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rockbox/firmware/id3.c
Linus Nielsen Feltzing fd3d50a4db Better handling of large frames in V2 tags 
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@2771 a1c6a512-1295-4272-9138-f99709370657
2002-10-29 10:29:57 +00:00

802 lines
21 KiB
C
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/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2002 by Daniel Stenberg
*
* All files in this archive are subject to the GNU General Public License.
* See the file COPYING in the source tree root for full license agreement.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
/*
* Parts of this code has been stolen from the Ample project and was written
* by David Härdeman. It has since been extended and enhanced pretty much by
* all sorts of friendly Rockbox people.
*
* A nice reference for MPEG header info:
* http://rockbox.haxx.se/docs/mpeghdr.html
*
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <stdbool.h>
#include "file.h"
#include "debug.h"
#include "atoi.h"
#include "id3.h"
#define UNSYNC(b0,b1,b2,b3) (((b0 & 0x7F) << (3*7)) | \
((b1 & 0x7F) << (2*7)) | \
((b2 & 0x7F) << (1*7)) | \
((b3 & 0x7F) << (0*7)))
#define BYTES2INT(b0,b1,b2,b3) (((b0 & 0xFF) << (3*8)) | \
((b1 & 0xFF) << (2*8)) | \
((b2 & 0xFF) << (1*8)) | \
((b3 & 0xFF) << (0*8)))
/* Table of bitrates for MP3 files, all values in kilo.
* Indexed by version, layer and value of bit 15-12 in header.
*/
const int bitrate_table[2][3][16] =
{
{
{0,32,64,96,128,160,192,224,256,288,320,352,384,416,448,0},
{0,32,48,56, 64,80, 96, 112,128,160,192,224,256,320,384,0},
{0,32,40,48, 56,64, 80, 96, 112,128,160,192,224,256,320,0}
},
{
{0,32,48,56,64,80,96,112,128,144,160,176,192,224,256,0},
{0, 8,16,24,32,40,48, 56, 64, 80, 96,112,128,144,160,0},
{0, 8,16,24,32,40,48, 56, 64, 80, 96,112,128,144,160,0}
}
};
/* Table of samples per frame for MP3 files.
* Indexed by layer. Multiplied with 1000.
*/
const int bs[4] = {0, 384000, 1152000, 1152000};
/* Table of sample frequency for MP3 files.
* Indexed by version and layer.
*/
const int freqtab[][4] =
{
{11025, 12000, 8000, 0}, /* MPEG version 2.5 */
{44100, 48000, 32000, 0}, /* MPEG Version 1 */
{22050, 24000, 16000, 0}, /* MPEG version 2 */
};
#define UNICODE_BOM_1 0xfffe
#define UNICODE_BOM_2 0xfeff
/* Checks to see if the passed in string is a 16-bit wide Unicode v2
string. If it is, we attempt to convert it to a 8-bit ASCII string
(for valid 8-bit ASCII characters). If it's not unicode, we leave
it alone. At some point we should fully support unicode strings */
static int unicode_munge(char** string, int *len) {
int tmp;
bool le = false;
int i;
char *str = *string;
char *outstr = *string;
if(str[0] > 0x03) {
/* Plain old string */
return 0;
}
/* Type 0x00 is ordinary ISO 8859-1 */
if(str[0] == 0x00) {
(*len)--;
(*string)++; /* Skip the encoding type byte */
return 0;
}
/* Unicode with or without BOM */
if(str[0] == 0x01 || str[0] == 0x02) {
str++;
tmp = BYTES2INT(0, 0, str[1], str[2]);
if(tmp == UNICODE_BOM_2) { /* Little endian? */
le = true;
str += 2;
}
if(tmp == UNICODE_BOM_1) /* Big endian? */
str += 2;
i = 0;
do {
if(le) {
if(str[1])
outstr[i++] = '.';
else
outstr[i++] = str[0];
} else {
if(str[0])
outstr[i++] = '.';
else
outstr[i++] = str[1];
}
} while(str[0] || str[1]);
*len = i;
(*string)++; /* Skip the encoding type byte */
return 0;
}
/* If we come here, the string was of an unsupported type */
*len = 1;
outstr[0] = 0;
return -1;
}
/*
* Removes trailing spaces from a string.
