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-rw-r--r--plugins/demac/libdemac/predictor.c271
1 files changed, 271 insertions, 0 deletions
diff --git a/plugins/demac/libdemac/predictor.c b/plugins/demac/libdemac/predictor.c
new file mode 100644
index 00000000..7d914b5f
--- /dev/null
+++ b/plugins/demac/libdemac/predictor.c
@@ -0,0 +1,271 @@
+/*
+
+libdemac - A Monkey's Audio decoder
+
+$Id: predictor.c 19375 2008-12-09 23:20:59Z amiconn $
+
+Copyright (C) Dave Chapman 2007
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program; if not, write to the Free Software
+Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110, USA
+
+*/
+
+#include <inttypes.h>
+#include <string.h>
+
+#include "parser.h"
+#include "predictor.h"
+#include "demac_config.h"
+
+/* Return 0 if x is zero, -1 if x is positive, 1 if x is negative */
+#define SIGN(x) (x) ? (((x) > 0) ? -1 : 1) : 0
+
+static const int32_t initial_coeffs[4] = {
+ 360, 317, -109, 98
+};
+
+#define YDELAYA (18 + PREDICTOR_ORDER*4)
+#define YDELAYB (18 + PREDICTOR_ORDER*3)
+#define XDELAYA (18 + PREDICTOR_ORDER*2)
+#define XDELAYB (18 + PREDICTOR_ORDER)
+
+#define YADAPTCOEFFSA (18)
+#define XADAPTCOEFFSA (14)
+#define YADAPTCOEFFSB (10)
+#define XADAPTCOEFFSB (5)
+
+void init_predictor_decoder(struct predictor_t* p)
+{
+ /* Zero the history buffers */
+ memset(p->historybuffer, 0, PREDICTOR_SIZE * sizeof(int32_t));
+ p->buf = p->historybuffer;
+
+ /* Initialise and zero the co-efficients */
+ memcpy(p->YcoeffsA, initial_coeffs, sizeof(initial_coeffs));
+ memcpy(p->XcoeffsA, initial_coeffs, sizeof(initial_coeffs));
+ memset(p->YcoeffsB, 0, sizeof(p->YcoeffsB));
+ memset(p->XcoeffsB, 0, sizeof(p->XcoeffsB));
+
+ p->YfilterA = 0;
+ p->YfilterB = 0;
+ p->YlastA = 0;
+
+ p->XfilterA = 0;
+ p->XfilterB = 0;
+ p->XlastA = 0;
+}
+
+#if !defined(CPU_ARM) && !defined(CPU_COLDFIRE)
+void ICODE_ATTR_DEMAC predictor_decode_stereo(struct predictor_t* p,
+ int32_t* decoded0,
+ int32_t* decoded1,
+ int count)
+{
+ int32_t predictionA, predictionB;
+
+ while (LIKELY(count--))
+ {
+ /* Predictor Y */
+ p->buf[YDELAYA] = p->YlastA;
+ p->buf[YADAPTCOEFFSA] = SIGN(p->buf[YDELAYA]);
+
+ p->buf[YDELAYA-1] = p->buf[YDELAYA] - p->buf[YDELAYA-1];
+ p->buf[YADAPTCOEFFSA-1] = SIGN(p->buf[YDELAYA-1]);
+
+ predictionA = (p->buf[YDELAYA] * p->YcoeffsA[0]) +
+ (p->buf[YDELAYA-1] * p->YcoeffsA[1]) +
+ (p->buf[YDELAYA-2] * p->YcoeffsA[2]) +
+ (p->buf[YDELAYA-3] * p->YcoeffsA[3]);
+
+ /* Apply a scaled first-order filter compression */
+ p->buf[YDELAYB] = p->XfilterA - ((p->YfilterB * 31) >> 5);
