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- Ripped some ID3 tag parsing from libid3 for typefind.

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Original commit message from CVS:
- Ripped some ID3 tag parsing from libid3 for typefind.
- Added ID3V1 to fypefind.
- Don't check for a valid mp3 header after finding the ID3 tag as some ID3
tags seem broken.
This commit is contained in:
Wim Taymans 2002-09-11 20:44:31 +00:00
parent a160852f16
commit 003d45f660
1 changed files with 42 additions and 25 deletions
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67
gst/mpegaudioparse/gstmp3types.c
View file

@ -31,36 +31,53 @@ static GstTypeDefinition mp3type_definitions[] = {
static GstCaps*
mp3_type_find(GstBuffer *buf, gpointer private)
{
gchar *data;
guint8 *data;
gint size;
gulong head;
GstCaps *caps;
data = GST_BUFFER_DATA(buf);
data = GST_BUFFER_DATA (buf);
size = GST_BUFFER_SIZE (buf);
GST_DEBUG (0,"mp3typefind: typefind");
/* check for ID3 Tag first and forward ID3 length */
if (!memcmp (data, "ID3", 3))
{
guint32 skip;
/* ignore next 3 bytes */
data += 6;
/* if you want that thing faster, do it */
skip = GUINT32_FROM_BE(*((guint32 *)data));
skip = (((skip & 0x7f000000) >> 3) |
((skip & 0x007f0000) >> 2) |
((skip & 0x00007f00) >> 1) |
((skip & 0x0000007f) >> 0)) + 4;
GST_DEBUG (0, "mp3typefind: detected ID3 Tag with %u bytes", skip + 6);
/* return if buffer is not big enough */
if (GST_BUFFER_SIZE (buf) < skip + 10)
{
GST_DEBUG (0, "mp3typefind: buffer too small (%d) to go on typefinding", skip + 6);
return NULL;
}
data += skip;
/* gracefully ripped from libid3 */
if (size >= 3 &&
data[0] == 'T' && data[1] == 'A' && data[2] == 'G') {
/* ID V1 tags */
data += 128;
GST_DEBUG (0, "mp3typefind: detected ID3 Tag V1");
}
else {
if (size >= 10 &&
(data[0] == 'I' && data[1] == 'D' && data[2] == '3') &&
data[3] < 0xff && data[4] < 0xff &&
data[6] < 0x80 && data[7] < 0x80 && data[8] < 0x80 && data[9] < 0x80)
{
guint32 skip = 0;
skip = (skip << 7) | (data[6] & 0x7f);
skip = (skip << 7) | (data[7] & 0x7f);
skip = (skip << 7) | (data[8] & 0x7f);
skip = (skip << 7) | (data[9] & 0x7f);
if (data[0] == 'I') {
/* ID3V2 */
/* footer present? */
if (data[5] & 0x10)
skip += 10;
skip += 10;
}
GST_DEBUG (0, "mp3typefind: detected ID3 Tag V2 with %u bytes", skip);
/* we currently accept a valid ID3 tag as an mp3 as some ID3 tags have invalid
* offsets so the next check might fail */
goto done;
}
}
/* now with the right postion, do typefinding */
head = GULONG_FROM_BE(*((gulong *)data));
if ((head & 0xffe00000) != 0xffe00000)
@ -74,8 +91,8 @@ mp3_type_find(GstBuffer *buf, gpointer private)
if (((head >> 10) & 0x3) == 0x3)
return NULL;
done:
caps = gst_caps_new ("mp3_type_find", "audio/mp3", NULL);
/* gst_caps_set(caps,"layer",GST_PROPS_INT(4-((head>>17)&0x3))); */
return caps;
}