/**
* 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
*/
uint64_t scan_aac_drilltoatom(IOHANDLE hfile,char *atom_path,
unsigned int *atom_length) {
uint64_t atom_offset;
uint64_t file_size,pos;
char *cur_p, *end_p;
char atom_name[5];
DPRINTF(E_SPAM,L_SCAN,"Searching for %s\n",atom_path);
// FIXME: cache io_size for static files
io_size(hfile, &file_size);
io_setpos(hfile,0,SEEK_SET);
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(hfile, file_size,
atom_name, atom_length);
if (atom_offset == -1) {
return -1;
}
io_getpos(hfile,&pos);
DPRINTF(E_SPAM,L_SCAN,"Found %s atom at off %lld.\n",
atom_name, pos - 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")) {
io_setpos(hfile, 4, SEEK_CUR);
} else if (!strcmp(atom_name, "stsd")) {
io_setpos(hfile, 8, SEEK_CUR);
} else if (!strcmp(atom_name, "mp4a")) {
io_setpos(hfile, 28, SEEK_CUR);
}
}
}
io_getpos(hfile, &pos);
return pos - 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
*/
int scan_aac_findatom(IOHANDLE hfile, uint64_t max_offset,
uint64_t *atom_offset, char *which_atom, unsigned int *atom_size) {
uint64_t current_offset=0;
uint32_t size;
char atom[4];
uint32_t bytes_read;
while((current_offset + 8) < max_offset) {
bytes_read = sizeof(uint32_t);
if(!io_read(hfile,(unsigned char *)&size,&bytes_read) || (!bytes_read)) {
return FALSE;
}
size=ntohl(size);
if(size <= 7) { /* something not right */
DPRINTF(E_LOG,L_SCAN,"Bad aac file: atom length too short searching for %s\n",
which_atom);
return FALSE;
}
bytes_read = 4;
if(!io_read(hfile,(unsigned char *)atom,&bytes_read) || (!bytes_read)) {
return FALSE;
}
if(strncasecmp(atom,which_atom,4) == 0) {
*atom_size=size;
*atom_offset = current_offset;
return TRUE;
}
io_setpos(hfile,size-8,SEEK_CUR);
current_offset+=size;
}
DPRINTF(E_SPAM,L_SCAN,"Couldn't find atom %s as requested\n",which_atom);
return FALSE;
}
/**
* 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) {
IOHANDLE hfile;
uint64_t atom_offset, pos;
uint32_t bytes_read;
unsigned int atom_length;
long current_offset=0;
uint32_t current_size;
char current_atom[4];
char *current_data;
unsigned short us_data;
int genre;
int len;
uint32_t sample_size;
uint32_t samples;
uint32_t bit_rate;
int ms;
unsigned char buffer[2];
uint32_t time = 0;
hfile = io_new();
if(!hfile)
DPRINTF(E_FATAL,L_SCAN,"Malloc error in scan_get_aacinfo\n");
if(!io_open(hfile,"file://%U",filename)) {
DPRINTF(E_INF,L_SCAN,"Cannot open file %s for reading: %s\n",filename,
io_errstr(hfile));
io_dispose(hfile);
return FALSE;
}
atom_offset=scan_aac_drilltoatom(hfile, "moov:udta:meta:ilst", &atom_length);
if(atom_offset != -1) {
/* found the tag section - need to walk through now */
while(current_offset < (uint64_t)atom_length) {
bytes_read = sizeof(uint32_t);
if(!io_read(hfile,(unsigned char *)¤t_size,&bytes_read) || !bytes_read) {
DPRINTF(E_LOG,L_SCAN,"Error reading mp4 atoms: %s\n",io_errstr(hfile));
io_dispose(hfile);
return FALSE;
}
current_size=ntohl(current_size);
DPRINTF(E_SPAM,L_SCAN,"Current size: %d\n",current_size);
if(current_size <= 7) { /* something not right */
DPRINTF(E_LOG,L_SCAN,"mp4 atom too small. Bad aac tags?\n");
io_dispose(hfile);
return FALSE;
}
bytes_read = 4;
if(!io_read(hfile,(unsigned char *)current_atom,&bytes_read) || !bytes_read) {
DPRINTF(E_LOG,L_SCAN,"Error reading mp4 atoms: %s\n",io_errstr(hfile));
io_dispose(hfile);
return FALSE;
}
DPRINTF(E_SPAM,L_SCAN,"Current Atom: %c%c%c%c\n",
current_atom[0],current_atom[1],current_atom[2],
current_atom[3]);
if(current_size > 4096) { /* Does this break anything? */
/* too big! cover art, maybe? */
io_setpos(hfile,current_size - 8, SEEK_CUR);
DPRINTF(E_SPAM,L_SCAN,"Atom too big... skipping\n");
} else {
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);
bytes_read = current_size - 8;
if(!io_read(hfile,(unsigned char *)current_data,&bytes_read) || (!bytes_read)) {
DPRINTF(E_LOG,L_SCAN,"Error reading mp4 data: %s\n",io_errstr(hfile));
free(current_data);
io_dispose(hfile);
return FALSE;
}
if(!memcmp(current_atom,"\xA9" "nam",4)) { /* Song name */
pmp3->title=strdup((char*)¤t_data[16]);
} else if(!memcmp(current_atom,"aART",4)) {
