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id3v2 reader

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patch by Andreas Öman andreas olebyn nu
original thread: [FFmpeg-devel] [Ffmpeg-devel] ID3v2

Originally committed as revision 9101 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Andreas Öman 2007-05-22 08:23:45 +00:00 committed by Benoit Fouet
parent cb2578d5ef
commit 52b53f8653
1 changed files with 145 additions and 2 deletions
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147
libavformat/mp3.c
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@ -169,6 +169,149 @@ static int id3v2_match(const uint8_t *buf)
(buf[9] & 0x80) == 0);
}
static unsigned int id3v2_get_size(ByteIOContext *s, int len)
{
int v=0;
while(len--)
v= (v<<7) + (get_byte(s)&0x7F);
return v;
}
static void id3v2_read_ttag(AVFormatContext *s, int taglen, char *dst, int dstlen)
{
char *q;
int len;
if(taglen < 1)
return;
taglen--; /* account for encoding type byte */
dstlen--; /* Leave space for zero terminator */
switch(get_byte(&s->pb)) { /* encoding type */
case 0: /* ISO-8859-1 (0 - 255 maps directly into unicode) */
q = dst;
while(taglen--) {
uint8_t tmp;
PUT_UTF8(get_byte(&s->pb), tmp, if (q - dst < dstlen - 1) *q++ = tmp;)
}
*q = '\0';
break;
case 3: /* UTF-8 */
len = FFMIN(taglen, dstlen);
get_buffer(&s->pb, dst, len);
dst[len] = 0;
break;
}
}
/**
* ID3v2 parser
*
* Handles ID3v2.2, 2.3 and 2.4.
*
*/
static void id3v2_parse(AVFormatContext *s, int len, uint8_t version, uint8_t flags)
{
int isv34, tlen;
uint32_t tag;
offset_t next;
char tmp[16];
int taghdrlen;
const char *reason;
switch(version) {
case 2:
if(flags & 0x40) {
reason = "compression";
goto error;
}
isv34 = 0;
taghdrlen = 6;
break;
case 3 ... 4:
isv34 = 1;
taghdrlen = 10;
break;
default:
reason = "version";
goto error;
}
if(flags & 0x80) {
reason = "unsynchronization";
goto error;
}
if(isv34 && flags & 0x40) /* Extended header present, just skip over it */
url_fskip(&s->pb, id3v2_get_size(&s->pb, 4));
while(len >= taghdrlen) {
if(isv34) {
tag = get_be32(&s->pb);
tlen = id3v2_get_size(&s->pb, 4);
get_be16(&s->pb); /* flags */
} else {
tag = get_be24(&s->pb);
tlen = id3v2_get_size(&s->pb, 3);
}
len -= taghdrlen + tlen;
if(len < 0)
break;
next = url_ftell(&s->pb) + tlen;
switch(tag) {
case MKBETAG('T', 'I', 'T', '2'):
case MKBETAG(0, 'T', 'T', '2'):
id3v2_read_ttag(s, tlen, s->title, sizeof(s->title));
break;
case MKBETAG('T', 'P', 'E', '1'):
case MKBETAG(0, 'T', 'P', '1'):
id3v2_read_ttag(s, tlen, s->author, sizeof(s->author));
break;
case MKBETAG('T', 'A', 'L', 'B'):
case MKBETAG(0, 'T', 'A', 'L'):
id3v2_read_ttag(s, tlen, s->album, sizeof(s->album));
break;
case MKBETAG('T', 'C', 'O', 'N'):
case MKBETAG(0, 'T', 'C', 'O'):
id3v2_read_ttag(s, tlen, s->genre, sizeof(s->genre));
break;
case MKBETAG('T', 'C', 'O', 'P'):
case MKBETAG(0, 'T', 'C', 'R'):
id3v2_read_ttag(s, tlen, s->copyright, sizeof(s->copyright));
break;
case MKBETAG('T', 'R', 'C', 'K'):
case MKBETAG(0, 'T', 'R', 'K'):
id3v2_read_ttag(s, tlen, tmp, sizeof(tmp));
s->track = atoi(tmp);
break;
case 0:
/* padding, skip to end */
url_fskip(&s->pb, len);
len = 0;
continue;
}
/* Skip to end of tag */
url_fseek(&s->pb, next, SEEK_SET);
}
if(version == 4 && flags & 0x10) /* Footer preset, always 10 bytes, skip over it */
url_fskip(&s->pb, 10);
return;
error:
av_log(s, AV_LOG_INFO, "ID3v2.%d tag skipped, cannot handle %s\n", version, reason);
url_fskip(&s->pb, len);
}
static void id3v1_get_string(char *str, int str_size,
const uint8_t *buf, int buf_size)
{
@ -313,12 +456,12 @@ static int mp3_read_header(AVFormatContext *s,
if (ret != ID3v2_HEADER_SIZE)
return -1;
if (id3v2_match(buf)) {
/* skip ID3v2 header */
/* parse ID3v2 header */
len = ((buf[6] & 0x7f) << 21) |
((buf[7] & 0x7f) << 14) |
((buf[8] & 0x7f) << 7) |
(buf[9] & 0x7f);
url_fskip(&s->pb, len);
id3v2_parse(s, len, buf[3], buf[5]);
} else {
url_fseek(&s->pb, 0, SEEK_SET);
}