+2008-04-30 Tim-Philipp Müller <tim.muller at collabora co uk>
+
+ * gst/typefind/gsttypefindfunctions.c:
+ (mpeg_video_stream_ctx_ensure_data), (mpeg_video_stream_type_find),
+ (plugin_init):
+ Rework mpeg video stream typefinding a bit more: make sure sequence,
+ GOP, picture and slice headers appear in the order they should and
+ that we've in fact at least had one of each; fix picture header
+ detection; decouple picture and slice header check - don't assume
+ they're at a fixed offset, there may be extra data in between. Also,
+ announce varying degrees of probability depending on what we found
+ exactly (multiple pictures, at least one picture, just sequence and
+ GOP headers). Finally, in _ensure_data(), take into account that we
+ might be typefinding smaller amounts of data, such as the first
+ buffer of a stream, so fall back to the minimum size needed as long
+ as that's available, instead of erroring out if there's less than
+ 2kB of data. Fixes #526173. Conveniently also doesn't recognise the
+ fuzzed file from #399342 as valid.
+
2008-04-30 Michael Smith <msmith@songbirdnest.com>
* ext/theora/theoradec.c:
* gst/typefind/gsttypefindfunctions.c: (MpegVideoStreamCtx),
(mpeg_video_stream_ctx_advance), (mpeg_video_stream_ctx_ensure_data),
(mpeg_video_stream_type_find):
- Refactor a bit: use context structure to track parsing offset and size of
- available data and make the code a bit clearer. Fixes bad memory access
- in #356937.
+ Refactor a bit: use context structure to track parsing offset and
+ size of available data and make the code a bit clearer. Fixes bad
+ memory access in #356937.
2008-04-28 Michael Smith <msmith@songbirdnest.com>
static GstStaticCaps mpeg_video_caps = GST_STATIC_CAPS ("video/mpeg, "
"systemstream = (boolean) false");
#define MPEG_VIDEO_CAPS gst_static_caps_get(&mpeg_video_caps)
-static void
-mpeg_video_type_find (GstTypeFind * tf, gpointer unused)
-{
- static const guint8 sequence_header[] = { 0x00, 0x00, 0x01, 0xb3 };
- guint8 *data = NULL;
-
- data = gst_type_find_peek (tf, 0, 8);
-
- if (data && memcmp (data, sequence_header, 4) == 0) {
- GstCaps *caps = gst_caps_copy (MPEG_VIDEO_CAPS);
-
- gst_structure_set (gst_caps_get_structure (caps, 0), "mpegversion",
- G_TYPE_INT, 1, NULL);
- gst_type_find_suggest (tf, GST_TYPE_FIND_POSSIBLE, caps);
- gst_caps_unref (caps);
- }
-}
/*
* Idea is the same as MPEG system stream typefinding: We check each
return TRUE;
c->data = gst_type_find_peek (tf, c->offset, GST_MPEGVID_TYPEFIND_SYNC_SIZE);
- if (c->data == NULL)
- return FALSE;
+ if (c->data != NULL) {
+ c->size = GST_MPEGVID_TYPEFIND_SYNC_SIZE;
+ return TRUE;
+ }
- c->size = GST_MPEGVID_TYPEFIND_SYNC_SIZE;
- return TRUE;
+ /* try min_size as fallback: we might be typefinding the first buffer of the
+ * stream and not have as much data available as we'd like */
+ c->data = gst_type_find_peek (tf, c->offset, min_len);
+ if (c->data != NULL) {
+ c->size = min_len;
+ return TRUE;
+ }
+
+ return FALSE;
}
static void
mpeg_video_stream_type_find (GstTypeFind * tf, gpointer unused)
{
MpegVideoStreamCtx c = { 0, NULL, 0 };
+ gboolean seen_seq = FALSE;
+ gboolean seen_gop = FALSE;
+ guint num_pic_headers = 0;
gint found = 0;
- while (1) {
- if (found >= GST_MPEGVID_TYPEFIND_TRY_PICTURES) {
- GstCaps *caps = gst_caps_copy (MPEG_VIDEO_CAPS);
-
- gst_structure_set (gst_caps_get_structure (caps, 0), "mpegversion",
- G_TYPE_INT, 1, NULL);
- gst_type_find_suggest (tf, GST_TYPE_FIND_MAXIMUM - 2, caps);
- gst_caps_unref (caps);
- return;
- }
-
