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gst/typefind/gsttypefindfunctions.c: Don't do lots of 4-byte peeks, but use the 'new' data scan helper for this inste...

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Original commit message from CVS:
* gst/typefind/gsttypefindfunctions.c: (h264_video_type_find):
Don't do lots of 4-byte peeks, but use the 'new' data scan helper
for this instead; don't check if we've found enough markers after
each and every step, it's enough to do that only if we've actually
found a new marker.
Embed a G_UNLIKELY into the IS_MPEG_HEADER macro.
This commit is contained in:
Tim-Philipp Müller 2008-05-10 20:16:21 +00:00
parent 104fed4d66
commit fed34307db
2 changed files with 31 additions and 27 deletions
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9
ChangeLog
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@ -1,3 +1,12 @@
2008-05-10 Tim-Philipp Müller <tim.muller at collabora co uk>
* gst/typefind/gsttypefindfunctions.c: (h264_video_type_find):
Don't do lots of 4-byte peeks, but use the 'new' data scan helper
for this instead; don't check if we've found enough markers after
each and every step, it's enough to do that only if we've actually
found a new marker.
Embed a G_UNLIKELY into the IS_MPEG_HEADER macro.
2008-05-10 Tim-Philipp Müller <tim.muller at collabora co uk>
* gst/typefind/gsttypefindfunctions.c:

49
gst/typefind/gsttypefindfunctions.c
View file

@ -1220,9 +1220,9 @@ static GstStaticCaps mpeg_sys_caps = GST_STATIC_CAPS ("video/mpeg, "
"systemstream = (boolean) true, mpegversion = (int) [ 1, 2 ]");
#define MPEG_SYS_CAPS gst_static_caps_get(&mpeg_sys_caps)
#define IS_MPEG_HEADER(data) ((((guint8 *)(data))[0] == 0x00) && \
#define IS_MPEG_HEADER(data) (G_UNLIKELY((((guint8 *)(data))[0] == 0x00) && \
(((guint8 *)(data))[1] == 0x00) && \
(((guint8 *)(data))[2] == 0x01))
(((guint8 *)(data))[2] == 0x01)))
#define IS_MPEG_PACK_CODE(b) ((b) == 0xBA)
#define IS_MPEG_SYS_CODE(b) ((b) == 0xBB)
@ -1630,11 +1630,11 @@ static GstStaticCaps h264_video_caps = GST_STATIC_CAPS ("video/x-h264");
static void
h264_video_type_find (GstTypeFind * tf, gpointer unused)
{
DataScanCtx c = { 0, NULL, 0 };
/* Stream consists of: a series of sync codes (00 00 00 01) followed
* by NALs
*/
guint8 *data = NULL;
int offset = 0;
int stat_slice = 0;
int stat_dpa = 0;
int stat_dpb = 0;
@ -1644,18 +1644,17 @@ h264_video_type_find (GstTypeFind * tf, gpointer unused)
int stat_pps = 0;
int nut, ref;
while (offset < H264_MAX_PROBE_LENGTH) {
data = gst_type_find_peek (tf, offset, 4);
if (data == NULL)
goto done;
while (c.offset < H264_MAX_PROBE_LENGTH) {
if (G_UNLIKELY (!data_scan_ctx_ensure_data (tf, &c, 4)))
break;
if (data && IS_MPEG_HEADER (data)) {
nut = data[3] & 0x9f; /* forbiden_zero_bit | nal_unit_type */
ref = data[3] & 0x60; /* nal_ref_idc */
if (IS_MPEG_HEADER (c.data)) {
nut = c.data[3] & 0x9f; /* forbiden_zero_bit | nal_unit_type */
ref = c.data[3] & 0x60; /* nal_ref_idc */
/* if forbiden bit is different to 0 won't be h264 */
if (nut > 0x1f)
goto done;
break;
/* collect statistics about the NAL types */
if (nut == 1)
@ -1673,23 +1672,19 @@ h264_video_type_find (GstTypeFind * tf, gpointer unused)
else if ((nut == 8) && (ref != 0))
stat_pps++;
offset += 4;
}
offset += 1;
if ((stat_slice > 4 || (stat_dpa > 4 && stat_dpb > 4 && stat_dpc > 4)) &&
stat_idr >= 1 && stat_sps >= 1 && stat_pps >= 1) {
GstCaps *caps = gst_caps_copy (H264_VIDEO_CAPS);
gst_type_find_suggest (tf, GST_TYPE_FIND_MAXIMUM - 1, caps);
gst_caps_unref (caps);
goto done;
if ((stat_slice > 4 || (stat_dpa > 4 && stat_dpb > 4 && stat_dpc > 4)) &&
stat_idr >= 1 && stat_sps >= 1 && stat_pps >= 1) {
GstCaps *caps = gst_caps_copy (H264_VIDEO_CAPS);
gst_type_find_suggest (tf, GST_TYPE_FIND_MAXIMUM - 1, caps);
gst_caps_unref (caps);
return;
}
data_scan_ctx_advance (tf, &c, 4);
}
data_scan_ctx_advance (tf, &c, 1);
}
done:
return;
}
/*** video/mpeg video stream ***/