dts decoder using libdca

1 files changed, 694 insertions, 0 deletions

diff --git a/plugins/dca/downmix.c b/plugins/dca/downmix.c
new file mode 100644
index 00000000..ff02127f
--- /dev/null
+++ b/plugins/dca/downmix.c
@@ -0,0 +1,694 @@
+/*
+ * downmix.c
+ * Copyright (C) 2004 Gildas Bazin <gbazin@videolan.org>
+ * Copyright (C) 2000-2003 Michel Lespinasse <walken@zoy.org>
+ * Copyright (C) 1999-2000 Aaron Holtzman <aholtzma@ess.engr.uvic.ca>
+ *
+ * This file is part of libdca, a free DTS Coherent Acoustics stream decoder.
+ * See http://www.videolan.org/developers/libdca.html for updates.
+ *
+ * libdca 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.
+ *
+ * libdca 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 Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "config.h"
+
+#include <string.h>
+#include <inttypes.h>
+
+#include "dca.h"
+#include "dca_internal.h"
+
+#define CONVERT(acmod,output) (((output) << DCA_CHANNEL_BITS) + (acmod))
+
+int dca_downmix_init (int input, int flags, level_t * level,
+		      level_t clev, level_t slev)
+{
+    static uint8_t table[11][10] = {
+        /* DCA_MONO */
+        {DCA_MONO,      DCA_MONO,       DCA_MONO,       DCA_MONO,
+         DCA_MONO,      DCA_MONO,       DCA_MONO,       DCA_MONO,
+         DCA_MONO,      DCA_MONO},
+        /* DCA_CHANNEL */
+        {DCA_MONO,      DCA_CHANNEL,    DCA_STEREO,     DCA_STEREO,
+         DCA_STEREO,    DCA_STEREO,     DCA_STEREO,     DCA_STEREO,
+         DCA_STEREO,    DCA_STEREO},
+        /* DCA_STEREO */
+        {DCA_MONO,      DCA_CHANNEL,    DCA_STEREO,     DCA_STEREO,
+         DCA_STEREO,    DCA_STEREO,     DCA_STEREO,     DCA_STEREO,
+         DCA_STEREO,    DCA_STEREO},
+        /* DCA_STEREO_SUMDIFF */
+        {DCA_MONO,      DCA_CHANNEL,    DCA_STEREO,     DCA_STEREO,
+         DCA_STEREO,    DCA_STEREO,     DCA_STEREO,     DCA_STEREO,
+         DCA_STEREO,    DCA_STEREO},
+        /* DCA_STEREO_TOTAL */
+        {DCA_MONO,      DCA_CHANNEL,    DCA_STEREO,     DCA_STEREO,
+         DCA_STEREO,    DCA_STEREO,     DCA_STEREO,     DCA_STEREO,
+         DCA_STEREO,    DCA_STEREO},
+        /* DCA_3F */
+        {DCA_MONO,      DCA_CHANNEL,    DCA_STEREO,     DCA_STEREO,
+         DCA_STEREO,    DCA_3F,         DCA_3F,         DCA_3F,
+         DCA_3F,        DCA_3F},
+        /* DCA_2F1R */
+        {DCA_MONO,      DCA_CHANNEL,    DCA_STEREO,     DCA_STEREO,
+         DCA_STEREO,    DCA_2F1R,       DCA_2F1R,       DCA_2F1R,
+         DCA_2F1R,      DCA_2F1R},
+        /* DCA_3F1R */
+        {DCA_MONO,      DCA_CHANNEL,    DCA_STEREO,     DCA_STEREO,