+ p->buf[YADAPTCOEFFSB] = SIGN(p->buf[YDELAYB]);
+ p->YfilterB = p->XfilterA;
+
+ p->buf[YDELAYB-1] = p->buf[YDELAYB] - p->buf[YDELAYB-1];
+ p->buf[YADAPTCOEFFSB-1] = SIGN(p->buf[YDELAYB-1]);
+
+ predictionB = (p->buf[YDELAYB] * p->YcoeffsB[0]) +
+ (p->buf[YDELAYB-1] * p->YcoeffsB[1]) +
+ (p->buf[YDELAYB-2] * p->YcoeffsB[2]) +
+ (p->buf[YDELAYB-3] * p->YcoeffsB[3]) +
+ (p->buf[YDELAYB-4] * p->YcoeffsB[4]);
+
+ p->YlastA = *decoded0 + ((predictionA + (predictionB >> 1)) >> 10);
+ p->YfilterA = p->YlastA + ((p->YfilterA * 31) >> 5);
+
+ /* Predictor X */
+
+ p->buf[XDELAYA] = p->XlastA;
+ p->buf[XADAPTCOEFFSA] = SIGN(p->buf[XDELAYA]);
+ p->buf[XDELAYA-1] = p->buf[XDELAYA] - p->buf[XDELAYA-1];
+ p->buf[XADAPTCOEFFSA-1] = SIGN(p->buf[XDELAYA-1]);
+
+ predictionA = (p->buf[XDELAYA] * p->XcoeffsA[0]) +
+ (p->buf[XDELAYA-1] * p->XcoeffsA[1]) +
+ (p->buf[XDELAYA-2] * p->XcoeffsA[2]) +
+ (p->buf[XDELAYA-3] * p->XcoeffsA[3]);
+
+ /* Apply a scaled first-order filter compression */
+ p->buf[XDELAYB] = p->YfilterA - ((p->XfilterB * 31) >> 5);
+ p->buf[XADAPTCOEFFSB] = SIGN(p->buf[XDELAYB]);
+ p->XfilterB = p->YfilterA;
+ p->buf[XDELAYB-1] = p->buf[XDELAYB] - p->buf[XDELAYB-1];
+ p->buf[XADAPTCOEFFSB-1] = SIGN(p->buf[XDELAYB-1]);
+
+ predictionB = (p->buf[XDELAYB] * p->XcoeffsB[0]) +
+ (p->buf[XDELAYB-1] * p->XcoeffsB[1]) +
+ (p->buf[XDELAYB-2] * p->XcoeffsB[2]) +
+ (p->buf[XDELAYB-3] * p->XcoeffsB[3]) +
+ (p->buf[XDELAYB-4] * p->XcoeffsB[4]);
+
+ p->XlastA = *decoded1 + ((predictionA + (predictionB >> 1)) >> 10);
+ p->XfilterA = p->XlastA + ((p->XfilterA * 31) >> 5);
+
+ if (LIKELY(*decoded0 != 0))
+ {
+ if (*decoded0 > 0)
+ {
+ p->YcoeffsA[0] -= p->buf[YADAPTCOEFFSA];
+ p->YcoeffsA[1] -= p->buf[YADAPTCOEFFSA-1];
+ p->YcoeffsA[2] -= p->buf[YADAPTCOEFFSA-2];
+ p->YcoeffsA[3] -= p->buf[YADAPTCOEFFSA-3];
+
+ p->YcoeffsB[0] -= p->buf[YADAPTCOEFFSB];
+ p->YcoeffsB[1] -= p->buf[YADAPTCOEFFSB-1];
+ p->YcoeffsB[2] -= p->buf[YADAPTCOEFFSB-2];
+ p->YcoeffsB[3] -= p->buf[YADAPTCOEFFSB-3];
+ p->YcoeffsB[4] -= p->buf[YADAPTCOEFFSB-4];
+ }
+ else
+ {
+ p->YcoeffsA[0] += p->buf[YADAPTCOEFFSA];
+ p->YcoeffsA[1] += p->buf[YADAPTCOEFFSA-1];
+ p->YcoeffsA[2] += p->buf[YADAPTCOEFFSA-2];
+ p->YcoeffsA[3] += p->buf[YADAPTCOEFFSA-3];
+
+ p->YcoeffsB[0] += p->buf[YADAPTCOEFFSB];
+ p->YcoeffsB[1] += p->buf[YADAPTCOEFFSB-1];
+ p->YcoeffsB[2] += p->buf[YADAPTCOEFFSB-2];
+ p->YcoeffsB[3] += p->buf[YADAPTCOEFFSB-3];
+ p->YcoeffsB[4] += p->buf[YADAPTCOEFFSB-4];
+ }
+ }
+
+ *(decoded0++) = p->YfilterA;
+
+ if (LIKELY(*decoded1 != 0))
+ {
+ if (*decoded1 > 0)
+ {