*
* Arguments: buffer - the string to process
*
* Returns: void
*/
static void
stripspaces(char *buffer)
{
int i = 0;
while(*(buffer + i) != '\0')
i++;
for(;i >= 0; i--) {
if(*(buffer + i) == ' ')
*(buffer + i) = '\0';
else if(*(buffer + i) == '\0')
continue;
else
break;
}
}
/*
* Sets the title of an MP3 entry based on its ID3v1 tag.
*
* Arguments: file - the MP3 file to scen for a ID3v1 tag
* entry - the entry to set the title in
*
* Returns: true if a title was found and created, else false
*/
static bool setid3v1title(int fd, struct mp3entry *entry)
{
unsigned char buffer[31];
int offsets[4] = {-95,-65,-125,-31};
int i;
for (i=0;i<4;i++) {
if (-1 == lseek(fd, offsets[i], SEEK_END))
return false;
buffer[30]=0;
read(fd, buffer, 30);
stripspaces(buffer);
if (buffer[0] || i == 3) {
switch(i) {
case 0:
strcpy(entry->id3v1buf[0], buffer);
entry->artist = entry->id3v1buf[0];
break;
case 1:
strcpy(entry->id3v1buf[1], buffer);
entry->album = entry->id3v1buf[1];
break;
case 2:
strcpy(entry->id3v1buf[2], buffer);
entry->title = entry->id3v1buf[2];
break;
case 3:
/* id3v1.1 uses last two bytes of comment field for track
number: first must be 0 and second is track num */
if (buffer[28] == 0)
entry->tracknum = buffer[29];
break;
}
}
}
return true;
}
/*
* Sets the title of an MP3 entry based on its ID3v2 tag.
*
* Arguments: file - the MP3 file to scan for a ID3v2 tag
* entry - the entry to set the title in
*
* Returns: true if a title was found and created, else false
*/
static void setid3v2title(int fd, struct mp3entry *entry)
{
int minframesize;
int size;
int bufferpos = 0, totframelen, framelen;
char header[10];
unsigned short int version;
char *buffer = entry->id3v2buf;
char *tracknum = NULL;
int bytesread = 0;
int buffersize = sizeof(entry->id3v2buf);
/* Bail out if the tag is shorter than 10 bytes */
if(entry->id3v2len < 10)
return;
/* Read the ID3 tag version from the header */
lseek(fd, 0, SEEK_SET);
if(10 != read(fd, header, 10))
return;
version = (unsigned short int)header[3];
/* Get the total ID3 tag size */
size = entry->id3v2len - 10;
/* Set minimum frame size according to ID3v2 version */
if(version > 2)
minframesize = 12;
else
minframesize = 8;
/*
* We must have at least minframesize bytes left for the
* remaining frames to be interesting
*/
while(size > minframesize) {
/* Read frame header and check length */
if(version > 2) {
if(10 != read(fd, header, 10))
return;
/* Adjust for the 10 bytes we read */
size -= 10;
if (version > 3) {
framelen = UNSYNC(header[4], header[5],
header[6], header[7]);
} else {
/* version .3 files don't use synchsafe ints for
* size */
framelen = BYTES2INT(header[4], header[5],
header[6], header[7]);
}
} else {
if(6 != read(fd, header, 6))
return;
/* Adjust for the 6 bytes we read */
size -= 6;
framelen = BYTES2INT(0, header[3], header[4], header[5]);
}
/* Keep track of the total size */
totframelen = framelen;
if(framelen == 0)
return;
/* If the frame is larger than the remaining buffer space we try
to read as much as would fit in the buffer */
if(framelen >= buffersize - bufferpos)
framelen = buffersize - bufferpos - 1;
