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AssigneeNokia Mobile Phones Ltd.
InventorsAri Heikkinen, Vesa T. Ruoppila, Samuli Pietilä
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A method and apparatus for coding successive pitch periods of a speech signal. Based on a priori knowledge of statistical properties of successive speech periods, a shaped lattice structure is designed to cover the most probable points in the pitch space. The codebook index search starts with finding an open-loop estimate in the pitch space considering all dimensions and refining the open-loop estimate in a closed-loop search separately in each dimension based on the shaped lattice structure. The closed-loop search for the first subframe is for obtaining an absolute pitch period or a delta pitch while the closed-loop search for each of the other subframes is for obtaining a delta pitch for the respective subframe.
A method of coding a sound signal in a plurality of signal frames each having a pitch period indicative of the sound signal in the respective signal frame, wherein each signal frame comprises a plurality of signal segments each representing a dimension in a pitch space, and the sound signal in each of the signal segments is characterized by a pitch value, and wherein the pitch values are representable by a point distribution pattern characteristic of the sound signal in a lattice structure for defining codebook indices in the pitch space, said method comprising the steps of:
An apparatus for encoding a sound signal in a plurality of signal frames each having a pitch period indicative of the sound signal in the respective signal frame, wherein each signal frame comprises a plurality of signal segments each representing a dimension in a pitch space, and the sound signal in each of the signal segments is characterized by a pitch value, and wherein the pitch values are representable by a point distribution pattern characteristic of the sound signal in a lattice structure for defining codebook indices in the pitch space, and the lattice structure is shaped based on the point distribution pattern for defining a shaped lattice structure, said apparatus comprising:
A system for coding a sound signal in a plurality of signal frames each having a pitch period indicative of the sound signal in the respective signal frame, wherein each signal frame comprises a plurality of signal segments each representing a dimension in a pitch space, and the sound signal in each of the signal segments is characterized by a pitch value, and wherein the pitch values are representable by a point distribution pattern characteristic of the sound signal in a lattice structure for defining codebook indices in the pitch space, and the lattice structure is shaped based on the point distribution pattern for defining a shaped lattice structure, said system comprising:
Dependencies are inferred from the claim text.