speech samples into one or more frames;
computing model parameters for multiple frames, the model parameters including at least a first parameter conveying pitch information;
determining the voicing state of a frame;
modifying the first parameter conveying pitch information to designate the determined voicing state of the frame if the determined voicing state of the frame is equal to one of a set of reserved voicing states; and
quantizing the model parameters to generate quantizer bits which are used to produce the bit stream.
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Accused Products
Abstract
Encoding a sequence of digital speech samples into a bit stream includes dividing the digital speech samples into one or more frames and computing a set of model parameters for the frames. The set of model parameters includes at least a first parameter conveying pitch information. The voicing state of a frame is determined and the first parameter conveying pitch information is modified to designate the determined voicing state of the frame, if the determined voicing state of the frame is equal to one of a set of reserved voicing states. The model parameters are quantized to generate quantizer bits which are used to produce the bit stream.
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Citations
58 Claims
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1. A method of encoding a sequence of digital speech samples into a bit stream, the method comprising:
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dividing the digital speech samples into one or more frames;
computing model parameters for multiple frames, the model parameters including at least a first parameter conveying pitch information;
determining the voicing state of a frame;
modifying the first parameter conveying pitch information to designate the determined voicing state of the frame if the determined voicing state of the frame is equal to one of a set of reserved voicing states; and
quantizing the model parameters to generate quantizer bits which are used to produce the bit stream. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A method of encoding a sequence of digital speech samples into a bit stream, the method comprising:
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dividing the digital speech samples into one or more frames;
determining whether the digital speech samples for a frame correspond to a tone signal; and
computing model parameters for multiple frames, the model parameters including at least a first parameter representing the pitch and spectral parameters representing the spectral magnitude at harmonic multiples of the pitch;
if the digital speech samples for a frame are determined to correspond to a tone signal, selecting the pitch parameter and the spectral parameters to approximate the detected tone signal; and
quantizing the model parameters to generate quantizer bits which are used to produce the bit stream. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27)
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28. A method of decoding digital speech samples from a sequence of bits, the method comprising:
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dividing the sequence of bits into individual frames, each frame containing multiple bits;
forming quantizer values from a frame of bits, the formed quantizer values including at least a first quantizer value representing the pitch and a second quantizer value representing the voicing state;
determining if the first and second quantizer values belong to a set of reserved quantizer values;
reconstructing speech model parameters for a frame from the quantizer values, the speech model parameters representing the voicing state of the frame being reconstructed from the first quantizer value representing the pitch if the first and second quantizer values are determined to belong to the set of reserved quantizer values; and
computing a set of digital speech samples from the reconstructed speech model parameters. - View Dependent Claims (29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47)
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48. A method of decoding digital speech samples from a sequence of bits, the method comprising:
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dividing the sequence of bits into individual frames that each contain multiple bits;
reconstructing speech model parameters from a frame of bits, the reconstructed speech model parameters for a frame including one or more spectral parameters representing the spectral magnitude information for the frame;
determining from the reconstructed speech model parameters whether the frame represents a tone signal;
modifying the spectral parameters if the frame represents a tone signal, such that the modified spectral parameters better represent the spectral magnitude information of the determined tone signal; and
generating digital speech samples from the reconstructed speech model parameters and the modified spectral parameters. - View Dependent Claims (49, 50, 51, 52, 53, 54, 55, 56, 57, 58)
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Specification