+         DCA_STEREO,    DCA_3F,         DCA_3F1R,       DCA_3F1R,
+         DCA_3F1R,      DCA_3F1R},
+        /* DCA_2F2R */
+        {DCA_MONO,      DCA_CHANNEL,    DCA_STEREO,     DCA_STEREO,
+         DCA_STEREO,    DCA_STEREO,     DCA_2F2R,       DCA_2F2R,
+         DCA_2F2R,      DCA_2F2R},
+        /* DCA_3F2R */
+        {DCA_MONO,      DCA_CHANNEL,    DCA_STEREO,     DCA_STEREO,
+         DCA_STEREO,    DCA_3F,         DCA_3F2R,       DCA_3F2R,
+         DCA_3F2R,      DCA_3F2R},
+        /* DCA_4F2R */
+        {DCA_MONO,      DCA_CHANNEL,    DCA_STEREO,     DCA_STEREO,
+         DCA_STEREO,    DCA_4F2R,       DCA_4F2R,       DCA_4F2R,
+         DCA_4F2R,      DCA_4F2R},
+    };
+    int output;
+
+    output = flags & DCA_CHANNEL_MASK;
+
+    if (output > DCA_CHANNEL_MAX)
+	return -1;
+
+    output = table[output][input];
+
+    if (output == DCA_STEREO &&
+	(input == DCA_DOLBY || (input == DCA_3F && clev == LEVEL (LEVEL_3DB))))
+	output = DCA_DOLBY;
+
+    if (flags & DCA_ADJUST_LEVEL) {
+	level_t adjust;
+
+	switch (CONVERT (input & 7, output)) {
+
+	case CONVERT (DCA_3F, DCA_MONO):
+	    adjust = DIV (LEVEL_3DB, LEVEL (1) + clev);
+	    break;
+
+	case CONVERT (DCA_STEREO, DCA_MONO):
+	case CONVERT (DCA_2F2R, DCA_2F1R):
+	case CONVERT (DCA_3F2R, DCA_3F1R):
+	level_3db:
+	    adjust = LEVEL (LEVEL_3DB);
+	    break;
+
+	case CONVERT (DCA_3F2R, DCA_2F1R):
+	    if (clev < LEVEL (LEVEL_PLUS3DB - 1))
+		goto level_3db;
+	    /* break thru */
+	case CONVERT (DCA_3F, DCA_STEREO):
+	case CONVERT (DCA_3F1R, DCA_2F1R):
+	case CONVERT (DCA_3F1R, DCA_2F2R):
+	case CONVERT (DCA_3F2R, DCA_2F2R):
+	    adjust = DIV (1, LEVEL (1) + clev);
+	    break;
+
+	case CONVERT (DCA_2F1R, DCA_MONO):
+	    adjust = DIV (LEVEL_PLUS3DB, LEVEL (2) + slev);
+	    break;
+
+	case CONVERT (DCA_2F1R, DCA_STEREO):
+	case CONVERT (DCA_3F1R, DCA_3F):
+	    adjust = DIV (1, LEVEL (1) + MUL_C (slev, LEVEL_3DB));
+	    break;
+
+	case CONVERT (DCA_3F1R, DCA_MONO):
+	    adjust = DIV (LEVEL_3DB, LEVEL (1) + clev + MUL_C (slev, 0.5));
+	    break;
+
+	case CONVERT (DCA_3F1R, DCA_STEREO):
+	    adjust = DIV (1, LEVEL (1) + clev + MUL_C (slev, LEVEL_3DB));
+	    break;
+
+	case CONVERT (DCA_2F2R, DCA_MONO):
+	    adjust = DIV (LEVEL_3DB, LEVEL (1) + slev);
+	    break;
+
+	case CONVERT (DCA_2F2R, DCA_STEREO):
+	case CONVERT (DCA_3F2R, DCA_3F):
+	    adjust = DIV (1, LEVEL (1) + slev);
+	    break;
+
+	case CONVERT (DCA_3F2R, DCA_MONO):
+	    adjust = DIV (LEVEL_3DB, LEVEL (1) + clev + slev);
+	    break;
+
+	case CONVERT (DCA_3F2R, DCA_STEREO):
+	    adjust = DIV (1, LEVEL (1) + clev + slev);
+	    break;
+
+	case CONVERT (DCA_MONO, DCA_DOLBY):
