/* * G.723.1 compatible decoder * Copyright (c) 2006 Benjamin Larsson * Copyright (c) 2010 Mohamed Naufal Basheer * * This file is part of FFmpeg. * * FFmpeg is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * FFmpeg is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with FFmpeg; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ #include <stdint.h> #include "libavutil/common.h" #include "acelp_vectors.h" #include "avcodec.h" #include "celp_math.h" #include "g723_1.h" int ff_g723_1_scale_vector(int16_t *dst, const int16_t *vector, int length) { int bits, max = 0; int i; for (i = 0; i < length; i++) max |= FFABS(vector[i]); bits= 14 - av_log2_16bit(max); bits= FFMAX(bits, 0); for (i = 0; i < length; i++) dst[i] = (vector[i] * (1 << bits)) >> 3; return bits - 3; } int ff_g723_1_normalize_bits(int num, int width) { return width - av_log2(num) - 1; } int ff_g723_1_dot_product(const int16_t *a, const int16_t *b, int length) { int sum = ff_dot_product(a, b, length); return av_sat_add32(sum, sum); } void ff_g723_1_get_residual(int16_t *residual, int16_t *prev_excitation, int lag) { int offset = PITCH_MAX - PITCH_ORDER / 2 - lag; int i; residual[0] = prev_excitation[offset]; residual[1] = prev_excitation[offset + 1]; offset += 2; for (i = 2; i < SUBFRAME_LEN + PITCH_ORDER - 1; i++) residual[i] = prev_excitation[offset + (i - 2) % lag]; } void ff_g723_1_gen_dirac_train(int16_t *buf, int pitch_lag) { int16_t vector[SUBFRAME_LEN]; int i, j; memcpy(vector, buf, SUBFRAME_LEN * sizeof(*vector)); for (i = pitch_lag; i < SUBFRAME_LEN; i += pitch_lag) { for (j = 0; j < SUBFRAME_LEN - i; j++) buf[i + j] += vector[j]; } } void ff_g723_1_gen_acb_excitation(int16_t *vector, int16_t *prev_excitation, int pitch_lag, G723_1_Subframe *subfrm, enum Rate cur_rate) { int16_t residual[SUBFRAME_LEN + PITCH_ORDER - 1]; const int16_t *cb_ptr; int lag = pitch_lag + subfrm->ad_cb_lag - 1; int i; int sum; ff_g723_1_get_residual(residual, prev_excitation, lag); /* Select quantization table */ if (cur_rate == RATE_6300 && pitch_lag < SUBFRAME_LEN - 2) { cb_ptr = adaptive_cb_gain85; } else cb_ptr = adaptive_cb_gain170; /* Calculate adaptive vector */ cb_ptr += subfrm->ad_cb_gain * 20; for (i = 0; i < SUBFRAME_LEN; i++) { sum = ff_dot_product(residual + i, cb_ptr, PITCH_ORDER); vector[i] = av_sat_dadd32(1 << 15, av_sat_add32(sum, sum)) >> 16; } } /** * Convert LSP frequencies to LPC coefficients. * * @param lpc buffer for LPC coefficients */ static void lsp2lpc(int16_t *lpc) { int f1[LPC_ORDER / 2 + 1]; int f2[LPC_ORDER / 2 + 1]; int i, j; /* Calculate negative cosine */ for (j = 0; j < LPC_ORDER; j++) { int index = (lpc[j] >> 7) & 0x1FF; int offset = lpc[j] & 0x7f; int temp1 = cos_tab[index] * (1 << 16); int temp2 = (cos_tab[index + 1] - cos_tab[index]) * (((offset << 8) + 0x80) << 1); lpc[j] = -(av_sat_dadd32(1 << 15, temp1 + temp2) >> 16); } /* * Compute sum and difference polynomial coefficients * (bitexact alternative to lsp2poly() in lsp.c) */ /* Initialize with values in Q28 */ f1[0] = 1 << 28; f1[1] = (lpc[0] + lpc[2]) * (1 << 14); f1[2] = lpc[0] * lpc[2] + (2 << 28); f2[0] = 1 << 