+ p->XcoeffsA[0] -= p->buf[XADAPTCOEFFSA];
+ p->XcoeffsA[1] -= p->buf[XADAPTCOEFFSA-1];
+ p->XcoeffsA[2] -= p->buf[XADAPTCOEFFSA-2];
+ p->XcoeffsA[3] -= p->buf[XADAPTCOEFFSA-3];
+
+ p->XcoeffsB[0] -= p->buf[XADAPTCOEFFSB];
+ p->XcoeffsB[1] -= p->buf[XADAPTCOEFFSB-1];
+ p->XcoeffsB[2] -= p->buf[XADAPTCOEFFSB-2];
+ p->XcoeffsB[3] -= p->buf[XADAPTCOEFFSB-3];
+ p->XcoeffsB[4] -= p->buf[XADAPTCOEFFSB-4];
+ }
+ else
+ {
+ p->XcoeffsA[0] += p->buf[XADAPTCOEFFSA];
+ p->XcoeffsA[1] += p->buf[XADAPTCOEFFSA-1];
+ p->XcoeffsA[2] += p->buf[XADAPTCOEFFSA-2];
+ p->XcoeffsA[3] += p->buf[XADAPTCOEFFSA-3];
+
+ p->XcoeffsB[0] += p->buf[XADAPTCOEFFSB];
+ p->XcoeffsB[1] += p->buf[XADAPTCOEFFSB-1];
+ p->XcoeffsB[2] += p->buf[XADAPTCOEFFSB-2];
+ p->XcoeffsB[3] += p->buf[XADAPTCOEFFSB-3];
+ p->XcoeffsB[4] += p->buf[XADAPTCOEFFSB-4];
+ }
+ }
+
+ *(decoded1++) = p->XfilterA;
+
+ /* Combined */
+ p->buf++;
+
+ /* Have we filled the history buffer? */
+ if (UNLIKELY(p->buf == p->historybuffer + PREDICTOR_HISTORY_SIZE)) {
+ memmove(p->historybuffer, p->buf,
+ PREDICTOR_SIZE * sizeof(int32_t));
+ p->buf = p->historybuffer;
+ }
+ }
+}
+
+void ICODE_ATTR_DEMAC predictor_decode_mono(struct predictor_t* p,
+ int32_t* decoded0,
+ int count)
+{
+ int32_t predictionA, currentA, A;
+
+ currentA = p->YlastA;
+
+ while (LIKELY(count--))
+ {
+ A = *decoded0;
+
+ p->buf[YDELAYA] = currentA;
+ p->buf[YDELAYA-1] = p->buf[YDELAYA] - p->buf[YDELAYA-1];
+
+ predictionA = (p->buf[YDELAYA] * p->YcoeffsA[0]) +
+ (p->buf[YDELAYA-1] * p->YcoeffsA[1]) +
+ (p->buf[YDELAYA-2] * p->YcoeffsA[2]) +
+ (p->buf[YDELAYA-3] * p->YcoeffsA[3]);
+
+ currentA = A + (predictionA >> 10);
+
+ p->buf[YADAPTCOEFFSA] = SIGN(p->buf[YDELAYA]);
+ p->buf[YADAPTCOEFFSA-1] = SIGN(p->buf[YDELAYA-1]);
+
+ if (LIKELY(A != 0))
+ {
+ if (A > 0)
+ {
+ p->YcoeffsA[0] -= p->buf[YADAPTCOEFFSA];
+ p->YcoeffsA[1] -= p->buf[YADAPTCOEFFSA-1];
+ p->YcoeffsA[2] -= p->buf[YADAPTCOEFFSA-2];
+ p->YcoeffsA[3] -= p->buf[YADAPTCOEFFSA-3];
+ }
+ else
+ {
+ p->YcoeffsA[0] += p->buf[YADAPTCOEFFSA];
+ p->YcoeffsA[1] += p->buf[YADAPTCOEFFSA-1];
+ p->YcoeffsA[2] += p->buf[YADAPTCOEFFSA-2];
+ p->YcoeffsA[3] += p->buf[YADAPTCOEFFSA-3];
+ }
+ }
+
+ p->buf++;
+
+ /* Have we filled the history buffer? */
+ if (UNLIKELY(p->buf == p->historybuffer + PREDICTOR_HISTORY_SIZE)) {
+ memmove(p->historybuffer, p->buf,
+ PREDICTOR_SIZE * sizeof(int32_t));
+ p->buf = p->historybuffer;
+ }
+
+ p->YfilterA = currentA + ((p->YfilterA * 31) >> 5);
+ *(decoded0++) = p->YfilterA;
+ }
+
+ p->YlastA = currentA;
+}
+#endif
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