+	    adjust = LEVEL (LEVEL_PLUS3DB);
+	    break;
+
+	case CONVERT (DCA_3F, DCA_DOLBY):
+	case CONVERT (DCA_2F1R, DCA_DOLBY):
+	    adjust = LEVEL (1 / (1 + LEVEL_3DB));
+	    break;
+
+	case CONVERT (DCA_3F1R, DCA_DOLBY):
+	case CONVERT (DCA_2F2R, DCA_DOLBY):
+	    adjust = LEVEL (1 / (1 + 2 * LEVEL_3DB));
+	    break;
+
+	case CONVERT (DCA_3F2R, DCA_DOLBY):
+	    adjust = LEVEL (1 / (1 + 3 * LEVEL_3DB));
+	    break;
+
+	default:
+	    return output;
+	}
+
+	*level = MUL_L (*level, adjust);
+    }
+
+    return output;
+}
+
+int dca_downmix_coeff (level_t * coeff, int acmod, int output, level_t level,
+		       level_t clev, level_t slev)
+{
+    level_t level_3db;
+
+    level_3db = MUL_C (level, LEVEL_3DB);
+
+    switch (CONVERT (acmod, output & DCA_CHANNEL_MASK)) {
+
+    case CONVERT (DCA_CHANNEL, DCA_CHANNEL):
+    case CONVERT (DCA_MONO, DCA_MONO):
+    case CONVERT (DCA_STEREO, DCA_STEREO):
+    case CONVERT (DCA_3F, DCA_3F):
+    case CONVERT (DCA_2F1R, DCA_2F1R):
+    case CONVERT (DCA_3F1R, DCA_3F1R):
+    case CONVERT (DCA_2F2R, DCA_2F2R):
+    case CONVERT (DCA_3F2R, DCA_3F2R):
+    case CONVERT (DCA_STEREO, DCA_DOLBY):
+	coeff[0] = coeff[1] = coeff[2] = coeff[3] = coeff[4] = level;
+	return 0;
+
+    case CONVERT (DCA_CHANNEL, DCA_MONO):
+	coeff[0] = coeff[1] = MUL_C (level, LEVEL_6DB);
+	return 3;
+
+    case CONVERT (DCA_STEREO, DCA_MONO):
+	coeff[0] = coeff[1] = level_3db;
+	return 3;
+
+    case CONVERT (DCA_3F, DCA_MONO):
+	coeff[0] = coeff[2] = level_3db;
+	coeff[1] = MUL_C (MUL_L (level_3db, clev), LEVEL_PLUS6DB);
+	return 7;
+
+    case CONVERT (DCA_2F1R, DCA_MONO):
+	coeff[0] = coeff[1] = level_3db;
+	coeff[2] = MUL_L (level_3db, slev);
+	return 7;
+
+    case CONVERT (DCA_2F2R, DCA_MONO):
+	coeff[0] = coeff[1] = level_3db;
+	coeff[2] = coeff[3] = MUL_L (level_3db, slev);
+	return 15;
+
+    case CONVERT (DCA_3F1R, DCA_MONO):
+	coeff[0] = coeff[2] = level_3db;
+	coeff[1] = MUL_C (MUL_L (level_3db, clev), LEVEL_PLUS6DB);
+	coeff[3] = MUL_L (level_3db, slev);
+	return 15;
+
+    case CONVERT (DCA_3F2R, DCA_MONO):
+	coeff[0] = coeff[2] = level_3db;
+	coeff[1] = MUL_C (MUL_L (level_3db, clev), LEVEL_PLUS6DB);
+	coeff[3] = coeff[4] = MUL_L (level_3db, slev);
+	return 31;
+
+    case CONVERT (DCA_MONO, DCA_DOLBY):
+	coeff[0] = level_3db;
+	return 0;
+
+    case CONVERT (DCA_3F, DCA_DOLBY):
+	coeff[0] = coeff[2] = coeff[3] = coeff[4] = level;
+	coeff[1] = level_3db;
+	return 7;
+
+    case CONVERT (DCA_3F, DCA_STEREO):
+    case CONVERT (DCA_3F1R, DCA_2F1R):
+    case CONVERT (DCA_3F2R, DCA_2F2R):
+	coeff[0] = coeff[2] = coeff[3] = coeff[4] = level;
