/*---- DXhead.h -------------------------------------------- decoder MPEG Layer III handle Xing header Copyright 1998 Xing Technology Corp. -----------------------------------------------------------*/ // A Xing header may be present in the ancillary // data field of the first frame of an mp3 bitstream // The Xing header (optionally) contains // frames total number of audio frames in the bitstream // bytes total number of bytes in the bitstream // toc table of contents // toc (table of contents) gives seek points // for random access // the ith entry determines the seek point for // i-percent duration // seek point in bytes = (toc[i]/256.0) * total_bitstream_bytes // e.g. half duration seek point = (toc[50]/256.0) * total_bitstream_bytes #define FRAMES_FLAG 0x0001 #define BYTES_FLAG 0x0002 #define TOC_FLAG 0x0004 #define VBR_SCALE_FLAG 0x0008 #define FRAMES_AND_BYTES (FRAMES_FLAG | BYTES_FLAG) int SeekPoint(unsigned char TOC[100], int file_bytes, float percent); // return seekpoint in bytes (may be at eof if percent=100.0) // TOC = table of contents from Xing header // file_bytes = number of bytes in mp3 file // percent = play time percentage of total playtime. May be // fractional (e.g. 87.245)
