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authorAndree Buschmann <AndreeBuschmann@t-online.de>2011-03-20 15:57:38 +0000
committerAndree Buschmann <AndreeBuschmann@t-online.de>2011-03-20 15:57:38 +0000
commite9c5190de7e1b550ea9d6b5293e21cd53e8037be (patch)
tree11724312bc023b2ecf810d19bbd1babcadc8a7b5 /apps/codecs/libfaad
parentd1098f31004e8a751f304062a6252baacb83b4f9 (diff)
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Headroom in AAC SBR HF-generator's fixed point implementation of autocorrelation was too small. Fixes FS#12019.
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@29622 a1c6a512-1295-4272-9138-f99709370657
Diffstat (limited to 'apps/codecs/libfaad')
-rw-r--r--apps/codecs/libfaad/sbr_hfgen.c12
1 files changed, 6 insertions, 6 deletions
diff --git a/apps/codecs/libfaad/sbr_hfgen.c b/apps/codecs/libfaad/sbr_hfgen.c
index 1e32eb2..bdc7d5a 100644
--- a/apps/codecs/libfaad/sbr_hfgen.c
+++ b/apps/codecs/libfaad/sbr_hfgen.c
@@ -186,13 +186,13 @@ typedef struct
real_t det;
} acorr_coef;
-/* Within auto_correlation(...) a pre-shift of >>2 is needed to avoid overflow
- * when multiply-adding the FRACT-variables -- FRACT part is 31 bits. After the
- * calculation has been finished the result 'ac->det' needs to be
- * post-shifted by <<(4*2). This pre-/post-shifting is needed for FIXED_POINT
- * only. */
+/* Within auto_correlation(...) a pre-shift of >>ACDET_EXP is needed to avoid
+ * overflow when multiply-adding the FRACT-variables -- FRACT part is 31 bits.
+ * After the calculation has been finished the result 'ac->det' needs to be
+ * post-shifted by <<(4*ACDET_EXP). This pre-/post-shifting is needed for
+ * FIXED_POINT only. */
#ifdef FIXED_POINT
-#define ACDET_EXP 2
+#define ACDET_EXP 3
#define ACDET_PRE(A) (A)>>ACDET_EXP
#define ACDET_POST(A) (A)<<(4*ACDET_EXP)
#else