mp3tech.h

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/*
    mp3tech.h - Headers for mp3tech.c

    Copyright (C) 2000-2006 Cedric Tefft <cedric@phreaker.net>

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program 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 General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

  ***************************************************************************

  This file is based in part on:

        * MP3Info 0.5 by Ricardo Cerqueira <rmc@rccn.net>
        * MP3Stat 0.9 by Ed Sweetman <safemode@voicenet.com> and 
                         Johannes Overmann <overmann@iname.com>

*/

/* MIN_CONSEC_GOOD_FRAMES defines how many consecutive valid MP3 frames
   we need to see before we decide we are looking at a real MP3 file */
#define MIN_CONSEC_GOOD_FRAMES 4
#define FRAME_HEADER_SIZE 4
#define MIN_FRAME_SIZE 21
#define NUM_SAMPLES 4

enum VBR_REPORT { VBR_VARIABLE, VBR_AVERAGE, VBR_MEDIAN };
enum SCANTYPE { SCAN_NONE, SCAN_QUICK, SCAN_FULL };

typedef struct {
        unsigned long   sync;
        unsigned int    version;
        unsigned int    layer;
        unsigned int    crc;
        unsigned int    bitrate;
        unsigned int    freq;
        unsigned int    padding;
        unsigned int    extension;
        unsigned int    mode;
        unsigned int    mode_extension;
        unsigned int    copyright;
        unsigned int    original;
        unsigned int    emphasis;
} mp3header;

typedef struct {
        char title[31];
        char artist[31];
        char album[31];
        char year[5];
        char comment[31];
        unsigned char track[1];
        unsigned char genre[1];
} id3tag;

typedef struct {
        char *filename;
        FILE *file;
        off_t datasize;
        int header_isvalid;
        mp3header header;
        int id3_isvalid;
        id3tag id3;
        int vbr;
        float vbr_average;
        int seconds;
        int frames;
        int badframes;
} mp3info;


int get_header(FILE *file,mp3header *header);
int frame_length(mp3header *header);
int header_layer(mp3header *h);
int header_bitrate(mp3header *h);
int sameConstant(mp3header *h1, mp3header *h2);
int get_mp3_info(mp3info *mp3,int scantype, int fullscan_vbr);
int get_id3(mp3info *mp3);
char *pad(char *string, int length);
char *unpad(char *string);
int write_tag(mp3info *mp3);
int header_frequency(mp3header *h);
char *header_emphasis(mp3header *h);
char *header_mode(mp3header *h);
int get_first_header(mp3info *mp3,long startpos);
int get_next_header(mp3info *mp3);