Initial revision

Originally committed as revision 5 to svn://svn.ffmpeg.org/ffmpeg/trunk

1 files changed, 255 insertions, 0 deletions

diff --git a/libavcodec/libac3/bit_allocate.c b/libavcodec/libac3/bit_allocate.c
new file mode 100644
index 0000000000..307c0074c6
--- /dev/null
+++ b/libavcodec/libac3/bit_allocate.c
@@ -0,0 +1,255 @@
+/* 
+ *  bit_allocate.c
+ *
+ *	Copyright (C) Aaron Holtzman - May 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. 
+ *
+ */
+
+#include <inttypes.h>
+#include <stdlib.h>
+#include <string.h>
+#include "ac3.h"
+#include "ac3_internal.h"
+
+static int hthtab[3][50] = {
+    {0x730, 0x730, 0x7c0, 0x800, 0x820, 0x840, 0x850, 0x850, 0x860, 0x860,
+     0x860, 0x860, 0x860, 0x870, 0x870, 0x870, 0x880, 0x880, 0x890, 0x890,
+     0x8a0, 0x8a0, 0x8b0, 0x8b0, 0x8c0, 0x8c0, 0x8d0, 0x8e0, 0x8f0, 0x900,
+     0x910, 0x910, 0x910, 0x910, 0x900, 0x8f0, 0x8c0, 0x870, 0x820, 0x7e0,
+     0x7a0, 0x770, 0x760, 0x7a0, 0x7c0, 0x7c0, 0x6e0, 0x400, 0x3c0, 0x3c0},
+    {0x710, 0x710, 0x7a0, 0x7f0, 0x820, 0x830, 0x840, 0x850, 0x850, 0x860,
+     0x860, 0x860, 0x860, 0x860, 0x870, 0x870, 0x870, 0x880, 0x880, 0x880,
+     0x890, 0x890, 0x8a0, 0x8a0, 0x8b0, 0x8b0, 0x8c0, 0x8c0, 0x8e0, 0x8f0,
+     0x900, 0x910, 0x910, 0x910, 0x910, 0x900, 0x8e0, 0x8b0, 0x870, 0x820,
+     0x7e0, 0x7b0, 0x760, 0x770, 0x7a0, 0x7c0, 0x780, 0x5d0, 0x3c0, 0x3c0},
+    {0x680, 0x680, 0x750, 0x7b0, 0x7e0, 0x810, 0x820, 0x830, 0x840, 0x850,
+     0x850, 0x850, 0x860, 0x860, 0x860, 0x860, 0x860, 0x860, 0x860, 0x860,
+     0x870, 0x870, 0x870, 0x870, 0x880, 0x880, 0x880, 0x890, 0x8a0, 0x8b0,
+     0x8c0, 0x8d0, 0x8e0, 0x8f0, 0x900, 0x910, 0x910, 0x910, 0x900, 0x8f0,
+     0x8d0, 0x8b0, 0x840, 0x7f0, 0x790, 0x760, 0x7a0, 0x7c0, 0x7b0, 0x720}
+};
+
+static int8_t baptab[305] = {
+    16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16,
+    16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16,
+    16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16,
+    16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16,
+    16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16,
+    16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16,	// 93 padding entries
+
+    16, 16, 16, 16, 16, 16, 16, 16, 16, 14, 14, 14, 14, 14, 14, 14,
+    14, 12, 12, 12, 12, 11, 11, 11, 11, 10, 10, 10, 10,  9,  9,  9,
+     9,  8,  8,  8,  8,  7,  7,  7,  7,  6,  6,  6,  6,  5,  5,  5,
+     5,  4,  4, -3, -3,  3,  3,  3, -2, -2, -1, -1, -1, -1, -1,  0,
+
+     0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,
+     0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,
+     0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,
+     0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,
+     0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,
+     0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,
+     0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,
+     0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,
+     0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,
+     0,  0,  0,  0					// 148 padding entries
+};
+
