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owntone-server/src/scan-aac.c

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/*
* $Id$
*
* Copyright (C) 2003 Ron Pedde (ron@pedde.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
*/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include <fcntl.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <sys/time.h>
#include "err.h"
#include "mp3-scanner.h"
#include "scan-aac.h"
/* Forwards */
time_t scan_aac_mac_to_unix_time(int t);
/**
* Convert mac time to unix time (different epochs)
*
* @param t time since mac epoch
* @returns time since unix epoch
*/
time_t scan_aac_mac_to_unix_time(int t) {
struct timeval tv;
struct timezone tz;
gettimeofday(&tv, &tz);
return (t - (365L * 66L * 24L * 60L * 60L + 17L * 60L * 60L * 24L) +
(tz.tz_minuteswest * 60));
}
/**
* Returns the offset of the atom specified by the given path or -1 if
* not found. atom_path is a colon separated list of atoms specifying
* a path from parent node to the target node. All paths must be specified
* from the root.
*
* @param aac_fp the aac file being searched
* @param atom_path the colon separated list of atoms
* @param atom_length the size of the atom "drilled to"
* @returns offset of the atom, or -1 if unsuccessful
*/
off_t scan_aac_drilltoatom(FILE *aac_fp,char *atom_path,
unsigned int *atom_length) {
long atom_offset;
off_t file_size;
char *cur_p, *end_p;
char atom_name[5];
fseek(aac_fp, 0, SEEK_END);
file_size = ftell(aac_fp);
rewind(aac_fp);
end_p = atom_path;
while (*end_p != '\0') {
end_p++;
}
atom_name[4] = '\0';
cur_p = atom_path;
while (cur_p != NULL) {
if ((end_p - cur_p) < 4) {
return -1;
}
strncpy(atom_name, cur_p, 4);
atom_offset = scan_aac_findatom(aac_fp, file_size,
atom_name, atom_length);
if (atom_offset == -1) {
return -1;
}
DPRINTF(E_SPAM,L_SCAN,"Found %s atom at off %ld.\n",
atom_name, ftell(aac_fp) - 8);
cur_p = strchr(cur_p, ':');
if (cur_p != NULL) {
cur_p++;
/* FIXME
* Hack to deal with atoms that have extra data in addition
* to having child atoms. This should be dealt in a better fashion
* than this (table with skip offsets or a real mp4 parser.) */
if (!strcmp(atom_name, "meta")) {
fseek(aac_fp, 4, SEEK_CUR);
} else if (!strcmp(atom_name, "stsd")) {
fseek(aac_fp, 8, SEEK_CUR);
} else if (!strcmp(atom_name, "mp4a")) {
fseek(aac_fp, 28, SEEK_CUR);
}
}
}
return ftell(aac_fp) - 8;
}
/**
* Given a file, search for a particular aac atom.
*
* @param fin file handle of the open aac file
* @param max_offset how far to search (probably size of container atom)
* @param which_atom what atom name we are searching for
* @param atom_size this will hold the size of the atom found
*/
long scan_aac_findatom(FILE *fin, long max_offset,
char *which_atom, unsigned int *atom_size) {
long current_offset=0;
int size;
char atom[4];
while(current_offset < max_offset) {
if(fread((void*)&size,1,sizeof(int),fin) != sizeof(int))
return -1;
size=ntohl(size);
if(size <= 7) /* something not right */
return -1;
if(fread(atom,1,4,fin) != 4)
return -1;
if(strncasecmp(atom,which_atom,4) == 0) {
*atom_size=size;
return current_offset;
}
fseek(fin,size-8,SEEK_CUR);
current_offset+=size;
}
return -1;
}
/**
* main aac scanning routing.
