2 * copyright (c) 2001 Fabrice Bellard
4 * This file is part of FFmpeg.
6 * FFmpeg is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
11 * FFmpeg is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with FFmpeg; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
23 * mpeg audio declarations for both encoder and decoder.
26 #ifndef AVCODEC_MPEGAUDIO_H
27 #define AVCODEC_MPEGAUDIO_H
30 #include "bitstream.h"
33 /* max frame size, in samples */
34 #define MPA_FRAME_SIZE 1152
36 /* max compressed frame size */
37 #define MPA_MAX_CODED_FRAME_SIZE 1792
39 #define MPA_MAX_CHANNELS 2
41 #define SBLIMIT 32 /* number of subbands */
48 /* header + layer + bitrate + freq + lsf/mpeg25 */
49 #define SAME_HEADER_MASK \
50 (0xffe00000 | (3 << 17) | (0xf << 12) | (3 << 10) | (3 << 19))
52 #define MP3_MASK 0xFFFE0CCF
54 #if CONFIG_MPEGAUDIO_HP
55 #define FRAC_BITS 23 /* fractional bits for sb_samples and dct */
56 #define WFRAC_BITS 16 /* fractional bits for window */
58 #define FRAC_BITS 15 /* fractional bits for sb_samples and dct */
59 #define WFRAC_BITS 14 /* fractional bits for window */
62 #define FRAC_ONE (1 << FRAC_BITS)
64 #define FIX(a) ((int)((a) * FRAC_ONE))
66 #if CONFIG_MPEGAUDIO_HP && CONFIG_AUDIO_NONSHORT
67 typedef int32_t OUT_INT;
68 #define OUT_MAX INT32_MAX
69 #define OUT_MIN INT32_MIN
70 #define OUT_SHIFT (WFRAC_BITS + FRAC_BITS - 31)
71 #define OUT_FMT SAMPLE_FMT_S32
73 typedef int16_t OUT_INT;
74 #define OUT_MAX INT16_MAX
75 #define OUT_MIN INT16_MIN
76 #define OUT_SHIFT (WFRAC_BITS + FRAC_BITS - 15)
77 #define OUT_FMT SAMPLE_FMT_S16
81 typedef int16_t MPA_INT;
83 typedef int32_t MPA_INT;
86 #define BACKSTEP_SIZE 512
91 typedef struct MPADecodeContext {
92 DECLARE_ALIGNED_8(uint8_t, last_buf[2*BACKSTEP_SIZE + EXTRABYTES]);
95 /* next header (used in free format parsing) */
96 uint32_t free_format_next_header;
100 int sample_rate_index; /* between 0 and 8 */
108 DECLARE_ALIGNED_16(MPA_INT, synth_buf[MPA_MAX_CHANNELS][512 * 2]);
109 int synth_buf_offset[MPA_MAX_CHANNELS];
110 DECLARE_ALIGNED_16(int32_t, sb_samples[MPA_MAX_CHANNELS][36][SBLIMIT]);
111 int32_t mdct_buf[MPA_MAX_CHANNELS][SBLIMIT * 18]; /* previous samples, for layer 3 MDCT */
115 void (*compute_antialias)(struct MPADecodeContext *s, struct GranuleDef *g);
116 int adu_mode; ///< 0 for standard mp3, 1 for adu formatted mp3
118 int error_recognition;
119 AVCodecContext* avctx;
122 /* layer 3 huffman tables */
123 typedef struct HuffTable {
126 const uint16_t *codes;
129 int ff_mpa_l2_select_table(int bitrate, int nb_channels, int freq, int lsf);
130 int ff_mpa_decode_header(AVCodecContext *avctx, uint32_t head, int *sample_rate, int *channels, int *frame_size, int *bitrate);
131 void ff_mpa_synth_init(MPA_INT *window);
132 void ff_mpa_synth_filter(MPA_INT *synth_buf_ptr, int *synth_buf_offset,
133 MPA_INT *window, int *dither_state,
134 OUT_INT *samples, int incr,
135 int32_t sb_samples[SBLIMIT]);
137 /* fast header check for resync */
138 static inline int ff_mpa_check_header(uint32_t header){
140 if ((header & 0xffe00000) != 0xffe00000)
143 if ((header & (3<<17)) == 0)
146 if ((header & (0xf<<12)) == 0xf<<12)
149 if ((header & (3<<10)) == 3<<10)
154 #endif /* AVCODEC_MPEGAUDIO_H */