diff options
| -rw-r--r-- | libAACdec/src/usacdec_lpc.cpp | 14 |
1 files changed, 6 insertions, 8 deletions
diff --git a/libAACdec/src/usacdec_lpc.cpp b/libAACdec/src/usacdec_lpc.cpp index 440fa87..278afbe 100644 --- a/libAACdec/src/usacdec_lpc.cpp +++ b/libAACdec/src/usacdec_lpc.cpp @@ -1170,6 +1170,9 @@ void E_LPC_f_lsp_a_conversion(FIXP_LPC *lsp, FIXP_LPC *a, INT *a_exp) { /*-----------------------------------------------------* * Multiply F1(z) by (1+z^-1) and F2(z) by (1-z^-1) * *-----------------------------------------------------*/ + scaleValues(f1, NC + 1, -2); + scaleValues(f2, NC + 1, -2); + for (i = NC; i > 0; i--) { f1[i] += f1[i - 1]; f2[i] -= f2[i - 1]; @@ -1178,13 +1181,8 @@ void E_LPC_f_lsp_a_conversion(FIXP_LPC *lsp, FIXP_LPC *a, INT *a_exp) { FIXP_DBL aDBL[M_LP_FILTER_ORDER]; for (i = 1, k = M_LP_FILTER_ORDER - 1; i <= NC; i++, k--) { - FIXP_DBL tmp1, tmp2; - - tmp1 = f1[i] >> 1; - tmp2 = f2[i] >> 1; - - aDBL[i - 1] = (tmp1 + tmp2); - aDBL[k] = (tmp1 - tmp2); + aDBL[i - 1] = f1[i] + f2[i]; + aDBL[k] = f1[i] - f2[i]; } int headroom_a = getScalefactor(aDBL, M_LP_FILTER_ORDER); @@ -1193,5 +1191,5 @@ void E_LPC_f_lsp_a_conversion(FIXP_LPC *lsp, FIXP_LPC *a, INT *a_exp) { a[i] = FX_DBL2FX_LPC(aDBL[i] << headroom_a); } - *a_exp = 8 - headroom_a; + *a_exp = SF_F + (2 - 1) - headroom_a; } |