/* Check for certain frame headers */
if(!strncmp(header, "TPE1", strlen("TPE1")) ||
!strncmp(header, "TP1", strlen("TP1"))) {
bytesread = read(fd, buffer + bufferpos, framelen);
entry->artist = buffer + bufferpos;
unicode_munge(&entry->artist, &bytesread);
entry->artist[bytesread + 1] = '\0';
bufferpos += bytesread + 2;
size -= bytesread;
}
else if(!strncmp(header, "TIT2", strlen("TIT2")) ||
!strncmp(header, "TT2", strlen("TT2"))) {
bytesread = read(fd, buffer + bufferpos, framelen);
entry->title = buffer + bufferpos;
unicode_munge(&entry->title, &bytesread);
entry->title[bytesread + 1] = '\0';
bufferpos += bytesread + 2;
size -= bytesread;
}
else if(!strncmp(header, "TALB", strlen("TALB"))) {
bytesread = read(fd, buffer + bufferpos, framelen);
entry->album = buffer + bufferpos;
unicode_munge(&entry->album, &bytesread);
entry->album[bytesread + 1] = '\0';
bufferpos += bytesread + 2;
size -= bytesread;
}
else if(!strncmp(header, "TRCK", strlen("TRCK"))) {
bytesread = read(fd, buffer + bufferpos, framelen);
tracknum = buffer + bufferpos;
unicode_munge(&tracknum, &bytesread);
tracknum[bytesread + 1] = '\0';
entry->tracknum = atoi(tracknum);
bufferpos += bytesread + 1;
size -= bytesread;
}
else {
/* Unknown frame, skip it using the total size in case
it was truncated */
size -= totframelen;
lseek(fd, totframelen, SEEK_CUR);
}
}
}
/*
* Calculates the size of the ID3v2 tag.
*
* Arguments: file - the file to search for a tag.
*
* Returns: the size of the tag or 0 if none was found
*/
static int getid3v2len(int fd)
{
char buf[6];
int offset;
/* Make sure file has a ID3 tag */
if((-1 == lseek(fd, 0, SEEK_SET)) ||
(read(fd, buf, 6) != 6) ||
(strncmp(buf, "ID3", strlen("ID3")) != 0))
offset = 0;
/* Now check what the ID3v2 size field says */
else if(read(fd, buf, 4) != 4)
offset = 0;
else
offset = UNSYNC(buf[0], buf[1], buf[2], buf[3]) + 10;
return offset;
}
static int getfilesize(int fd)
{
int size;
/* seek to the end of it */
size = lseek(fd, 0, SEEK_END);
if(-1 == size)
return 0; /* unknown */
return size;
}
/*
* Calculates the size of the ID3v1 tag.
*
* Arguments: file - the file to search for a tag.
*
* Returns: the size of the tag or 0 if none was found
*/
static int getid3v1len(int fd)
{
char buf[3];
int offset;
/* Check if we find "TAG" 128 bytes from EOF */
if((lseek(fd, -128, SEEK_END) == -1) ||
(read(fd, buf, 3) != 3) ||
(strncmp(buf, "TAG", 3) != 0))
offset = 0;
else
offset = 128;
return offset;
}
/* check if 'head' is a valid mp3 frame header */
static bool mp3frameheader(unsigned long head)
{
if ((head & 0xffe00000) != 0xffe00000) /* bad sync? */
return false;
if (!((head >> 17) & 3)) /* no layer? */
return false;
if (((head >> 12) & 0xf) == 0xf) /* bad bitrate? */
return false;
if (!((head >> 12) & 0xf)) /* no bitrate? */
return false;
if (((head >> 10) & 0x3) == 0x3) /* bad sample rate? */
return false;
if (((head >> 19) & 1) == 1 &&
((head >> 17) & 3) == 3 &&
((head >> 16) & 1) == 1)
return false;
if ((head & 0xffff0000) == 0xfffe0000)
return false;
return true;
}
/*
* Calculates the length (in milliseconds) of an MP3 file.
*
* Modified to only use integers.
