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/*C
(c) 2005 bl0rg.net
**/
#ifndef MP3_H__
#define MP3_H__
/*M
\emph{Size allocated for the ''raw'' content of an MP3 frame.}
This is an arbitrary size.
**/
#define MP3_RAW_SIZE 4000
/*M
\emph{Maximal number of synchronisation errors allowed while
reading an MP3 stream.}
**/
#define MP3_MAX_SYNC 4000
/*M
\emph{MPEG Audio Frame Header size.}
**/
#define MP3_HDR_SIZE 4
/*M
\emph{Scalefactor information contained in a single granule.}
**/
typedef struct {
unsigned int l[23]; /* long window */
unsigned int s[3][13]; /* short window */
} mp3_sf_t;
typedef struct {
int s;
float x;
} mp3_sample_t;
/*M
\emph{MP3 granule.}
**/
typedef struct mp3_granule_s {
int part2_3_length;
int part2_length;
int part3_length;
unsigned int big_values;
unsigned int global_gain;
unsigned int scale_comp;
unsigned int slen0;
unsigned int slen1;
unsigned int blocksplit_flag;
unsigned int block_type;
unsigned int switch_point;
unsigned int tbl_sel[3];
unsigned int reg0_cnt;
unsigned int reg1_cnt;
unsigned int sub_gain[3];
unsigned int maxband[3];
unsigned int maxbandl;
unsigned int maxb;
unsigned int region1start;
unsigned int region2start;
unsigned int preflag;
unsigned int scale_scale;
unsigned int cnt1tbl_sel;
float *full_gain[3];
float *pow2gain;
mp3_sf_t sf; /* scale factor */
mp3_sample_t samples[576];
} mp3_granule_t;
/*M
\emph{MP3 stereo channel.}
**/
typedef struct mp3_channel_s {
unsigned char scfsi[4];
mp3_granule_t granule[2];
} mp3_channel_t;
/*M
\emph{MP3 side information.}
In mono MP3s only the first channel structure is used.
**/
typedef struct mp3_si_s {
unsigned int main_data_end;
unsigned int private_bits;
mp3_channel_t channel[2];
} mp3_si_t;
/*M
\emph{Single MP3 frame.}
**/
typedef struct mp3_frame_s {
unsigned char id;
unsigned char layer;
unsigned char protected;
unsigned char bitrate_index;
unsigned char samplerfindex;
unsigned char padding_bit;
unsigned char private_bit;
unsigned char mode;
unsigned char mode_ext;
unsigned char copyright;
unsigned char original;
unsigned char emphasis;
unsigned char crc[2];
mp3_si_t si;
unsigned long si_size;
unsigned long si_bitsize;
unsigned long adu_bitsize;
unsigned long adu_size;
/* calculated information */
unsigned short syncskip;
unsigned long bitrate;
unsigned long samplerate;
unsigned long samplelen;
unsigned long frame_size;
unsigned long frame_data_size;
unsigned long usec;
/* XXX add length counter for overflow checking */
unsigned char raw[MP3_RAW_SIZE];
} mp3_frame_t;
/*M
\emph{Prototypes and macros.}
**/
#define mp3_frame_data_begin(f) \
((f)->raw + 4 + ((f)->protected ? 0 : 2) + (f)->si_size)
#include "file.h"
int mp3_read_si(mp3_frame_t *frame);
int mp3_read_hdr(mp3_frame_t *frame);
int mp3_read_sf(mp3_frame_t *frame);
int mp3_next_frame(file_t *mp3, mp3_frame_t *frame);
int mp3_unpack(mp3_frame_t *frame);
int mp3_fill_si(mp3_frame_t *frame);
int mp3_fill_hdr(mp3_frame_t *frame);
int mp3_write_frame(file_t *file, mp3_frame_t *frame);
int mp3_trans_frame(mp3_frame_t *frame);
void mp3_calc_hdr(mp3_frame_t *frame);
unsigned long mp3_frame_size(mp3_frame_t *frame);
/*M
**/
#endif /* MP3_H__ */
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