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 } VBRTAGDATA; 66 67 int CheckVbrTag(unsigned char *buf); 68 int GetVbrTag(VBRTAGDATA *pTagData, unsigned char *buf); 69 70 int SeekPoint(unsigned char TOC[NUMTOCENTRIES], int file_bytes, float percent); 71 int InitVbrTag(lame_global_flags *gfp); 72 int PutVbrTag(lame_global_flags *gfp,FILE *fid,int nVbrScale); 73 void AddVbrFrame(lame_global_flags *gfp); 74 75 76 #endif 77