FaSTTUBe/GST-Tensordecoder-ov_ep
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typefindfunctions: Consider the number and types of atoms found in a row for suggesting a probability

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If there are 3 or more known atoms in a row, it's likely that this is
actually MOV/MP4 even if we don't find any other known atoms. If 5 or
more are found then this is most certainly MOV/MP4 and we can return.

Also if a moov and mdat atom is found, this is definitely a MOV/MP4 file
and can be used as such, independent of anything else following the
mdat.

Fixes typefinding of various MOV files that have no `ftyp` atom but
otherwise a valid file structure followed by some garbage.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-base/-/merge_requests/1013>
This commit is contained in:
Sebastian Dröge 2021-01-19 10:23:12 +02:00
parent 9ab400e267
commit 23370ec429
1 changed files with 17 additions and 1 deletions
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16
gst/typefind/gsttypefindfunctions.c
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@ -3383,6 +3383,8 @@ qt_type_find (GstTypeFind * tf, gpointer unused)
{ {
const guint8 *data; const guint8 *data;
guint tip = 0; guint tip = 0;
guint atoms_in_a_row = 0;
gboolean have_moov = FALSE, have_mdat = FALSE;
guint64 offset = 0; guint64 offset = 0;
guint64 size; guint64 size;
const gchar *variant = NULL; const gchar *variant = NULL;
@ -3435,6 +3437,17 @@ qt_type_find (GstTypeFind * tf, gpointer unused)
} else { } else {
tip = GST_TYPE_FIND_NEARLY_CERTAIN; tip = GST_TYPE_FIND_NEARLY_CERTAIN;
} }
if (STRNCMP (&data[4], "moov", 4) == 0)
have_moov = TRUE;
if (STRNCMP (&data[4], "mdat", 4) == 0)
have_mdat = TRUE;
atoms_in_a_row += 1;
if ((have_moov && have_mdat) || atoms_in_a_row >= 5) {
tip = GST_TYPE_FIND_MAXIMUM;
break;
}
} }
/* other box/atom types, apparently quicktime specific */ /* other box/atom types, apparently quicktime specific */
else if (STRNCMP (&data[4], "pnot", 4) == 0 || else if (STRNCMP (&data[4], "pnot", 4) == 0 ||
@ -3444,6 +3457,9 @@ qt_type_find (GstTypeFind * tf, gpointer unused)
tip = GST_TYPE_FIND_MAXIMUM; tip = GST_TYPE_FIND_MAXIMUM;
break; break;
} else { } else {
if (atoms_in_a_row >= 3)
tip = GST_TYPE_FIND_LIKELY;
else
tip = 0; tip = 0;
break; break;
} }