Signed-off-by: Niels Möller <[email protected]>
---
libavcodec/dcadata.h | 30 +++++++++++++++++++++++++++++-
1 file changed, 29 insertions(+), 1 deletion(-)
diff --git a/libavcodec/dcadata.h b/libavcodec/dcadata.h
index 28c40cf..24ae4ef 100644
--- a/libavcodec/dcadata.h
+++ b/libavcodec/dcadata.h
@@ -7305,7 +7305,22 @@ DECLARE_ALIGNED(16, static const float,
fir_32bands_nonperfect)[] =
+1.390191784E-007
};
-/* pre-scale lfe fir coefficients */
+/* pre-scale lfe fir coefficients
+
+ Permuted compared to table D.8 in the spec. First, the table in the
+ spec has twice the number of coefficients, but they are reflected,
+ T[i] = T[511-i]. Furthermore, the indices are permuted, so that
+
+ lfe_fir_64[8 * k + j] = T[64*j + k]
+
+ for 0 <= k < 32 and 0 <= j < 8. (This corresponds to adding a
+ leading zero to the 8-bit index, and rotating it right by 3 bits as
+ a 9-bit field). Values with j >= 4 can be reflected, as
+
+ lfe_fir_64[8 * k + j] = T[64*(7-j) + (63-k)]
+
+ so all values in T get included. */
+
#define SCALE(c) ((c) / (256.0f * 32768.0f))
DECLARE_ALIGNED(16, static const float, lfe_fir_64)[] =
{
@@ -7439,6 +7454,19 @@ DECLARE_ALIGNED(16, static const float, lfe_fir_64)[] =
SCALE(3.165979683399200e-2), SCALE(1.527829794213176e-3),
};
+/* Permuted compared to table D.8 in the spec. First, the table in the
+ spec has twice the number of coefficients, but they are reflected,
+ T[i] = T[511-i]. Furthermore, the indices are permuted, so that
+
+ lfe_fir_128[4 * k + j] = T[128*j + k]
+
+ for 0 <= k < 64 and 0 <= j < 4. Values with j >= 2 can be
+ reflected, as
+
+ lfe_fir_128[4 * k + j] = T[128*(3-j) + (127-k)]
+
+ so all values in T get included. */
+
DECLARE_ALIGNED(16, static const float, lfe_fir_128)[] =
{
SCALE(0.00053168571), SCALE(0.15878495574), SCALE(0.68603444099),
SCALE(0.15492856503),
--
1.8.3.2
--
Niels Möller. PGP-encrypted email is preferred. Keyid C0B98E26.
Internet email is subject to wholesale government surveillance.
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