1 files changed, 95 insertions, 0 deletions
diff --git a/src/libac3/rematrix.c b/src/libac3/rematrix.c
new file mode 100644
index 000000000..95ce0117c
--- /dev/null
+++ b/src/libac3/rematrix.c
@@ -0,0 +1,95 @@
+/* 
+ *    rematrix.c
+ *
+ *	Copyright (C) Aaron Holtzman - July 1999
+ *
+ *  This file is part of ac3dec, a free Dolby AC-3 stream decoder.
+ *	
+ *  ac3dec 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, or (at your option)
+ *  any later version.
+ *   
+ *  ac3dec 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 GNU Make; see the file COPYING.  If not, write to
+ *  the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. 
+ *
+ *
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif 
+
+#include <stdlib.h>
+#include <stdio.h>
+#include "ac3.h"
+#include "ac3_internal.h"
+
+
+#include "rematrix.h"
+
+
+struct rematrix_band_s
+{
+	uint32_t start;
+	uint32_t end;
+} rematrix_band[] = {
+	{13, 24},
+	{25, 36},
+	{37, 60},
+	{61, 252}
+};
+
+
+/**
+ *
+ **/
+
+inline uint32_t min (uint32_t a, uint32_t b)
+{
+	return (a < b) ? a : b;
+}
+
+
+/**
+ * This routine simply does stereo remartixing for the 2 channel 
+ * stereo mode
+ **/
+
+void rematrix (audblk_t *audblk, stream_samples_t samples)
+{
+	uint32_t num_bands;
+	uint32_t start;
+	uint32_t end;
+	int i,j;
+
+	if (!audblk->cplinu || audblk->cplbegf > 2)
+		num_bands = 4;
+	else if (audblk->cplbegf > 0)
+		num_bands = 3;
+	else
+		num_bands = 2;
+
+	for (i=0; i < num_bands; i++) {
+		if (!audblk->rematflg[i])
+			continue;
+
+		start = rematrix_band[i].start;
+		end = min (rematrix_band[i].end ,12 * audblk->cplbegf + 36);
+	
+		for (j=start;j < end; j++) {
+			float left,right;
+
+			left  = samples[0][j] + samples[1][j];
+			right = samples[0][j] - samples[1][j];
+			samples[0][j] = left;
+			samples[1][j] = right;
+		}
+	}
+}