+static int bndtab[30] = {21, 22,  23,  24,  25,  26,  27,  28,  31,  34,
+			 37, 40,  43,  46,  49,  55,  61,  67,  73,  79,
+			 85, 97, 109, 121, 133, 157, 181, 205, 229, 253};
+
+static int8_t latab[256] = {
+    -64, -63, -62, -61, -60, -59, -58, -57, -56, -55, -54, -53,
+    -52, -52, -51, -50, -49, -48, -47, -47, -46, -45, -44, -44,
+    -43, -42, -41, -41, -40, -39, -38, -38, -37, -36, -36, -35,
+    -35, -34, -33, -33, -32, -32, -31, -30, -30, -29, -29, -28,
+    -28, -27, -27, -26, -26, -25, -25, -24, -24, -23, -23, -22,
+    -22, -21, -21, -21, -20, -20, -19, -19, -19, -18, -18, -18,
+    -17, -17, -17, -16, -16, -16, -15, -15, -15, -14, -14, -14,
+    -13, -13, -13, -13, -12, -12, -12, -12, -11, -11, -11, -11,
+    -10, -10, -10, -10, -10,  -9,  -9,  -9,  -9,  -9,  -8,  -8,
+     -8,  -8,  -8,  -8,  -7,  -7,  -7,  -7,  -7,  -7,  -6,  -6,
+     -6,  -6,  -6,  -6,  -6,  -6,  -5,  -5,  -5,  -5,  -5,  -5,
+     -5,  -5,  -4,  -4,  -4,  -4,  -4,  -4,  -4,  -4,  -4,  -4,
+     -4,  -3,  -3,  -3,  -3,  -3,  -3,  -3,  -3,  -3,  -3,  -3,
+     -3,  -3,  -3,  -2,  -2,  -2,  -2,  -2,  -2,  -2,  -2,  -2,
+     -2,  -2,  -2,  -2,  -2,  -2,  -2,  -2,  -2,  -2,  -1,  -1,
+     -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,
+     -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,  -1,
+     -1,  -1,  -1,  -1,  -1,  -1,   0,   0,   0,   0,   0,   0,
+      0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+      0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+      0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+      0,   0,   0,   0
+};
+
+#define UPDATE_LEAK() 		\
+do {				\
+    fastleak += fdecay;		\
+    if (fastleak > psd + fgain)	\
+	fastleak = psd + fgain;	\
+    slowleak += sdecay;		\
+    if (slowleak > psd + sgain)	\
+	slowleak = psd + sgain;	\
+} while (0)
+
+#define COMPUTE_MASK()				\
+do {						\
+    if (psd > dbknee)				\
+	mask -= (psd - dbknee) >> 2;		\
+    if (mask > hth [i >> halfrate])		\
+	mask = hth [i >> halfrate];		\
+    mask -= snroffset + 128 * deltba[i];	\
+    mask = (mask > 0) ? 0 : ((-mask) >> 5);	\
+    mask -= floor;				\
+} while (0)
+
+void bit_allocate (ac3_state_t * state, ac3_ba_t * ba, int bndstart,
+		   int start, int end, int fastleak, int slowleak,
+		   uint8_t * exp, int8_t * bap)
+{
+    static int slowgain[4] = {0x540, 0x4d8, 0x478, 0x410};
+    static int dbpbtab[4]  = {0xc00, 0x500, 0x300, 0x100};
+    static int floortab[8] = {0x910, 0x950, 0x990, 0x9d0,
+			      0xa10, 0xa90, 0xb10, 0x1400};
+
+    int i, j;
+    int fdecay, fgain, sdecay, sgain, dbknee, floor, snroffset;
+    int psd, mask;
+    int8_t * deltba;
+    int * hth;
+    int halfrate;
+
+    halfrate = state->halfrate;
+    fdecay = (63 + 20 * state->fdcycod) >> halfrate;
+    fgain = 128 + 128 * ba->fgaincod;
+    sdecay = (15 + 2 * state->sdcycod) >> halfrate;
+    sgain = slowgain[state->sgaincod];
+    dbknee = dbpbtab[state->dbpbcod];
+    hth = hthtab[state->fscod];
+    /*
+     * if there is no delta bit allocation, make deltba point to an area
+     * known to contain zeroes. baptab+156 here.
