Libav
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00001 /* 00002 * copyright (c) 2001 Fabrice Bellard 00003 * 00004 * This file is part of FFmpeg. 00005 * 00006 * FFmpeg is free software; you can redistribute it and/or 00007 * modify it under the terms of the GNU Lesser General Public 00008 * License as published by the Free Software Foundation; either 00009 * version 2.1 of the License, or (at your option) any later version. 00010 * 00011 * FFmpeg is distributed in the hope that it will be useful, 00012 * but WITHOUT ANY WARRANTY; without even the implied warranty of 00013 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 00014 * Lesser General Public License for more details. 00015 * 00016 * You should have received a copy of the GNU Lesser General Public 00017 * License along with FFmpeg; if not, write to the Free Software 00018 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 00019 */ 00020 00026 #ifndef AVCODEC_MPEGAUDIO_H 00027 #define AVCODEC_MPEGAUDIO_H 00028 00029 #include "avcodec.h" 00030 #include "get_bits.h" 00031 #include "dsputil.h" 00032 00033 #define CONFIG_AUDIO_NONSHORT 0 00034 00035 /* max frame size, in samples */ 00036 #define MPA_FRAME_SIZE 1152 00037 00038 /* max compressed frame size */ 00039 #define MPA_MAX_CODED_FRAME_SIZE 1792 00040 00041 #define MPA_MAX_CHANNELS 2 00042 00043 #define SBLIMIT 32 /* number of subbands */ 00044 00045 #define MPA_STEREO 0 00046 #define MPA_JSTEREO 1 00047 #define MPA_DUAL 2 00048 #define MPA_MONO 3 00049 00050 /* header + layer + bitrate + freq + lsf/mpeg25 */ 00051 #define SAME_HEADER_MASK \ 00052 (0xffe00000 | (3 << 17) | (0xf << 12) | (3 << 10) | (3 << 19)) 00053 00054 #define MP3_MASK 0xFFFE0CCF 00055 00056 #if CONFIG_MPEGAUDIO_HP 00057 #define FRAC_BITS 23 /* fractional bits for sb_samples and dct */ 00058 #define WFRAC_BITS 16 /* fractional bits for window */ 00059 #else 00060 #define FRAC_BITS 15 /* fractional bits for sb_samples and dct */ 00061 #define WFRAC_BITS 14 /* fractional bits for window */ 00062 #endif 00063 00064 #define FRAC_ONE (1 << FRAC_BITS) 00065 00066 #define FIX(a) ((int)((a) * FRAC_ONE)) 00067 00068 #if CONFIG_MPEGAUDIO_HP && CONFIG_AUDIO_NONSHORT 00069 typedef int32_t OUT_INT; 00070 #define OUT_MAX INT32_MAX 00071 #define OUT_MIN INT32_MIN 00072 #define OUT_SHIFT (WFRAC_BITS + FRAC_BITS - 31) 00073 #define OUT_FMT SAMPLE_FMT_S32 00074 #else 00075 typedef int16_t OUT_INT; 00076 #define OUT_MAX INT16_MAX 00077 #define OUT_MIN INT16_MIN 00078 #define OUT_SHIFT (WFRAC_BITS + FRAC_BITS - 15) 00079 #define OUT_FMT SAMPLE_FMT_S16 00080 #endif 00081 00082 #if FRAC_BITS <= 15 00083 typedef int16_t MPA_INT; 00084 #else 00085 typedef int32_t MPA_INT; 00086 #endif 00087 00088 #define BACKSTEP_SIZE 512 00089 #define EXTRABYTES 24 00090 00091 /* layer 3 "granule" */ 00092 typedef struct GranuleDef { 00093 uint8_t scfsi; 00094 int part2_3_length; 00095 int big_values; 00096 int global_gain; 00097 int scalefac_compress; 00098 uint8_t block_type; 00099 uint8_t switch_point; 00100 int table_select[3]; 00101 int subblock_gain[3]; 00102 uint8_t scalefac_scale; 00103 uint8_t count1table_select; 00104 int region_size[3]; /* number of huffman codes in each region */ 00105 int preflag; 00106 int short_start, long_end; /* long/short band indexes */ 00107 uint8_t scale_factors[40]; 00108 int32_t sb_hybrid[SBLIMIT * 18]; /* 576 samples */ 00109 } GranuleDef; 00110 00111 #define MPA_DECODE_HEADER \ 00112 int frame_size; \ 00113 int error_protection; \ 00114 int layer; \ 00115 int sample_rate; \ 00116 int sample_rate_index; /* between 0 and 8 */ \ 00117 int bit_rate; \ 00118 int nb_channels; \ 00119 int mode; \ 00120 int mode_ext; \ 00121 int lsf; 00122 00123 typedef struct MPADecodeHeader { 00124 MPA_DECODE_HEADER 00125 } MPADecodeHeader; 00126 00127 typedef struct MPADecodeContext { 00128 MPA_DECODE_HEADER 00129 uint8_t last_buf[2*BACKSTEP_SIZE + EXTRABYTES]; 00130 int last_buf_size; 00131 /* next header (used in free format parsing) */ 00132 uint32_t free_format_next_header; 00133 GetBitContext gb; 00134 GetBitContext in_gb; 00135 DECLARE_ALIGNED(16, MPA_INT, synth_buf)[MPA_MAX_CHANNELS][512 * 2]; 00136 int synth_buf_offset[MPA_MAX_CHANNELS]; 00137 DECLARE_ALIGNED(16, int32_t, sb_samples)[MPA_MAX_CHANNELS][36][SBLIMIT]; 00138 int32_t mdct_buf[MPA_MAX_CHANNELS][SBLIMIT * 18]; /* previous samples, for layer 3 MDCT */ 00139 GranuleDef granules[2][2]; /* Used in Layer 3 */ 00140 #ifdef DEBUG 00141 int frame_count; 00142 #endif 00143 void (*compute_antialias)(struct MPADecodeContext *s, struct GranuleDef *g); 00144 int adu_mode; 00145 int dither_state; 00146 int error_recognition; 00147 AVCodecContext* avctx; 00148 } MPADecodeContext; 00149 00150 /* layer 3 huffman tables */ 00151 typedef struct HuffTable { 00152 int xsize; 00153 const uint8_t *bits; 00154 const uint16_t *codes; 00155 } HuffTable; 00156 00157 int ff_mpa_l2_select_table(int bitrate, int nb_channels, int freq, int lsf); 00158 int ff_mpa_decode_header(AVCodecContext *avctx, uint32_t head, int *sample_rate, int *channels, int *frame_size, int *bitrate); 00159 extern MPA_INT ff_mpa_synth_window[]; 00160 void ff_mpa_synth_init(MPA_INT *window); 00161 void ff_mpa_synth_filter(MPA_INT *synth_buf_ptr, int *synth_buf_offset, 00162 MPA_INT *window, int *dither_state, 00163 OUT_INT *samples, int incr, 00164 int32_t sb_samples[SBLIMIT]); 00165 00166 /* fast header check for resync */ 00167 static inline int ff_mpa_check_header(uint32_t header){ 00168 /* header */ 00169 if ((header & 0xffe00000) != 0xffe00000) 00170 return -1; 00171 /* layer check */ 00172 if ((header & (3<<17)) == 0) 00173 return -1; 00174 /* bit rate */ 00175 if ((header & (0xf<<12)) == 0xf<<12) 00176 return -1; 00177 /* frequency */ 00178 if ((header & (3<<10)) == 3<<10) 00179 return -1; 00180 return 0; 00181 } 00182 00183 #endif /* AVCODEC_MPEGAUDIO_H */