header for common code between mp3 decoder and encoder.

unfinished, iam just commiting this so the functions that should be
non static have prototypes.


git-svn-id: file:///var/local/repositories/ffmpeg/trunk@22270 9553f0bf-9b14-0410-a0b8-cfaf0461ba5b

libavcodec/mpegaudio3.h

+/*
+ * Copyright (c) 2007 Michael Niedermayer
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg 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 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg 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 FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+/* layer 3 "granule" */
+typedef struct GranuleDef {
+    uint8_t scfsi;
+    int part2_3_length;
+    int big_values;
+    int global_gain;
+    int scalefac_compress;
+    uint8_t block_type;
+    uint8_t switch_point;
+    int table_select[3];
+    int subblock_gain[3];
+    uint8_t scalefac_scale;
+    uint8_t count1table_select;
+    int region_size[3]; /* number of huffman codes in each region */
+    int preflag;
+    int short_start, long_end; /* long/short band indexes */
+    uint8_t scale_factors[40];
+    int32_t sb_hybrid[SBLIMIT * 18]; /* 576 samples */
+} GranuleDef;
+
+void ff_mp3_init(void);
+
+/**
+ * Compute huffman coded region sizes.
+ */
+void ff_init_short_region(MPADecodeContext *s, GranuleDef *g);
+
+/**
+ * Compute huffman coded region sizes.
+ */
+void ff_init_long_region(MPADecodeContext *s, GranuleDef *g, int ra1, int ra2);
+
+void ff_compute_band_indexes(MPADecodeContext *s, GranuleDef *g);