*
* @param filename file to scan
* @param pmp3 pointer to the MP3FILE to fill with data
* @returns FALSE if file should not be added to database, TRUE otherwise
*/
int scan_get_aacinfo(char *filename, MP3FILE *pmp3) {
FILE *fin;
long atom_offset;
unsigned int atom_length;
long current_offset=0;
int current_size;
char current_atom[4];
char *current_data;
unsigned short us_data;
int genre;
int len;
int sample_size;
int samples;
unsigned int bit_rate;
int ms;
unsigned char buffer[2];
int time = 0;
if(!(fin=fopen(filename,"rb"))) {
DPRINTF(E_INF,L_SCAN,"Cannot open file %s for reading\n",filename);
return FALSE;
}
fseek(fin,0,SEEK_END);
pmp3->file_size = ftell(fin);
fseek(fin,0,SEEK_SET);
atom_offset=scan_aac_drilltoatom(fin, "moov:udta:meta:ilst", &atom_length);
if(atom_offset != -1) {
/* found the tag section - need to walk through now */
while(current_offset < atom_length) {
if(fread((void*)&current_size,1,sizeof(int),fin) != sizeof(int))
break;
current_size=ntohl(current_size);
if(current_size <= 7) /* something not right */
break;
if(fread(current_atom,1,4,fin) != 4)
break;
len=current_size-7; /* for ill-formed too-short tags */
if(len < 22)
len=22;
current_data=(char*)malloc(len); /* extra byte */
memset(current_data,0x00,len);
if(fread(current_data,1,current_size-8,fin) != current_size-8)
break;
if(!memcmp(current_atom,"\xA9" "nam",4)) { /* Song name */
pmp3->title=strdup((char*)&current_data[16]);
} else if(!memcmp(current_atom,"\xA9" "ART",4)) {
pmp3->artist=strdup((char*)&current_data[16]);
} else if(!memcmp(current_atom,"\xA9" "alb",4)) {
pmp3->album=strdup((char*)&current_data[16]);
} else if(!memcmp(current_atom,"\xA9" "cmt",4)) {
pmp3->comment=strdup((char*)&current_data[16]);
} else if(!memcmp(current_atom,"\xA9" "wrt",4)) {
pmp3->composer=strdup((char*)&current_data[16]);
} else if(!memcmp(current_atom,"\xA9" "grp",4)) {
pmp3->grouping=strdup((char*)&current_data[16]);
} else if(!memcmp(current_atom,"\xA9" "gen",4)) {
/* can this be a winamp genre??? */
pmp3->genre=strdup((char*)&current_data[16]);
} else if(!memcmp(current_atom,"tmpo",4)) {
us_data=*((unsigned short *)&current_data[16]);
us_data=ntohs(us_data);
pmp3->bpm=us_data;
} else if(!memcmp(current_atom,"trkn",4)) {
us_data=*((unsigned short *)&current_data[18]);
us_data=ntohs(us_data);
pmp3->track=us_data;
us_data=*((unsigned short *)&current_data[20]);
us_data=ntohs(us_data);
pmp3->total_tracks=us_data;
} else if(!memcmp(current_atom,"disk",4)) {
us_data=*((unsigned short *)&current_data[18]);
us_data=ntohs(us_data);
pmp3->disc=us_data;
us_data=*((unsigned short *)&current_data[20]);
us_data=ntohs(us_data);
pmp3->total_discs=us_data;
} else if(!memcmp(current_atom,"\xA9" "day",4)) {
pmp3->year=atoi((char*)&current_data[16]);
} else if(!memcmp(current_atom,"gnre",4)) {
genre=(int)(*((char*)&current_data[17]));
genre--;
if((genre < 0) || (genre > WINAMP_GENRE_UNKNOWN))
genre=WINAMP_GENRE_UNKNOWN;
pmp3->genre=strdup(scan_winamp_genre[genre]);
} else if (!memcmp(current_atom, "cpil", 4)) {
pmp3->compilation = current_data[16];
}
free(current_data);
current_offset+=current_size;
}
}
