/* ** FAAD2 - Freeware Advanced Audio (AAC) Decoder including SBR decoding ** Copyright (C) 2003 M. Bakker, Ahead Software AG, http://www.nero.com ** ** 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. ** ** Any non-GPL usage of this software or parts of this software is strictly ** forbidden. ** ** Commercial non-GPL licensing of this software is possible. ** For more info contact Ahead Software through Mpeg4AAClicense@nero.com. ** ** $Id: aacinfo.c,v 1.3 2003/12/06 04:24:17 rjamorim Exp $ **/ #define WIN32_LEAN_AND_MEAN #include #include #include #include #include "aacinfo.h" #include "utils.h" #define ADIF_MAX_SIZE 30 /* Should be enough */ #define ADTS_MAX_SIZE 10 /* Should be enough */ static int sample_rates[] = {96000,88200,64000,48000,44100,32000,24000,22050,16000,12000,11025,8000}; static int read_ADIF_header(FILE *file, faadAACInfo *info) { int bitstream; unsigned char buffer[ADIF_MAX_SIZE]; int skip_size = 0; int sf_idx; /* Get ADIF header data */ info->headertype = 1; if (fread(buffer, 1, ADIF_MAX_SIZE, file) != ADIF_MAX_SIZE) return -1; /* copyright string */ if(buffer[0] & 0x80) skip_size += 9; /* skip 9 bytes */ bitstream = buffer[0 + skip_size] & 0x10; info->bitrate = ((unsigned int)(buffer[0 + skip_size] & 0x0F)<<19)| ((unsigned int)buffer[1 + skip_size]<<11)| ((unsigned int)buffer[2 + skip_size]<<3)| ((unsigned int)buffer[3 + skip_size] & 0xE0); if (bitstream == 0) { info->object_type = ((buffer[6 + skip_size]&0x01)<<1)|((buffer[7 + skip_size]&0x80)>>7); sf_idx = (buffer[7 + skip_size]&0x78)>>3; } else { info->object_type = (buffer[4 + skip_size] & 0x18)>>3; sf_idx = ((buffer[4 + skip_size] & 0x07)<<1)|((buffer[5 + skip_size] & 0x80)>>7); } info->sampling_rate = sample_rates[sf_idx]; return 0; } static int read_ADTS_header(FILE *file, faadAACInfo *info) { /* Get ADTS header data */ unsigned char buffer[ADTS_MAX_SIZE]; int frames, t_framelength = 0, frame_length, sr_idx = 0, ID; int second = 0, pos; float frames_per_sec = 0; unsigned long bytes; unsigned long *tmp_seek_table = NULL; info->headertype = 2; /* Read all frames to ensure correct time and bitrate */ for (frames = 0; /* */; frames++) { bytes = fread(buffer, 1, ADTS_MAX_SIZE, file); if (bytes != ADTS_MAX_SIZE) break; /* check syncword */ if (!((buffer[0] == 0xFF)&&((buffer[1] & 0xF6) == 0xF0))) break; if (!frames) { /* fixed ADTS header is the same for every frame, so we read it only once */ /* Syncword found, proceed to read in the fixed ADTS header */ ID = buffer[1] & 0x08; info->object_type = (buffer[2]&0xC0)>>6; sr_idx = (buffer[2]&0x3C)>>2; info->channels = ((buffer[2]&0x01)<<2)|((buffer[3]&0xC0)>>6); frames_per_sec = sample_rates[sr_idx] / 1024.f; } /* ...and the variable ADTS header */ if (ID == 0) { info->version = 4; } else { /* MPEG-2 */ info->version = 2; } frame_length = ((((unsigned int)buffer[3] & 0x3)) << 11) | (((unsigned int)buffer[4]) << 3) | (buffer[5] >> 5); t_framelength += frame_length; pos = ftell(file) - ADTS_MAX_SIZE; fseek(file, frame_length - ADTS_MAX_SIZE, SEEK_CUR); } if (frames > 0) { float sec_per_frame, bytes_per_frame; info->sampling_rate = sample_rates[sr_idx]; sec_per_frame = (float)info->sampling_rate/1024.0; bytes_per_frame = (float)t_framelength / (float)frames; info->bitrate = 8 * (int)floor(bytes_per_frame * sec_per_frame); info->length = (int)floor((float)frames/frames_per_sec)*1000; } else { info->sampling_rate = 4; info->bitrate = 128000; info->length = 0; info->channels = 0; } return 0; } int get_AAC_format(char *filename, faadAACInfo *info) { unsigned long tagsize; FILE *file; char buffer[10]; unsigned long file_len; unsigned char adxx_id[5]; unsigned long tmp; memset(info, 0, sizeof(faadAACInfo)); file = fopen(filename, "rb"); if(file == NULL) return -1; fseek(file, 0, SEEK_END); file_len = ftell(file); fseek(file, 0, SEEK_SET); /* Skip the tag, if it's there */ tmp = fread(buffer, 10, 1, file); if (StringComp(buffer, "ID3", 3) == 0) { /* high bit is not used */ tagsize = (buffer[6] << 21) | (buffer[7] << 14) | (buffer[8] << 7) | (buffer[9] << 0); fseek(file, tagsize, SEEK_CUR); tagsize += 10; } else { tagsize = 0; fseek(file, 0, SEEK_SET); } if (file_len) file_len -= tagsize; tmp = fread(adxx_id, 2, 1, file); adxx_id[5-1] = 0; info->length = 0; /* Determine the header type of the file, check the first two bytes */ if (StringComp(adxx_id, "AD", 2) == 0) { /* We think its an ADIF header, but check the rest just to make sure */ tmp = fread(adxx_id + 2, 2, 1, file); if (StringComp(adxx_id, "ADIF", 4) == 0) { read_ADIF_header(file, info); info->length = (int)((float)file_len*8000.0/((float)info->bitrate)); } } else { /* No ADIF, check for ADTS header */ if ((adxx_id[0] == 0xFF)&&((adxx_id[1] & 0xF6) == 0xF0)) { /* ADTS header located */ fseek(file, tagsize, SEEK_SET); read_ADTS_header(file, info); } else { /* Unknown/headerless AAC file, assume format: */ info->version = 2; info->bitrate = 128000; info->sampling_rate = 44100; info->channels = 2; info->headertype = 0; info->object_type = 1; } } fclose(file); return 0; }