*
* Arguments: file - the file to calculate the length upon
* entry - the entry to update with the length
*
* Returns: the song length in milliseconds,
* 0 means that it couldn't be calculated
*/
static int getsonglength(int fd, struct mp3entry *entry)
{
unsigned int filetime = 0;
unsigned long header=0;
unsigned char tmp;
unsigned char frame[156];
unsigned char* xing;
enum {
MPEG_VERSION2_5,
MPEG_VERSION1,
MPEG_VERSION2
} version;
int layer;
int bitindex;
int bitrate;
int freqindex;
int frequency;
int chmode;
int bytecount;
int bytelimit;
int bittable; /* which bitrate table to use */
bool header_found = false;
long bpf;
long tpf;
/* Start searching after ID3v2 header */
if(-1 == lseek(fd, entry->id3v2len, SEEK_SET))
return 0;
/* Fill up header with first 24 bits */
for(version = 0; version < 3; version++) {
header <<= 8;
if(!read(fd, &tmp, 1))
return 0;
header |= tmp;
}
/* Loop trough file until we find a frame header */
bytecount = entry->id3v2len - 1;
bytelimit = entry->id3v2len + 0x20000;
restart:
do {
header <<= 8;
if(!read(fd, &tmp, 1))
return 0;
header |= tmp;
/* Quit if we haven't found a valid header within 128K */
bytecount++;
if(bytecount > bytelimit)
return 0;
} while(!mp3frameheader(header));
/*
* Some files are filled with garbage in the beginning,
* if the bitrate index of the header is binary 1111
* that is a good indicator
*/
if((header & 0xF000) == 0xF000)
goto restart;
/* MPEG Audio Version */
switch((header & 0x180000) >> 19) {
case 0:
/* MPEG version 2.5 is not an official standard */
version = MPEG_VERSION2_5;
bittable = MPEG_VERSION2; /* use the V2 bit rate table */
break;
case 2:
/* MPEG version 2 (ISO/IEC 13818-3) */
version = MPEG_VERSION2;
bittable = MPEG_VERSION2;
break;
case 3:
/* MPEG version 1 (ISO/IEC 11172-3) */
version = MPEG_VERSION1;
bittable = MPEG_VERSION1;
break;
default:
goto restart;
}
/* Layer */
switch((header & 0x060000) >> 17) {
case 1:
layer = 3;
break;
case 2:
layer = 2;
break;
case 3:
layer = 1;
break;
default:
goto restart;
}
/* Bitrate */
bitindex = (header & 0xF000) >> 12;
bitrate = bitrate_table[bittable-1][layer-1][bitindex];
if(bitrate == 0)
goto restart;
/* Sampling frequency */
freqindex = (header & 0x0C00) >> 10;
frequency = freqtab[version][freqindex];
if(frequency == 0)
goto restart;
#ifdef DEBUG_VERBOSE
DEBUGF( "Version %i, lay %i, biti %i, bitr %i, freqi %i, freq %i, chmode %d\n",
version, layer, bitindex, bitrate, freqindex, frequency, chmode);
#endif
entry->version = version;
entry->layer = layer;
entry->frequency = frequency;
/* Calculate bytes per frame, calculation depends on layer */
switch(layer) {
case 1:
bpf = bitrate_table[bittable - 1][layer - 1][bitindex];
bpf *= 48000;
bpf /= freqtab[version][freqindex] << (bittable - 1);
break;
case 2:
case 3:
bpf = bitrate_table[bittable - 1][layer - 1][bitindex];
bpf *= 144000;
bpf /= freqtab[version][freqindex] << (bittable - 1);
break;
default:
bpf = 1;
}
/* Calculate time per frame */
tpf = bs[layer] / (freqtab[version][freqindex] << (bittable - 1));
entry->bpf = bpf;
entry->tpf = tpf;
/* OK, we have found a frame. Let's see if it has a Xing header */
if(read(fd, frame, sizeof frame) < 0)
return -1;
/* Channel mode (stereo/mono) */
chmode = (header & 0xc0) >> 6;
/* calculate position of Xing VBR header */
if ( version == 1 ) {
if ( chmode == 3 ) /* mono */
xing = frame + 17;
else
xing = frame + 32;
}
else {
if ( chmode == 3 ) /* mono */
xing = frame + 9;
else
xing = frame + 17;
}
if (xing[0] == 'X' &&
xing[1] == 'i' &&
xing[2] == 'n' &&
xing[3] == 'g')
{
int i = 8; /* Where to start parsing info */
/* Yes, it is a VBR file */
entry->vbr = true;
