ref: 19b81b0cb9c82430a01c4806543a580d3b656dd0
dir: /plugins/xmms/src/aac_utils.c/
/* * * utils for AAC informations */ #include <glib.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #define ADTS_HEADER_SIZE 8 #define SEEK_TABLE_CHUNK 60 #define MPEG4_TYPE 0 #define MPEG2_TYPE 1 // Read ADTS header, the file descriptor must be at // the begining of the aac frame not at the id3tag int getAacInfo(FILE *fd) { unsigned char header[ADTS_HEADER_SIZE]; unsigned int id; unsigned long originPosition; originPosition = ftell(fd); if(fread(header, 1, ADTS_HEADER_SIZE, fd) != ADTS_HEADER_SIZE){ fseek(fd, originPosition, SEEK_SET); return(-1); } if(!((header[0]==0xFF)&&((header[1]& 0xF6)==0xF0))){ printf("Bad header\n"); return(-1); } id = header[1]&0x08; if(id==0){//MPEG-4 AAC fseek(fd, originPosition, SEEK_SET); return(MPEG4_TYPE); }else{ fseek(fd, originPosition, SEEK_SET); return(MPEG2_TYPE); } fseek(fd, originPosition, SEEK_SET); return(-1); } // as AAC is VBR we need to check all ADTS header // to enable seeking... // there is no other solution void checkADTSForSeeking(FILE *fd, unsigned long **seekTable, unsigned long *seekTableLength) { unsigned long originPosition; unsigned long position; unsigned char header[ADTS_HEADER_SIZE]; unsigned int frameCount, frameLength, frameInsec; unsigned int id=0, seconds=0; originPosition = ftell(fd); for(frameCount=0,frameInsec=0;; frameCount++,frameInsec++){ position = ftell(fd); if(fread(header, 1, ADTS_HEADER_SIZE, fd)!=ADTS_HEADER_SIZE){ break; } if(!strncmp(header, "ID3", 3)){ break; } if(!((header[0]==0xFF)&&((header[1]& 0xF6)==0xF0))){ printf("error : Bad 1st header, file may be corrupt !\n"); break; } if(!frameCount){ id=header[1]&0x08; if(((*seekTable) = malloc(SEEK_TABLE_CHUNK * sizeof(unsigned long)))==0){ printf("malloc error\n"); return; } (*seekTableLength) = SEEK_TABLE_CHUNK; } //if(id==0){//MPEG-4 //frameLength = ((unsigned int)header[4]<<5)|((unsigned int)header[5]>>3); //}else{//MPEG-2 frameLength = (((unsigned int)header[3]&0x3)<<11)|((unsigned int)header[4]<<3)|(header[5]>>5); //} if(frameInsec==43){//??? frameInsec=0; } if(frameInsec==0){ if(seconds == (*seekTableLength)){ (*seekTable) = realloc((*seekTable), (seconds+SEEK_TABLE_CHUNK)*sizeof(unsigned long)); (*seekTableLength) = seconds+SEEK_TABLE_CHUNK; } (*seekTable)[seconds] = position; seconds++; } if(fseek(fd, frameLength-ADTS_HEADER_SIZE, SEEK_CUR)==-1){ break; } } (*seekTableLength) = seconds; fseek(fd, originPosition, SEEK_SET); }