+	coeff[1] = MUL_L (level, clev);
+	return 7;
+
+    case CONVERT (DCA_2F1R, DCA_DOLBY):
+	coeff[0] = coeff[1] = level;
+	coeff[2] = level_3db;
+	return 7;
+
+    case CONVERT (DCA_2F1R, DCA_STEREO):
+	coeff[0] = coeff[1] = level;
+	coeff[2] = MUL_L (level_3db, slev);
+	return 7;
+
+    case CONVERT (DCA_3F1R, DCA_DOLBY):
+	coeff[0] = coeff[2] = level;
+	coeff[1] = coeff[3] = level_3db;
+	return 15;
+
+    case CONVERT (DCA_3F1R, DCA_STEREO):
+	coeff[0] = coeff[2] = level;
+	coeff[1] = MUL_L (level, clev);
+	coeff[3] = MUL_L (level_3db, slev);
+	return 15;
+
+    case CONVERT (DCA_2F2R, DCA_DOLBY):
+	coeff[0] = coeff[1] = level;
+	coeff[2] = coeff[3] = level_3db;
+	return 15;
+
+    case CONVERT (DCA_2F2R, DCA_STEREO):
+	coeff[0] = coeff[1] = level;
+	coeff[2] = coeff[3] = MUL_L (level, slev);
+	return 15;
+
+    case CONVERT (DCA_3F2R, DCA_DOLBY):
+	coeff[0] = coeff[2] = level;
+	coeff[1] = coeff[3] = coeff[4] = level_3db;
+	return 31;
+
+    case CONVERT (DCA_3F2R, DCA_2F1R):
+	coeff[0] = coeff[2] = level;
+	coeff[1] = MUL_L (level, clev);
+	coeff[3] = coeff[4] = level_3db;
+	return 31;
+
+    case CONVERT (DCA_3F2R, DCA_STEREO):
+	coeff[0] = coeff[2] = level;
+	coeff[1] = MUL_L (level, clev);
+	coeff[3] = coeff[4] = MUL_L (level, slev);
+	return 31;
+
+    case CONVERT (DCA_3F1R, DCA_3F):
+	coeff[0] = coeff[1] = coeff[2] = level;
+	coeff[3] = MUL_L (level_3db, slev);
+	return 13;
+
+    case CONVERT (DCA_3F2R, DCA_3F):
+	coeff[0] = coeff[1] = coeff[2] = level;
+	coeff[3] = coeff[4] = MUL_L (level, slev);
+	return 29;
+
+    case CONVERT (DCA_2F2R, DCA_2F1R):
+	coeff[0] = coeff[1] = level;
+	coeff[2] = coeff[3] = level_3db;
+	return 12;
+
+    case CONVERT (DCA_3F2R, DCA_3F1R):
+	coeff[0] = coeff[1] = coeff[2] = level;
+	coeff[3] = coeff[4] = level_3db;
+	return 24;
+
+    case CONVERT (DCA_2F1R, DCA_2F2R):
+	coeff[0] = coeff[1] = level;
+	coeff[2] = level_3db;
+	return 0;
+
+    case CONVERT (DCA_3F1R, DCA_2F2R):
+	coeff[0] = coeff[2] = level;
+	coeff[1] = MUL_L (level, clev);
+	coeff[3] = level_3db;
+	return 7;
+
+    case CONVERT (DCA_3F1R, DCA_3F2R):
+	coeff[0] = coeff[1] = coeff[2] = level;
+	coeff[3] = level_3db;
+	return 0;
+    }
+
+    return -1;	/* NOTREACHED */
+}
+
+static void mix2to1 (sample_t * dest, sample_t * src, sample_t bias)
+{
+    int i;
+
+    for (i = 0; i < 256; i++)
+	dest[i] += BIAS (src[i]);
+}
+
+static void mix3to1 (sample_t * samples, sample_t bias)
+{
+    int i;
+
+    for (i = 0; i < 256; i++)
+	samples[i] += BIAS (samples[i + 256] + samples[i + 512]);
+}
+
+static void mix4to1 (sample_t * samples, sample_t bias)
+{
+    int i;
+
+    for (i = 0; i < 256; i++)