28; f2[1] = (lpc[1] + lpc[3]) * (1 << 14); f2[2] = lpc[1] * lpc[3] + (2 << 28); /* * Calculate and scale the coefficients by 1/2 in * each iteration for a final scaling factor of Q25 */ for (i = 2; i < LPC_ORDER / 2; i++) { f1[i + 1] = av_clipl_int32(f1[i - 1] + (int64_t)MULL2(f1[i], lpc[2 * i])); f2[i + 1] = av_clipl_int32(f2[i - 1] + (int64_t)MULL2(f2[i], lpc[2 * i + 1])); for (j = i; j >= 2; j--) { f1[j] = MULL2(f1[j - 1], lpc[2 * i]) + (f1[j] >> 1) + (f1[j - 2] >> 1); f2[j] = MULL2(f2[j - 1], lpc[2 * i + 1]) + (f2[j] >> 1) + (f2[j - 2] >> 1); } f1[0] >>= 1; f2[0] >>= 1; f1[1] = ((lpc[2 * i] * 65536 >> i) + f1[1]) >> 1; f2[1] = ((lpc[2 * i + 1] * 65536 >> i) + f2[1]) >> 1; } /* Convert polynomial coefficients to LPC coefficients */ for (i = 0; i < LPC_ORDER / 2; i++) { int64_t ff1 = f1[i + 1] + f1[i]; int64_t ff2 = f2[i + 1] - f2[i]; lpc[i] = av_clipl_int32(((ff1 + ff2) * 8) + (1 << 15)) >> 16; lpc[LPC_ORDER - i - 1] = av_clipl_int32(((ff1 - ff2) * 8) + (1 << 15)) >> 16; } } void ff_g723_1_lsp_interpolate(int16_t *lpc, int16_t *cur_lsp, int16_t *prev_lsp) { int i; int16_t *lpc_ptr = lpc; /* cur_lsp * 0.25 + prev_lsp * 0.75 */ ff_acelp_weighted_vector_sum(lpc, cur_lsp, prev_lsp, 4096, 12288, 1 << 13, 14, LPC_ORDER); ff_acelp_weighted_vector_sum(lpc + LPC_ORDER, cur_lsp, prev_lsp, 8192, 8192, 1 << 13, 14, LPC_ORDER); ff_acelp_weighted_vector_sum(lpc + 2 * LPC_ORDER, cur_lsp, prev_lsp, 12288, 4096, 1 << 13, 14, LPC_ORDER); memcpy(lpc + 3 * LPC_ORDER, cur_lsp, LPC_ORDER * sizeof(*lpc)); for (i = 0; i < SUBFRAMES; i++) { lsp2lpc(lpc_ptr); lpc_ptr += LPC_ORDER; } } void ff_g723_1_inverse_quant(int16_t *cur_lsp, int16_t *prev_lsp, uint8_t *lsp_index, int bad_frame) { int min_dist, pred; int i, j, temp, stable; /* Check for frame erasure */ if (!bad_frame) { min_dist = 0x100; pred = 12288; } else { min_dist = 0x200; pred = 23552; lsp_index[0] = lsp_index[1] = lsp_index[2] = 0; } /* Get the VQ table entry corresponding to the transmitted index */ cur_lsp[0] = lsp_band0[lsp_index[0]][0]; cur_lsp[1] = lsp_band0[lsp_index[0]][1]; cur_lsp[2] = lsp_band0[lsp_index[0]][2]; cur_lsp[3] = lsp_band1[lsp_index[1]][0]; cur_lsp[4] = lsp_band1[lsp_index[1]][1]; cur_lsp[5] = lsp_band1[lsp_index[1]][2]; cur_lsp[6] = lsp_band2[lsp_index[2]][0]; cur_lsp[7] = lsp_band2[lsp_index[2]][1]; cur_lsp[8] = lsp_band2[lsp_index[2]][2]; cur_lsp[9] = lsp_band2[lsp_index[2]][3]; /* Add predicted vector & DC component to the previously quantized vector */ for (i = 0; i < LPC_ORDER; i++) { temp = ((prev_lsp[i] - dc_lsp[i]) * pred + (1 << 14)) >> 15; cur_lsp[i] += dc_lsp[i] + temp; } for (i = 0; i < LPC_ORDER; i++) { cur_lsp[0] = FFMAX(cur_lsp[0], 0x180); cur_lsp[LPC_ORDER - 1] = FFMIN(cur_lsp[LPC_ORDER - 1], 0x7e00); /* Stability check */ for (j = 1; j < LPC_ORDER; j++) { temp = min_dist + cur_lsp[j - 1] - cur_lsp[j]; if (temp > 0) { temp >>= 1; cur_lsp[j - 1] -= temp; cur_lsp[j] += temp; } } stable = 1; for (j = 1; j < LPC_ORDER; j++) { temp = cur_lsp[j - 1] + min_dist - cur_lsp[j] - 4; if (temp > 0) { stable = 0; break; } } if (stable) break; } if (!stable) memcpy(cur_lsp, prev_lsp, LPC_ORDER * sizeof(*cur_lsp)); }