preparing integration of new AC3 decoder

Originally committed as revision 1089 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/ac3.h

+/*
+ * Common code between AC3 encoder and decoder
+ * Copyright (c) 2000, 2001, 2002 Fabrice Bellard.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#define AC3_MAX_CODED_FRAME_SIZE 3840 /* in bytes */
+#define AC3_MAX_CHANNELS 6 /* including LFE channel */
+
+#define NB_BLOCKS 6 /* number of PCM blocks inside an AC3 frame */
+#define AC3_FRAME_SIZE (NB_BLOCKS * 256)
+
+/* exponent encoding strategy */
+#define EXP_REUSE 0
+#define EXP_NEW   1
+
+#define EXP_D15   1
+#define EXP_D25   2
+#define EXP_D45   3
+
+typedef struct AC3BitAllocParameters {
+    int fscod; /* frequency */
+    int halfratecod;
+    int sgain, sdecay, fdecay, dbknee, floor;
+    int cplfleak, cplsleak;
+} AC3BitAllocParameters;
+
+extern const UINT16 ac3_freqs[3];
+extern const UINT16 ac3_bitratetab[19];
+extern const INT16 ac3_window[256];
+extern const UINT8 sdecaytab[4];
+extern const UINT8 fdecaytab[4];
+extern const UINT16 sgaintab[4];
+extern const UINT16 dbkneetab[4];
+extern const UINT16 floortab[8];
+extern const UINT16 fgaintab[8];
+
+void ac3_common_init(void);
+void ac3_parametric_bit_allocation(AC3BitAllocParameters *s, UINT8 *bap,
+                                   INT8 *exp, int start, int end,
+                                   int snroffset, int fgain, int is_lfe,
+                                   int deltbae,int deltnseg, 
+                                   UINT8 *deltoffst, UINT8 *deltlen, UINT8 *deltba);

libavcodec/ac3enc.h

-
-#define AC3_FRAME_SIZE (6*256)
-#define AC3_MAX_CODED_FRAME_SIZE 3840 /* in bytes */
-#define AC3_MAX_CHANNELS 6
-
-typedef struct AC3EncodeContext {
-    PutBitContext pb;
-    int nb_channels;
-    int nb_all_channels;
-    int lfe_channel;
-    int bit_rate;
-    int sample_rate;
-    int bsid;
-    int frame_size_min; /* minimum frame size in case rounding is necessary */
-    int frame_size; /* current frame size in words */
-    int halfratecod;
-    int frmsizecod;
-    int fscod; /* frequency */
-    int acmod;
-    int lfe;
-    int bsmod;
-    short last_samples[AC3_MAX_CHANNELS][256];
-    int chbwcod[AC3_MAX_CHANNELS];
-    int nb_coefs[AC3_MAX_CHANNELS];
-    
-    /* bitrate allocation control */
-    int sgaincod, sdecaycod, fdecaycod, dbkneecod, floorcod; 
-    int sgain, sdecay, fdecay, dbknee, floor;
-    int csnroffst;
-    int fgaincod[AC3_MAX_CHANNELS];
-    int fsnroffst[AC3_MAX_CHANNELS];
-    /* mantissa encoding */
-    int mant1_cnt, mant2_cnt, mant4_cnt;
-} AC3EncodeContext;

libavcodec/ac3tab.h

 /* tables taken directly from AC3 spec */
 
+/* possible frequencies */
+const UINT16 ac3_freqs[3] = { 48000, 44100, 32000 };
+
 /* possible bitrates */
-static const UINT16 bitratetab[19] = {
+const UINT16 ac3_bitratetab[19] = {
     32, 40, 48, 56, 64, 80, 96, 112, 128, 
     160, 192, 224, 256, 320, 384, 448, 512, 576, 640 
 };
@@ -9,7 +12,7 @@ static const UINT16 bitratetab[19] = {
 /* AC3 MDCT window */
 
 /* MDCT window */
-static const INT16 ac3_window[256]= {
+const INT16 ac3_window[256] = {
     4,    7,   12,   16,   21,   28,   34,   42,
    51,   61,   72,   84,   97,  111,  127,  145,
   164,  184,  207,  231,  257,  285,  315,  347,
@@ -138,27 +141,27 @@ static const UINT8 baptab[64]= {
     15, 15, 15, 15,
 };
 
-static const UINT8 sdecaytab[4]={ 
+const UINT8 sdecaytab[4]={ 
     0x0f, 0x11, 0x13, 0x15,
 };
 
-static const UINT8 fdecaytab[4]={ 
+const UINT8 fdecaytab[4]={ 
     0x3f, 0x53, 0x67, 0x7b, 
 };
 
-static const UINT16 sgaintab[4]= { 
+const UINT16 sgaintab[4]= { 
     0x540, 0x4d8, 0x478, 0x410,
 };
 
-static const UINT16 dbkneetab[4]= { 
+const UINT16 dbkneetab[4]= { 
     0x000, 0x700, 0x900, 0xb00,
 };
 
-static const UINT16 floortab[8]= { 
+const UINT16 floortab[8]= { 
     0x2f0, 0x2b0, 0x270, 0x230, 0x1f0, 0x170, 0x0f0, 0xf800,
 };
 
-static const UINT16 fgaintab[8]= {
+const UINT16 fgaintab[8]= {
     0x080, 0x100, 0x180, 0x200, 0x280, 0x300, 0x380, 0x400,
 };