/* got the tag info, now let's get bitrate, etc */
atom_offset = scan_aac_drilltoatom(fin, "moov:mvhd", &atom_length);
if(atom_offset != -1) {
fseek(fin, 4, SEEK_CUR);
fread((void *)&time, sizeof(int), 1, fin);
time = ntohl(time);
pmp3->time_added = scan_aac_mac_to_unix_time(time);
fread((void *)&time, sizeof(int), 1, fin);
time = ntohl(time);
pmp3->time_modified = scan_aac_mac_to_unix_time(time);
fread((void*)&sample_size,1,sizeof(int),fin);
fread((void*)&samples,1,sizeof(int),fin);
sample_size=ntohl(sample_size);
samples=ntohl(samples);
/* avoid overflowing on large sample_sizes (90000) */
ms=1000;
while((ms > 9) && (!(sample_size % 10))) {
sample_size /= 10;
ms /= 10;
}
/* DWB: use ms time instead of sec */
pmp3->song_length=(int)((samples * ms) / sample_size);
DPRINTF(E_DBG,L_SCAN,"Song length: %d seconds\n",
pmp3->song_length / 1000);
}
pmp3->bitrate = 0;
/* see if it is aac or alac */
atom_offset = scan_aac_drilltoatom(fin,
"moov:trak:mdia:minf:stbl:stsd:alac",
&atom_length);
if(atom_offset != -1) {
/* should we still pull samplerate, etc from the this atom? */
if(pmp3->codectype) {
free(pmp3->codectype);
}
pmp3->codectype=strdup("alac");
}
/* Get the sample rate from the 'mp4a' atom (timescale). This is also
found in the 'mdhd' atom which is a bit closer but we need to
navigate to the 'mp4a' atom anyways to get to the 'esds' atom. */
atom_offset=scan_aac_drilltoatom(fin,
"moov:trak:mdia:minf:stbl:stsd:mp4a",
&atom_length);
if (atom_offset != -1) {
fseek(fin, atom_offset + 32, SEEK_SET);
/* Timescale here seems to be 2 bytes here (the 2 bytes before it are
* "reserved") though the timescale in the 'mdhd' atom is 4. Not sure
* how this is dealt with when sample rate goes higher than 64K. */
fread(buffer, sizeof(unsigned char), 2, fin);
pmp3->samplerate = (buffer[0] << 8) | (buffer[1]);
/* Seek to end of atom. */
fseek(fin, 2, SEEK_CUR);
/* Get the bit rate from the 'esds' atom. We are already positioned
in the parent atom so just scan ahead. */
atom_offset = scan_aac_findatom(fin,
atom_length-(ftell(fin)-atom_offset),
"esds", &atom_length);
if (atom_offset != -1) {
/* Roku Soundbridge seems to believe anything above 320K is
* an ALAC encoded m4a. We'll lie on their behalf.
*/
fseek(fin, atom_offset + 22, SEEK_CUR);
fread((void *)&bit_rate, sizeof(unsigned int), 1, fin);
pmp3->bitrate = ntohl(bit_rate) / 1000;
DPRINTF(E_DBG,L_SCAN,"esds bitrate: %d\n",pmp3->bitrate);
if(pmp3->bitrate > 320) {
pmp3->bitrate = 320;
}
} else {
DPRINTF(E_DBG,L_SCAN, "Couldn't find 'esds' atom for bit rate.\n");
}
} else {
DPRINTF(E_DBG,L_SCAN, "Couldn't find 'mp4a' atom for sample rate.\n");
}
/* Fallback if we can't find the info in the atoms. */
if (pmp3->bitrate == 0) {
/* calculate bitrate from song length... Kinda cheesy */
DPRINTF(E_DBG,L_SCAN, "Guesstimating bit rate.\n");
atom_offset=scan_aac_drilltoatom(fin,"mdat",&atom_length);
if ((atom_offset != -1) && (pmp3->song_length)) {
pmp3->bitrate = atom_length / ((pmp3->song_length / 1000) * 128);
}
}
fclose(fin);
return TRUE; /* we'll return as much as we got. */
}
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