+	samples[i] += BIAS (samples[i + 256] + samples[i + 512] +
+			    samples[i + 768]);
+}
+
+static void mix5to1 (sample_t * samples, sample_t bias)
+{
+    int i;
+
+    for (i = 0; i < 256; i++)
+	samples[i] += BIAS (samples[i + 256] + samples[i + 512] +
+			    samples[i + 768] + samples[i + 1024]);
+}
+
+static void mix3to2 (sample_t * samples, sample_t bias)
+{
+    int i;
+    sample_t common;
+
+    for (i = 0; i < 256; i++) {
+	common = BIAS (samples[i]);
+	samples[i] = samples[i + 256] + common;
+	samples[i + 256] = samples[i + 512] + common;
+    }
+}
+
+static void mix21to2 (sample_t * left, sample_t * right, sample_t bias)
+{
+    int i;
+    sample_t common;
+
+    for (i = 0; i < 256; i++) {
+	common = BIAS (right[i + 256]);
+	left[i] += common;
+	right[i] += common;
+    }
+}
+
+static void mix21toS (sample_t * samples, sample_t bias)
+{
+    int i;
+    sample_t surround;
+
+    for (i = 0; i < 256; i++) {
+	surround = samples[i + 512];
+	samples[i] += BIAS (-surround);
+	samples[i + 256] += BIAS (surround);
+    }
+}
+
+static void mix31to2 (sample_t * samples, sample_t bias)
+{
+    int i;
+    sample_t common;
+
+    for (i = 0; i < 256; i++) {
+	common = BIAS (samples[i] + samples[i + 768]);
+	samples[i] = samples[i + 256] + common;
+	samples[i + 256] = samples[i + 512] + common;
+    }
+}
+
+static void mix31toS (sample_t * samples, sample_t bias)
+{
+    int i;
+    sample_t common, surround;
+
+    for (i = 0; i < 256; i++) {
+	common = BIAS (samples[i]);
+	surround = samples[i + 768];
+	samples[i] = samples[i + 256] + common - surround;
+	samples[i + 256] = samples[i + 512] + common + surround;
+    }
+}
+
+static void mix22toS (sample_t * samples, sample_t bias)
+{
+    int i;
+    sample_t surround;
+
+    for (i = 0; i < 256; i++) {
+	surround = samples[i + 512] + samples[i + 768];
+	samples[i] += BIAS (-surround);
+	samples[i + 256] += BIAS (surround);
+    }
+}
+
+static void mix32to2 (sample_t * samples, sample_t bias)
+{
+    int i;
+    sample_t common;
+
+    for (i = 0; i < 256; i++) {
+	common = BIAS (samples[i]);
+	samples[i] = common + samples[i + 256] + samples[i + 768];
+	samples[i + 256] = common + samples[i + 512] + samples[i + 1024];
+    }
+}
+
+static void mix32toS (sample_t * samples, sample_t bias)
+{
+    int i;
+    sample_t common, surround;
+
+    for (i = 0; i < 256; i++) {
+	common = BIAS (samples[i]);
+	surround = samples[i + 768] + samples[i + 1024];
+	samples[i] = samples[i + 256] + common - surround;
+	samples[i + 256] = samples[i + 512] + common + surround;
+    }
+}
+
+static void move2to1 (sample_t * src, sample_t * dest, sample_t bias)