pmp3->album_artist=strdup((char*)¤t_data[16]);
} else if(!memcmp(current_atom,"\xA9" "ART",4)) {
pmp3->artist=strdup((char*)¤t_data[16]);
} else if(!memcmp(current_atom,"\xA9" "alb",4)) {
pmp3->album=strdup((char*)¤t_data[16]);
} else if(!memcmp(current_atom,"\xA9" "cmt",4)) {
pmp3->comment=strdup((char*)¤t_data[16]);
} else if(!memcmp(current_atom,"\xA9" "wrt",4)) {
pmp3->composer=strdup((char*)¤t_data[16]);
} else if(!memcmp(current_atom,"\xA9" "grp",4)) {
pmp3->grouping=strdup((char*)¤t_data[16]);
} else if(!memcmp(current_atom,"\xA9" "gen",4)) {
/* can this be a winamp genre??? */
pmp3->genre=strdup((char*)¤t_data[16]);
} else if(!memcmp(current_atom,"tmpo",4)) {
us_data=*((unsigned short *)¤t_data[16]);
us_data=ntohs(us_data);
pmp3->bpm=us_data;
} else if(!memcmp(current_atom,"trkn",4)) {
us_data=*((unsigned short *)¤t_data[18]);
us_data=ntohs(us_data);
pmp3->track=us_data;
us_data=*((unsigned short *)¤t_data[20]);
us_data=ntohs(us_data);
pmp3->total_tracks=us_data;
} else if(!memcmp(current_atom,"disk",4)) {
us_data=*((unsigned short *)¤t_data[18]);
us_data=ntohs(us_data);
pmp3->disc=us_data;
us_data=*((unsigned short *)¤t_data[20]);
us_data=ntohs(us_data);
pmp3->total_discs=us_data;
} else if(!memcmp(current_atom,"\xA9" "day",4)) {
pmp3->year=atoi((char*)¤t_data[16]);
} else if(!memcmp(current_atom,"gnre",4)) {
genre=(int)(*((char*)¤t_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(hfile, "moov:mvhd", &atom_length);
if(atom_offset != -1) {
io_setpos(hfile,4,SEEK_CUR);
/* FIXME: error handling */
bytes_read = sizeof(uint32_t);
if(!io_read(hfile,(unsigned char *)&time, &bytes_read)) {
DPRINTF(E_LOG,L_SCAN,"Error reading time from moov:mvhd: %s\n",
io_errstr(hfile));
io_dispose(hfile);
return FALSE;
}
time = ntohl(time);
pmp3->time_added = (int)scan_aac_mac_to_unix_time(time);
bytes_read = sizeof(uint32_t);
if(!io_read(hfile,(unsigned char *)&time, &bytes_read)) {
DPRINTF(E_LOG,L_SCAN,"Error reading time from moov:mvhd: %s\n",
io_errstr(hfile));
io_dispose(hfile);
return FALSE;
}
time = ntohl(time);
pmp3->time_modified = (int)scan_aac_mac_to_unix_time(time);
bytes_read = sizeof(uint32_t);
if(!io_read(hfile,(unsigned char *)&sample_size,&bytes_read)) {
DPRINTF(E_LOG,L_SCAN,"Error reading sample_size from moov:mvhd: %s\n",
io_errstr(hfile));
io_dispose(hfile);
return FALSE;
}
bytes_read = sizeof(uint32_t);
if(!io_read(hfile,(unsigned char*)&samples, &bytes_read)) {
DPRINTF(E_LOG,L_SCAN,"Error reading samples from moov:mvhd: %s\n",
io_errstr(hfile));
io_dispose(hfile);
return FALSE;
}
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=(uint32_t)((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(hfile,
"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(hfile,
"moov:trak:mdia:minf:stbl:stsd:mp4a",
&atom_length);
if(atom_offset == -1) {
atom_offset=scan_aac_drilltoatom(hfile,
"moov:trak:mdia:minf:stbl:stsd:drms",
&atom_length);
}
if (atom_offset != -1) {
io_setpos(hfile, 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. */
bytes_read = 2;
if(!io_read(hfile, (unsigned char *)buffer, &bytes_read)) {
DPRINTF(E_LOG,L_SCAN,"Error reading timescale from drms atom: %s\n",
io_errstr(hfile));
io_dispose(hfile);
return FALSE;
}
pmp3->samplerate = (buffer[0] << 8) | (buffer[1]);
/* Seek to end of atom. */
io_setpos(hfile, 2, SEEK_CUR);
/* Get the bit rate from the 'esds' atom. We are already positioned
in the parent atom so just scan ahead. */
io_getpos(hfile,&pos);
atom_offset = scan_aac_findatom(hfile,
atom_length-(pos-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.
*/
io_setpos(hfile, atom_offset + 22, SEEK_CUR);
bytes_read = sizeof(unsigned int);
if(!io_read(hfile, (unsigned char *)&bit_rate, &bytes_read)) {
DPRINTF(E_LOG,L_SCAN,"Error reading bitrate from esds: %s\n",
io_errstr(hfile));
io_dispose(hfile);
return FALSE;
}
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(hfile,"mdat",&atom_length);
if ((atom_offset != -1) && (pmp3->song_length >= 1000)) {
pmp3->bitrate = atom_length / ((pmp3->song_length / 1000) * 128);
}
}
io_close(hfile);
io_dispose(hfile);
return TRUE; /* we'll return as much as we got. */
}
