diff options
| -rw-r--r-- | libAACdec/src/usacdec_acelp.cpp | 23 |
1 files changed, 13 insertions, 10 deletions
diff --git a/libAACdec/src/usacdec_acelp.cpp b/libAACdec/src/usacdec_acelp.cpp index 1ac8c9f..a8dadc0 100644 --- a/libAACdec/src/usacdec_acelp.cpp +++ b/libAACdec/src/usacdec_acelp.cpp @@ -465,7 +465,9 @@ void BuildAdaptiveExcitation( /* Note: code[L_SUBFR] and exc2[L_SUBFR] share the same memory! If exc2[i] is written, code[i] will be destroyed! */ -#define SF (SF_CODE + SF_GAIN_C + 1 - SF_EXC) +#define SF_HEADROOM (1) +#define SF (SF_CODE + SF_GAIN_C + 1 - SF_EXC - SF_HEADROOM) +#define SF_GAIN_P2 (SF_GAIN_P - SF_HEADROOM) int i; FIXP_DBL tmp, cpe, code_smooth_prev, code_smooth; @@ -477,8 +479,8 @@ void BuildAdaptiveExcitation( cpe = (period_fac >> (2 - SF_PFAC)) + FL2FXCONST_DBL(0.25f); /* u'(n) */ - tmp = fMultDiv2(*exc, gain_pit) << (SF_GAIN_P + 1); /* v(0)*g_p */ - *exc++ = tmp + (fMultDiv2(code[0], gain_code) << SF); + tmp = fMultDiv2(*exc, gain_pit) << (SF_GAIN_P2 + 1); /* v(0)*g_p */ + *exc++ = (tmp + (fMultDiv2(code[0], gain_code) << SF)) << SF_HEADROOM; /* u(n) */ code_smooth_prev = fMultDiv2(*code++, gain_code_smoothed) @@ -487,15 +489,15 @@ void BuildAdaptiveExcitation( code_smooth = fMultDiv2(code_i, gain_code_smoothed) << SF; /* c(1) * g_sc */ tmp += code_smooth_prev; /* tmp = v(0)*g_p + c(0)*g_sc */ cpe_code_smooth = fMultDiv2(cpe, code_smooth); - *exc2++ = tmp - cpe_code_smooth; + *exc2++ = (tmp - cpe_code_smooth) << SF_HEADROOM; cpe_code_smooth_prev = fMultDiv2(cpe, code_smooth_prev); i = L_SUBFR - 2; do /* ARM926: 22 cycles per iteration */ { /* u'(n) */ - tmp = fMultDiv2(*exc, gain_pit) << (SF_GAIN_P + 1); - *exc++ = tmp + (fMultDiv2(code_i, gain_code) << SF); + tmp = fMultDiv2(*exc, gain_pit) << (SF_GAIN_P2 + 1); + *exc++ = (tmp + (fMultDiv2(code_i, gain_code) << SF)) << SF_HEADROOM; /* u(n) */ tmp += code_smooth; /* += g_sc * c(i) */ tmp -= cpe_code_smooth_prev; @@ -503,16 +505,17 @@ void BuildAdaptiveExcitation( code_i = *code++; code_smooth = fMultDiv2(code_i, gain_code_smoothed) << SF; cpe_code_smooth = fMultDiv2(cpe, code_smooth); - *exc2++ = tmp - cpe_code_smooth; /* tmp - c_pe * g_sc * c(i+1) */ + *exc2++ = (tmp - cpe_code_smooth) + << SF_HEADROOM; /* tmp - c_pe * g_sc * c(i+1) */ } while (--i != 0); /* u'(n) */ - tmp = fMultDiv2(*exc, gain_pit) << (SF_GAIN_P + 1); - *exc = tmp + (fMultDiv2(code_i, gain_code) << SF); + tmp = fMultDiv2(*exc, gain_pit) << (SF_GAIN_P2 + 1); + *exc = (tmp + (fMultDiv2(code_i, gain_code) << SF)) << SF_HEADROOM; /* u(n) */ tmp += code_smooth; tmp -= cpe_code_smooth_prev; - *exc2++ = tmp; + *exc2++ = tmp << SF_HEADROOM; return; } |