+{
+    int i;
+
+    for (i = 0; i < 256; i++)
+	dest[i] = BIAS (src[i] + src[i + 256]);
+}
+
+static void zero (sample_t * samples)
+{
+    int i;
+
+    for (i = 0; i < 256; i++)
+	samples[i] = 0;
+}
+
+void dca_downmix (sample_t * samples, int acmod, int output, sample_t bias,
+		  level_t clev, level_t slev)
+{
+    (void)clev;
+
+    switch (CONVERT (acmod, output & DCA_CHANNEL_MASK)) {
+
+    case CONVERT (DCA_CHANNEL, DCA_MONO):
+    case CONVERT (DCA_STEREO, DCA_MONO):
+    mix_2to1:
+	mix2to1 (samples, samples + 256, bias);
+	break;
+
+    case CONVERT (DCA_2F1R, DCA_MONO):
+	if (slev == 0)
+	    goto mix_2to1;
+    case CONVERT (DCA_3F, DCA_MONO):
+    mix_3to1:
+	mix3to1 (samples, bias);
+	break;
+
+    case CONVERT (DCA_3F1R, DCA_MONO):
+	if (slev == 0)
+	    goto mix_3to1;
+    case CONVERT (DCA_2F2R, DCA_MONO):
+	if (slev == 0)
+	    goto mix_2to1;
+	mix4to1 (samples, bias);
+	break;
+
+    case CONVERT (DCA_3F2R, DCA_MONO):
+	if (slev == 0)
+	    goto mix_3to1;
+	mix5to1 (samples, bias);
+	break;
+
+    case CONVERT (DCA_MONO, DCA_DOLBY):
+	memcpy (samples + 256, samples, 256 * sizeof (sample_t));
+	break;
+
+    case CONVERT (DCA_3F, DCA_STEREO):
+    case CONVERT (DCA_3F, DCA_DOLBY):
+    mix_3to2:
+	mix3to2 (samples, bias);
+	break;
+
+    case CONVERT (DCA_2F1R, DCA_STEREO):
+	if (slev == 0)
+	    break;
+	mix21to2 (samples, samples + 256, bias);
+	break;
+
+    case CONVERT (DCA_2F1R, DCA_DOLBY):
+	mix21toS (samples, bias);
+	break;
+
+    case CONVERT (DCA_3F1R, DCA_STEREO):
+	if (slev == 0)
+	    goto mix_3to2;
+	mix31to2 (samples, bias);
+	break;
+
+    case CONVERT (DCA_3F1R, DCA_DOLBY):
+	mix31toS (samples, bias);
+	break;
+
+    case CONVERT (DCA_2F2R, DCA_STEREO):
+	if (slev == 0)
+	    break;
+	mix2to1 (samples, samples + 512, bias);
+	mix2to1 (samples + 256, samples + 768, bias);
+	break;
+
+    case CONVERT (DCA_2F2R, DCA_DOLBY):
+	mix22toS (samples, bias);
+	break;
+
+    case CONVERT (DCA_3F2R, DCA_STEREO):
+	if (slev == 0)
+	    goto mix_3to2;
+	mix32to2 (samples, bias);
+	break;
+
+    case CONVERT (DCA_3F2R, DCA_DOLBY):
+	mix32toS (samples, bias);
+	break;
+
+    case CONVERT (DCA_3F1R, DCA_3F):
+	if (slev == 0)
+	    break;
+	mix21to2 (samples, samples + 512, bias);
+	break;
+
+    case CONVERT (DCA_3F2R, DCA_3F):
+	if (slev == 0)
+	    break;
+	mix2to1 (samples, samples + 768, bias);
+	mix2to1 (samples + 512, samples + 1024, bias);
+	break;
+
+    case CONVERT (DCA_3F1R, DCA_2F1R):
+	mix3to2 (samples, bias);
+	memcpy (samples + 512, samples + 768, 256 * sizeof (sample_t));
+	break;
+
+    case CONVERT (DCA_2F2R, DCA_2F1R):
