static void decode(RA288Context *ractx, float gain, int cb_coef) { int i, j; double sumsum; float sum, buffer[5]; memmove(ractx->sp_block + 5, ractx->sp_block, 36*sizeof(*ractx->sp_block)); for (i=4; i >= 0; i--) ractx->sp_block[i] = -scalar_product_float(ractx->sp_block + i + 1, ractx->sp_lpc, 36); /* block 46 of G.728 spec */ sum = 32. - scalar_product_float(ractx->gain_lpc, ractx->gain_block, 10); /* block 47 of G.728 spec */ sum = av_clipf(sum, 0, 60); /* block 48 of G.728 spec */ sumsum = exp(sum * 0.1151292546497) * gain; /* pow(10.0,sum/20)*gain */ for (i=0; i < 5; i++) buffer[i] = codetable[cb_coef][i] * sumsum; sum = scalar_product_float(buffer, buffer, 5) / 5; sum = FFMAX(sum, 1); /* shift and store */ memmove(ractx->gain_block, ractx->gain_block - 1, 10 * sizeof(*ractx->gain_block)); *ractx->gain_block = 10 * log10(sum) - 32; for (i=1; i < 5; i++) for (j=i-1; j >= 0; j--) buffer[i] -= ractx->sp_lpc[i-j-1] * buffer[j]; /* output */ for (i=0; i < 5; i++) ractx->sp_block[4-i] = av_clipf(ractx->sp_block[4-i] + buffer[i], -4095, 4095); }