2 * copyright (c) 2001 Fabrice Bellard
4 * This library is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Lesser General Public
6 * License as published by the Free Software Foundation; either
7 * version 2 of the License, or (at your option) any later version.
9 * This library is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * Lesser General Public License for more details.
14 * You should have received a copy of the GNU Lesser General Public
15 * License along with this library; if not, write to the Free Software
16 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21 * mpeg audio declarations for both encoder and decoder.
24 /* max frame size, in samples */
25 #define MPA_FRAME_SIZE 1152
27 /* max compressed frame size */
28 #define MPA_MAX_CODED_FRAME_SIZE 1792
30 #define MPA_MAX_CHANNELS 2
32 #define SBLIMIT 32 /* number of subbands */
39 /* header + layer + bitrate + freq + lsf/mpeg25 */
40 #define SAME_HEADER_MASK \
41 (0xffe00000 | (3 << 17) | (0xf << 12) | (3 << 10) | (3 << 19))
43 /* define USE_HIGHPRECISION to have a bit exact (but slower) mpeg
46 #ifdef USE_HIGHPRECISION
47 #define FRAC_BITS 23 /* fractional bits for sb_samples and dct */
48 #define WFRAC_BITS 16 /* fractional bits for window */
50 #define FRAC_BITS 15 /* fractional bits for sb_samples and dct */
51 #define WFRAC_BITS 14 /* fractional bits for window */
54 #if defined(USE_HIGHPRECISION) && defined(CONFIG_AUDIO_NONSHORT)
55 typedef int32_t OUT_INT;
56 #define OUT_MAX INT32_MAX
57 #define OUT_MIN INT32_MIN
58 #define OUT_SHIFT (WFRAC_BITS + FRAC_BITS - 31)
60 typedef int16_t OUT_INT;
61 #define OUT_MAX INT16_MAX
62 #define OUT_MIN INT16_MIN
63 #define OUT_SHIFT (WFRAC_BITS + FRAC_BITS - 15)
67 typedef int16_t MPA_INT;
69 typedef int32_t MPA_INT;
72 int l2_select_table(int bitrate, int nb_channels, int freq, int lsf);
73 int mpa_decode_header(AVCodecContext *avctx, uint32_t head);
74 void ff_mpa_synth_init(MPA_INT *window);
75 void ff_mpa_synth_filter(MPA_INT *synth_buf_ptr, int *synth_buf_offset,
76 MPA_INT *window, int *dither_state,
77 OUT_INT *samples, int incr,
78 int32_t sb_samples[SBLIMIT]);
80 extern const uint16_t mpa_bitrate_tab[2][3][15];
81 extern const uint16_t mpa_freq_tab[3];
82 extern const unsigned char *alloc_tables[5];
83 extern const double enwindow[512];
84 extern const int sblimit_table[5];
85 extern const int quant_steps[17];
86 extern const int quant_bits[17];
87 extern const int32_t mpa_enwindow[257];
89 /* fast header check for resync */
90 static inline int ff_mpa_check_header(uint32_t header){
92 if ((header & 0xffe00000) != 0xffe00000)
95 if ((header & (3<<17)) == 0)
98 if ((header & (0xf<<12)) == 0xf<<12)
101 if ((header & (3<<10)) == 3<<10)