mirrors/gstreamer
mirrors/gstreamer
1
1
Fork 0
mirror of https://gitlab.freedesktop.org/gstreamer/gstreamer.git synced 2024-12-24 01:00:37 +00:00
Code Issues 1 Projects Releases Wiki Activity

gst/typefind/gsttypefindfunctions.c: Improve FLAC-without-headers typefinding by looking at most of the frame header ...

Browse source 
Original commit message from CVS:
* gst/typefind/gsttypefindfunctions.c: (flac_type_find):
Improve FLAC-without-headers typefinding by looking at most of the
frame header and checking if invalid values are used. Should prevent
quite some false positives compared to the old version which only
check if the first 14 bits are set.
This commit is contained in:
Sebastian Dröge 2008-10-13 07:52:41 +00:00
parent 13759bcbff
commit 862fd1d50f
2 changed files with 33 additions and 3 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

8
ChangeLog
View file

@ -1,3 +1,11 @@
2008-10-13 Sebastian Dröge <sebastian.droege@collabora.co.uk>
* gst/typefind/gsttypefindfunctions.c: (flac_type_find):
Improve FLAC-without-headers typefinding by looking at most of the
frame header and checking if invalid values are used. Should prevent
quite some false positives compared to the old version which only
check if the first 14 bits are set.
2008-10-11 Stefan Kost <ensonic@users.sf.net>
* sys/xvimage/xvimagesink.c:

28
gst/typefind/gsttypefindfunctions.c
View file

@ -541,13 +541,35 @@ flac_type_find (GstTypeFind * tf, gpointer unused)
/* flac without headers */
/* 64K should be enough */
while (c.offset < (64 * 1024)) {
if (G_UNLIKELY (!data_scan_ctx_ensure_data (tf, &c, 2)))
if (G_UNLIKELY (!data_scan_ctx_ensure_data (tf, &c, 3)))
break;
if (data[0] == 0xff && (data[1] >> 2) == 0x3e) {
/* bit 15 must be 0 */
if (((data[1] >> 1) & 0x01) == 0x01)
continue;
/* blocksize must be != 0x00 */
if ((data[2] >> 4) == 0x00)
continue;
/* samplerate must be != 0x0f */
if ((data[2] & 0x0f) == 0x0f)
continue;
/* channel assignment must be < 11 */
if ((data[3] >> 4) >= 11)
continue;
/* sample size must be != 0x07 */
if (((data[3] >> 1) & 0x07) == 0x07)
continue;
/* next bit must be 0 */
if ((data[3] & 0x01) == 0x01)
continue;
gst_type_find_suggest (tf, GST_TYPE_FIND_LIKELY, FLAC_CAPS);
/* TODO: maybe check more parts of the frame header
* to lower the risk of false positives */
return;
}
data_scan_ctx_advance (tf, &c, 1);