lib/lame/VbrTag.h

   1 /*
   2  *      Xing VBR tagging for LAME.
   3  *
   4  *      Copyright (c) 1999 A.L. Faber
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Library General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2 of the License, or (at your option) any later version.
  10  *
  11  * This library 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  * Library General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Library General Public
  17  * License along with this library; if not, write to the
  18  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  19  * Boston, MA 02111-1307, USA.
  20  */
  21
  22 #ifndef LAME_VRBTAG_H
  23 #define LAME_VRBTAG_H
  24 #include "lame.h"
  25 /* -----------------------------------------------------------
  26  * A Vbr header may be present in the ancillary
  27  * data field of the first frame of an mp3 bitstream
  28  * The Vbr header (optionally) contains
  29  *      frames      total number of audio frames in the bitstream
  30  *      bytes       total number of bytes in the bitstream
  31  *      toc         table of contents
  32
  33  * toc (table of contents) gives seek points
  34  * for random access
  35  * the ith entry determines the seek point for
  36  * i-percent duration
  37  * seek point in bytes = (toc[i]/256.0) * total_bitstream_bytes
  38  * e.g. half duration seek point = (toc[50]/256.0) * total_bitstream_bytes
  39  */
  40
  41
  42 #define FRAMES_FLAG     0x0001
  43 #define BYTES_FLAG      0x0002
  44 #define TOC_FLAG        0x0004
  45 #define VBR_SCALE_FLAG  0x0008
  46
  47 #define NUMTOCENTRIES 100
  48
  49 #define FRAMES_AND_BYTES (FRAMES_FLAG | BYTES_FLAG)
  50
  51
  52
  53 /*structure to receive extracted header */
  54 /* toc may be NULL*/
  55 typedef struct
  56 {
  57   int           h_id;                   /* from MPEG header, 0=MPEG2, 1=MPEG1 */
  58   int           samprate;               /* determined from MPEG header */
  59   int           flags;                  /* from Vbr header data */
  60   int           frames;                 /* total bit stream frames from Vbr header data */
  61   int           bytes;                  /* total bit stream bytes from Vbr header data*/
  62   int           vbr_scale;              /* encoded vbr scale from Vbr header data*/
  63   unsigned char toc[NUMTOCENTRIES];     /* may be NULL if toc not desired*/
  64   int           headersize;             /* size of VBR header, in bytes */
  65   int           enc_delay;              /* encoder delay */
  66   int           enc_padding;            /* encoder paddign added at end of stream */
  67 }   VBRTAGDATA;
  68
  69 int CheckVbrTag(unsigned char *buf);
  70 int GetVbrTag(VBRTAGDATA *pTagData,  unsigned char *buf);
  71
  72 int SeekPoint(unsigned char TOC[NUMTOCENTRIES], int file_bytes, float percent);
  73 int InitVbrTag(lame_global_flags *gfp);
  74 int PutVbrTag(lame_global_flags *gfp,FILE *fid,int nVbrScale);
  75 int PutLameVBR(lame_global_flags *gfp, FILE *fpStream, uint8_t *pbtStreamBuffer, uint32_t id3v2size,  uint16_t crc);
  76 void AddVbrFrame(lame_global_flags *gfp);
  77 void ReportLameTagProgress(lame_global_flags *gfp,int nStart);
  78 void UpdateMusicCRC(uint16_t *crc,unsigned char *buffer, int size);
  79
  80 #endif