+     */
+    deltba = (ba->deltbae == DELTA_BIT_NONE) ? baptab + 156 : ba->deltba;
+    floor = floortab[state->floorcod];
+    snroffset = 960 - 64 * state->csnroffst - 4 * ba->fsnroffst + floor;
+    floor >>= 5;
+
+    i = bndstart;
+    j = start;
+    if (start == 0) {	// not the coupling channel
+	int lowcomp;
+
+	lowcomp = 0;
+	j = end - 1;
+	do {
+	    if (i < j) {
+		if (exp[i+1] == exp[i] - 2)
+		    lowcomp = 384;
+		else if (lowcomp && (exp[i+1] > exp[i]))
+		    lowcomp -= 64;
+	    }
+	    psd = 128 * exp[i];
+	    mask = psd + fgain + lowcomp;
+	    COMPUTE_MASK ();
+	    bap[i++] = (baptab+156)[mask + 4 * exp[i]];
+	} while ((i < 3) || ((i < 7) && (exp[i] > exp[i-1])));
+	fastleak = psd + fgain;
+	slowleak = psd + sgain;
+
+	while (i < 7) {
+	    if (i < j) {
+		if (exp[i+1] == exp[i] - 2)
+		    lowcomp = 384;
+		else if (lowcomp && (exp[i+1] > exp[i]))
+		    lowcomp -= 64;
+	    }
+	    psd = 128 * exp[i];
+	    UPDATE_LEAK ();
+	    mask = ((fastleak + lowcomp < slowleak) ?
+		    fastleak + lowcomp : slowleak);
+	    COMPUTE_MASK ();
+	    bap[i++] = (baptab+156)[mask + 4 * exp[i]];
+	}
+
+	if (end == 7)	// lfe channel
+	    return;
+
+	do {
+	    if (exp[i+1] == exp[i] - 2)
+		lowcomp = 320;
+	    else if (lowcomp && (exp[i+1] > exp[i]))
+		lowcomp -= 64;
+	    psd = 128 * exp[i];
+	    UPDATE_LEAK ();
+	    mask = ((fastleak + lowcomp < slowleak) ?
+		    fastleak + lowcomp : slowleak);
+	    COMPUTE_MASK ();
+	    bap[i++] = (baptab+156)[mask + 4 * exp[i]];
+	} while (i < 20);
+
+	while (lowcomp > 128) {		// two iterations maximum
+	    lowcomp -= 128;
+	    psd = 128 * exp[i];
+	    UPDATE_LEAK ();
+	    mask = ((fastleak + lowcomp < slowleak) ?
+		    fastleak + lowcomp : slowleak);
+	    COMPUTE_MASK ();
+	    bap[i++] = (baptab+156)[mask + 4 * exp[i]];
+	}
+	j = i;
+    }
+
+    do {
+	int startband, endband;
+
+	startband = j;
+	endband = ((bndtab-20)[i] < end) ? (bndtab-20)[i] : end;
+	psd = 128 * exp[j++];
+	while (j < endband) {
+	    int next, delta;
+
+	    next = 128 * exp[j++];
+	    delta = next - psd;
+	    switch (delta >> 9) {
+	    case -6: case -5: case -4: case -3: case -2:
+		psd = next;
+		break;
+	    case -1:
+		psd = next + latab[(-delta) >> 1];
+		break;
+	    case 0:
+		psd += latab[delta >> 1];
+		break;
+	    }
+	}
+	// minpsd = -289
+	UPDATE_LEAK ();
+	mask = (fastleak < slowleak) ? fastleak : slowleak;
+	COMPUTE_MASK ();
+	i++;
+	j = startband;
+	do {
+	    // max(mask+4*exp)=147=-(minpsd+fgain-deltba-snroffset)>>5+4*exp
+	    // min(mask+4*exp)=-156=-(sgain-deltba-snroffset)>>5
+	    bap[j++] = (baptab+156)[mask + 4 * exp[j]];
+	} while (j < endband);
+    } while (j < end);
+}