Patent ID: 7363218
Filing Date: 2008-04-22
Classification: G10L

Abstract:
1. An apparatus for mapping CELP parameters between a source codec and a destination codec, the apparatus comprising: an LSP mapping module; an adaptive codebook mapping module coupled to the LSP mapping module; a fixed codebook mapping module coupled to the LSP mapping module and the adaptive codebook mapping module; wherein the LSP mapping module comprises: an LP overflow module configured to process information associated with a plurality of interpolated LSP parameters and generate an overflow signal based on at least information associated with the plurality of interpolated LSP parameters; an LSP parameter modification module configured to modify at least one frequency of at least one of the plurality of interpolated LSP parameters in response to the overflow signal; wherein the adaptive codebook mapping module comprises a first pitch gain codebook, the first pitch gain codebook including a first plurality of entries, each of the first plurality of entries including a plurality of terms and a plurality of sums associated with the plurality of terms; wherein the fixed codebook mapping module comprises: a first target processing module configured to process a first target signal and generate a first modified target signal; a pulse search module configured to locate a first plurality of pulse positions and signs for a plurality of pulses in a subframe based on at least information associated with the first modified target signal; a fixed codebook gain estimation module configured to estimate a fixed codebook gain for the subframe based on at least information associated with the first plurality of pulse positions and signs; a pulse position searching module configured to receive the first modified target signal, an impulse response signal and the estimated fixed codebook gain and to output a second plurality of pulse positions and signs for the plurality of pulses.