entry->vbrflags = xing[7];
if (entry->vbrflags & VBR_FRAMES_FLAG) /* Is the frame count there? */
{
int framecount = (xing[i] << 24) | (xing[i+1] << 16) |
(xing[i+2] << 8) | xing[i+3];
filetime = framecount * tpf;
i += 4;
}
if (entry->vbrflags & VBR_BYTES_FLAG) /* is byte count there? */
{
int bytecount = (xing[i] << 24) | (xing[i+1] << 16) |
(xing[i+2] << 8) | xing[i+3];
bitrate = bytecount * 8 / filetime;
i += 4;
}
if (entry->vbrflags & VBR_TOC_FLAG) /* is table-of-contents there? */
{
memcpy( entry->toc, xing+i, 100 );
}
/* Make sure we skip this frame in playback */
bytecount += bpf;
header_found = true;
}
if (xing[0] == 'V' &&
xing[1] == 'B' &&
xing[2] == 'R' &&
xing[3] == 'I')
{
int framecount;
int bytecount;
/* Yes, it is a FhG VBR file */
entry->vbr = true;
entry->vbrflags = 0;
bytecount = (xing[10] << 24) | (xing[11] << 16) |
(xing[12] << 8) | xing[13];
framecount = (xing[14] << 24) | (xing[15] << 16) |
(xing[16] << 8) | xing[17];
filetime = framecount * tpf;
bitrate = bytecount * 8 / filetime;
/* We don't parse the TOC, since we don't yet know how to (FIXME) */
/* Make sure we skip this frame in playback */
bytecount += bpf;
header_found = true;
}
/* Is it a LAME Info frame? */
if (xing[0] == 'I' &&
xing[1] == 'n' &&
xing[2] == 'f' &&
xing[3] == 'o')
{
/* Make sure we skip this frame in playback */
bytecount += bpf;
header_found = true;
}
entry->bitrate = bitrate;
/* If the file time hasn't been established, this may be a fixed
rate MP3, so just use the default formula */
if(filetime == 0)
{
/*
* Now song length is
* ((filesize)/(bytes per frame))*(time per frame)
*/
filetime = entry->filesize/bpf*tpf;
}
/* Update the seek point for the first playable frame */
entry->first_frame_offset = bytecount;
DEBUGF("First frame is at %x\n", entry->first_frame_offset);
return filetime;
}
/*
* Checks all relevant information (such as ID3v1 tag, ID3v2 tag, length etc)
* about an MP3 file and updates it's entry accordingly.
*
* Arguments: entry - the entry to check and update with the new information
*
* Returns: void
*/
bool mp3info(struct mp3entry *entry, char *filename)
{
int fd;
fd = open(filename, O_RDONLY);
if(-1 == fd)
return true;
memset(entry, 0, sizeof(struct mp3entry));
strncpy(entry->path, filename, sizeof(entry->path));
entry->title = NULL;
entry->filesize = getfilesize(fd);
entry->id3v2len = getid3v2len(fd);
entry->tracknum = 0;
if (entry->id3v2len)
setid3v2title(fd, entry);
entry->length = getsonglength(fd, entry);
entry->id3v1len = getid3v1len(fd);
if(entry->id3v1len && !entry->title)
setid3v1title(fd, entry);
close(fd);
if(!entry->length || (entry->filesize < 8 ))
/* no song length or less than 8 bytes is hereby considered to be an
invalid mp3 and won't be played by us! */
return true;
return false;
}
#ifdef DEBUG_STANDALONE
char *secs2str(int ms)
{
static char buffer[32];
int secs = ms/1000;
ms %= 1000;
snprintf(buffer, sizeof(buffer), "%d:%02d.%d", secs/60, secs%60, ms/100);
return buffer;
}
int main(int argc, char **argv)
{
int i;
for(i=1; i<argc; i++) {
struct mp3entry mp3;
if(mp3info(&mp3, argv[i])) {
printf("Failed to get %s\n", argv[i]);
return 0;
}
printf("****** File: %s\n"
" Title: %s\n"
" Artist: %s\n"
" Album: %s\n"
" Length: %s / %d s\n"
" Bitrate: %d\n"
" Frequency: %d\n",
argv[i],
mp3.title?mp3.title:"<blank>",
mp3.artist?mp3.artist:"<blank>",
mp3.album?mp3.album:"<blank>",
secs2str(mp3.length),
mp3.length/1000,
mp3.bitrate,
mp3.frequency);
}
return 0;
}
#endif
/* -----------------------------------------------------------------
* local variables:
* eval: (load-file "rockbox-mode.el")
* end:
*/
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