/* * Copyright (c) 2011 The WebRTC project authors. All Rights Reserved. * * Use of this source code is governed by a BSD-style license * that can be found in the LICENSE file in the root of the source * tree. An additional intellectual property rights grant can be found * in the file PATENTS. All contributing project authors may * be found in the AUTHORS file in the root of the source tree. */ /****************************************************************** iLBC Speech Coder ANSI-C Source Code WebRtcIlbcfix_LpcEncode.c ******************************************************************/ #include "defines.h" #include "simple_lpc_analysis.h" #include "simple_interpolate_lsf.h" #include "simple_lsf_quant.h" #include "lsf_check.h" #include "constants.h" /*----------------------------------------------------------------* * lpc encoder *---------------------------------------------------------------*/ void WebRtcIlbcfix_LpcEncode( int16_t *syntdenum, /* (i/o) synthesis filter coefficients before/after encoding */ int16_t *weightdenum, /* (i/o) weighting denumerator coefficients before/after encoding */ int16_t *lsf_index, /* (o) lsf quantization index */ int16_t *data, /* (i) Speech to do LPC analysis on */ iLBC_Enc_Inst_t *iLBCenc_inst /* (i/o) the encoder state structure */ ) { /* Stack based */ int16_t lsf[LPC_FILTERORDER * LPC_N_MAX]; int16_t lsfdeq[LPC_FILTERORDER * LPC_N_MAX]; /* Calculate LSF's from the input speech */ WebRtcIlbcfix_SimpleLpcAnalysis(lsf, data, iLBCenc_inst); /* Quantize the LSF's */ WebRtcIlbcfix_SimpleLsfQ(lsfdeq, lsf_index, lsf, iLBCenc_inst->lpc_n); /* Stableize the LSF's if needed */ WebRtcIlbcfix_LsfCheck(lsfdeq, LPC_FILTERORDER, iLBCenc_inst->lpc_n); /* Calculate the synthesis and weighting filter coefficients from the optimal LSF and the dequantized LSF */ WebRtcIlbcfix_SimpleInterpolateLsf(syntdenum, weightdenum, lsf, lsfdeq, iLBCenc_inst->lsfold, iLBCenc_inst->lsfdeqold, LPC_FILTERORDER, iLBCenc_inst); return; }