+	mix2to1 (samples + 512, samples + 768, bias);
+	break;
+
+    case CONVERT (DCA_3F2R, DCA_2F1R):
+	mix3to2 (samples, bias);
+	move2to1 (samples + 768, samples + 512, bias);
+	break;
+
+    case CONVERT (DCA_3F2R, DCA_3F1R):
+	mix2to1 (samples + 768, samples + 1024, bias);
+	break;
+
+    case CONVERT (DCA_2F1R, DCA_2F2R):
+	memcpy (samples + 768, samples + 512, 256 * sizeof (sample_t));
+	break;
+
+    case CONVERT (DCA_3F1R, DCA_2F2R):
+	mix3to2 (samples, bias);
+	memcpy (samples + 512, samples + 768, 256 * sizeof (sample_t));
+	break;
+
+    case CONVERT (DCA_3F2R, DCA_2F2R):
+	mix3to2 (samples, bias);
+	memcpy (samples + 512, samples + 768, 256 * sizeof (sample_t));
+	memcpy (samples + 768, samples + 1024, 256 * sizeof (sample_t));
+	break;
+
+    case CONVERT (DCA_3F1R, DCA_3F2R):
+	memcpy (samples + 1024, samples + 768, 256 * sizeof (sample_t));
+	break;
+    }
+}
+
+void dca_upmix (sample_t * samples, int acmod, int output)
+{
+    switch (CONVERT (acmod, output & DCA_CHANNEL_MASK)) {
+
+    case CONVERT (DCA_3F2R, DCA_MONO):
+	zero (samples + 1024);
+    case CONVERT (DCA_3F1R, DCA_MONO):
+    case CONVERT (DCA_2F2R, DCA_MONO):
+	zero (samples + 768);
+    case CONVERT (DCA_3F, DCA_MONO):
+    case CONVERT (DCA_2F1R, DCA_MONO):
+	zero (samples + 512);
+    case CONVERT (DCA_CHANNEL, DCA_MONO):
+    case CONVERT (DCA_STEREO, DCA_MONO):
+	zero (samples + 256);
+	break;
+
+    case CONVERT (DCA_3F2R, DCA_STEREO):
+    case CONVERT (DCA_3F2R, DCA_DOLBY):
+	zero (samples + 1024);
+    case CONVERT (DCA_3F1R, DCA_STEREO):
+    case CONVERT (DCA_3F1R, DCA_DOLBY):
+	zero (samples + 768);
+    case CONVERT (DCA_3F, DCA_STEREO):
+    case CONVERT (DCA_3F, DCA_DOLBY):
+    mix_3to2:
+	memcpy (samples + 512, samples + 256, 256 * sizeof (sample_t));
+	zero (samples + 256);
+	break;
+
+    case CONVERT (DCA_2F2R, DCA_STEREO):
+    case CONVERT (DCA_2F2R, DCA_DOLBY):
+	zero (samples + 768);
+    case CONVERT (DCA_2F1R, DCA_STEREO):
+    case CONVERT (DCA_2F1R, DCA_DOLBY):
+	zero (samples + 512);
+	break;
+
+    case CONVERT (DCA_3F2R, DCA_3F):
+	zero (samples + 1024);
+    case CONVERT (DCA_3F1R, DCA_3F):
+    case CONVERT (DCA_2F2R, DCA_2F1R):
+	zero (samples + 768);
+	break;
+
+    case CONVERT (DCA_3F2R, DCA_3F1R):
+	zero (samples + 1024);
+	break;
+
+    case CONVERT (DCA_3F2R, DCA_2F1R):
+	zero (samples + 1024);
+    case CONVERT (DCA_3F1R, DCA_2F1R):
+    mix_31to21:
+	memcpy (samples + 768, samples + 512, 256 * sizeof (sample_t));
+	goto mix_3to2;
+
+    case CONVERT (DCA_3F2R, DCA_2F2R):
+	memcpy (samples + 1024, samples + 768, 256 * sizeof (sample_t));
+	goto mix_31to21;
+    }
+}