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gst/typefind/gsttypefindfunctions.c: Improve MXF typefinding a bit by searching for a header partition pack instead o...

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Original commit message from CVS:
* gst/typefind/gsttypefindfunctions.c: (mxf_type_find):
Improve MXF typefinding a bit by searching for a header partition
pack instead of just a general partition pack and checking more
bytes for valid values.
This commit is contained in:
Sebastian Dröge 2008-10-20 14:08:52 +00:00
parent 4c2f85f96c
commit e4e86b0bad
2 changed files with 30 additions and 10 deletions
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7
ChangeLog
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@ -1,3 +1,10 @@
2008-10-20 Sebastian Dröge <sebastian.droege@collabora.co.uk>
* gst/typefind/gsttypefindfunctions.c: (mxf_type_find):
Improve MXF typefinding a bit by searching for a header partition
pack instead of just a general partition pack and checking more
bytes for valid values.
2008-10-20 Wim Taymans <wim.taymans@collabora.co.uk>
* tests/icles/.cvsignore:

33
gst/typefind/gsttypefindfunctions.c
View file

@ -2375,28 +2375,41 @@ static GstStaticCaps mxf_caps = GST_STATIC_CAPS ("application/mxf");
#define MXF_CAPS (gst_static_caps_get(&mxf_caps))
/*
* Quoting http://www.digitalpreservation.gov/formats/fdd/fdd000013.shtml:
* "MXF files start with an optional run-in followed by the SMPTE header partition pack key.
* The run-in is less than 64k bytes and the condition for finding the start of the file is
* to identify the first 11 bytes of the partition pack key . . . scan the initial 64 k bytes
* for these 11 bytes" to identify an MXF file. (From SMPTE EG 41, p. 45) The 11 bytes listed
* are from SMPTE 377M, p.20.
* MXF files start with a header partition pack key of 16 bytes which is defined
* at SMPTE-377M 6.1. Before this there can be up to 64K of run-in which _must_
* not contain the partition pack key.
*/
static void
mxf_type_find (GstTypeFind * tf, gpointer ununsed)
{
static const guint8 header_partition_pack_key[] =
{ 0x06, 0x0e, 0x2b, 0x34, 0x02, 0x05, 0x01, 0x01, 0x0d, 0x01, 0x02 };
static const guint8 partition_pack_key[] =
{ 0x06, 0x0e, 0x2b, 0x34, 0x02, 0x05, 0x01, 0x01, 0x0d, 0x01, 0x02, 0x01,
0x01
};
DataScanCtx c = { 0, NULL, 0 };
while (c.offset <= MXF_MAX_PROBE_LENGTH) {
if (G_UNLIKELY (!data_scan_ctx_ensure_data (tf, &c, 11)))
if (G_UNLIKELY (!data_scan_ctx_ensure_data (tf, &c, 16)))
break;
if (memcmp (c.data, header_partition_pack_key, 11) == 0) {
if (memcmp (c.data, partition_pack_key, 13) == 0) {
/* Header partition pack? */
if (c.data[13] != 0x02)
goto advance;
/* Partition status */
if (c.data[14] >= 0x05)
goto advance;
/* Reserved, must be 0x00 */
if (c.data[15] != 0x00)
goto advance;
gst_type_find_suggest (tf, GST_TYPE_FIND_MAXIMUM, MXF_CAPS);
return;
}
advance:
data_scan_ctx_advance (tf, &c, 1);
}
}