ref: 588f58881659672f919dd91027e408f12ad3a05a
dir: /plugins/in_mp4/aacinfo.c/
/*
** 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 1.6 2004/10/18 19:25:00 menno Exp $
**/
#define WIN32_LEAN_AND_MEAN
#include <windows.h>
#include <malloc.h>
#include <stdlib.h>
#include <stdio.h>
#include <math.h>
#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;
}