- if (c.offset >= GST_MPEGVID_TYPEFIND_TRY_SYNC)
+ while (c.offset < GST_MPEGVID_TYPEFIND_TRY_SYNC) {
+ if (found >= GST_MPEGVID_TYPEFIND_TRY_PICTURES)
break;
if (!mpeg_video_stream_ctx_ensure_data (tf, &c, 5))
break;
- if (IS_MPEG_HEADER (c.data)) {
- /* An MPEG PACK header indicates that this isn't an elementary stream */
- if (IS_MPEG_PACK_CODE (c.data[3])) {
- if (mpeg_sys_is_valid_pack (tf, c.data, c.size, NULL))
- break;
- }
+ if (!IS_MPEG_HEADER (c.data))
+ goto next;
- /* are we a sequence (0xB3) header? */
- if (c.data[3] == 0xB3) {
- mpeg_video_stream_ctx_advance (tf, &c, 4 + 8);
- continue;
- }
+ /* a pack header indicates that this isn't an elementary stream */
+ if (c.data[3] == 0xBA && mpeg_sys_is_valid_pack (tf, c.data, c.size, NULL))
+ return;
- /* ... or a GOP (0xB8) header? */
- if (c.data[3] == 0xB8) {
- mpeg_video_stream_ctx_advance (tf, &c, 8);
- continue;
- }
+ /* do we have a sequence header? */
+ if (c.data[3] == 0xB3) {
+ seen_seq = TRUE;
+ mpeg_video_stream_ctx_advance (tf, &c, 4 + 8);
+ continue;
+ }
- /* ... else, we should now see an image header ... */
- /* is [4] really what we want here, not [3]? Won't [4] == 0 only work for
- * the first image or the first few images? (tpm) */
- if (c.data[4] == 0x00) {
- mpeg_video_stream_ctx_advance (tf, &c, 8);
+ /* we really want to see a sequence header first */
+ if (!seen_seq)
+ goto next;
- if (!mpeg_video_stream_ctx_ensure_data (tf, &c, 5))
- break;
+ /* next, a GOP header would be nice */
+ if (c.data[3] == 0xB8) {
+ seen_gop = TRUE;
+ mpeg_video_stream_ctx_advance (tf, &c, 8);
+ continue;
+ }
- /* .. followed by a slice header */
- if ((IS_MPEG_HEADER (c.data + 0) && c.data[3] == 0x01) ||
- (IS_MPEG_HEADER (c.data + 1) && c.data[4] == 0x01)) {
- mpeg_video_stream_ctx_advance (tf, &c, 4);
- found += 1;
- continue;
- }
- }
+ /* we really want to see a sequence+GOP header before continuing */
+ if (!seen_gop)
+ goto next;
+
+ /* now that we've had a sequence+GOP, we'd like to see a picture header */
+ if (c.data[3] == 0x00) {
+ ++num_pic_headers;
+ mpeg_video_stream_ctx_advance (tf, &c, 8);
+ continue;
}
+ /* ... each followed by a slice header with slice_vertical_pos=1 */
+ if (c.data[3] == 0x01 && num_pic_headers > found) {
+ mpeg_video_stream_ctx_advance (tf, &c, 4);
+ found += 1;
+ continue;
+ }
+
+ next:
+
mpeg_video_stream_ctx_advance (tf, &c, 1);
}
+
+ if (found > 0 || num_pic_headers > 0) {
+ GstTypeFindProbability probability;
+ GstCaps *caps;
+
+ if (found >= GST_MPEGVID_TYPEFIND_TRY_PICTURES)
+ probability = GST_TYPE_FIND_MAXIMUM - 2;
+ else if (found > 0)
+ probability = GST_TYPE_FIND_POSSIBLE + 1;
+ else
+ probability = GST_TYPE_FIND_POSSIBLE - 10;
+
+ caps = gst_caps_copy (MPEG_VIDEO_CAPS);
+ gst_caps_set_simple (caps, "mpegversion", G_TYPE_INT, 1, NULL);
+ gst_type_find_suggest (tf, probability, caps);
+ gst_caps_unref (caps);
+ }
}
/*** audio/x-aiff ***/
mpeg_ts_type_find, mpeg_ts_exts, MPEGTS_CAPS, NULL, NULL);
TYPE_FIND_REGISTER (plugin, "application/ogg", GST_RANK_PRIMARY,
ogganx_type_find, ogg_exts, OGGANX_CAPS, NULL, NULL);
- TYPE_FIND_REGISTER (plugin, "video/mpeg,elementary", GST_RANK_SECONDARY,
- mpeg_video_type_find, mpeg_video_exts, MPEG_VIDEO_CAPS, NULL, NULL);
- TYPE_FIND_REGISTER (plugin, "video/mpeg-stream", GST_RANK_MARGINAL,
+ TYPE_FIND_REGISTER (plugin, "video/mpeg-elementary", GST_RANK_MARGINAL,
mpeg_video_stream_type_find, mpeg_video_exts, MPEG_VIDEO_CAPS, NULL,
NULL);
TYPE_FIND_REGISTER (plugin, "video/mpeg4", GST_RANK_PRIMARY,
projects / platform / upstream / gstreamer.git / commitdiff