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typefind: Hold off making suggestions too early for MPEG based formats

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By suggesting possible detection too early, it's possible that
the wrong format is detected. Hold off making suggestions until one
of the following conditions is met:
* Probability > GST_TYPE_FIND_LIKELY
* At least MPEG_MIN_PROBE_LENGTH bytes have been examined
* EOS, in which case the best guess wins

Fixes #628
This commit is contained in:
Thomas Bluemel 2019-06-26 15:53:11 -06:00 committed by Thomas Bluemel
parent 8f125fb4d9
commit 36319169d0
1 changed files with 36 additions and 8 deletions
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44
gst/typefind/gsttypefindfunctions.c
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@ -2159,12 +2159,27 @@ static GstStaticCaps mpeg_sys_caps = GST_STATIC_CAPS ("video/mpeg, "
#define IS_MPEG_PES_HEADER(data) (IS_MPEG_HEADER (data) && \
IS_MPEG_PES_CODE (((guint8 *)(data))[3]))
#define MPEG_MIN_PROBE_LENGTH (4 * 1024) /* Examine at least 4kB of data to
* give the various MPEG formats enough
* data to avoid mis-detections. */
#define MPEG2_MAX_PROBE_LENGTH (128 * 1024) /* 128kB should be 64 packs of the
* most common 2kB pack size. */
#define MPEG2_MIN_SYS_HEADERS 2
#define MPEG2_MAX_SYS_HEADERS 5
static gboolean
mpeg_should_suggest (GstTypeFind * tf, GstTypeFindProbability prob, guint size)
{
/* only suggest if we probed at least a certain amount of data, if
* we have a high confindence, or when we reached eos. This gives
* various MPEG based formats a better chance of correctly identifying
* the data. */
return prob > GST_TYPE_FIND_LIKELY || size >= MPEG_MIN_PROBE_LENGTH ||
gst_type_find_is_eos (tf);
}
static gboolean
mpeg_sys_is_valid_pack (GstTypeFind * tf, const guint8 * data, guint len,
guint * pack_size)
@ -2407,6 +2422,9 @@ suggest:
if (data0 != first_sync && prob >= 10)
prob -= 10;
if (!mpeg_should_suggest (tf, prob, end - data0))
return;
GST_LOG ("Suggesting MPEG %d system stream, %d packs, %d pes, prob %u%%",
mpegversion, pack_headers, pes_headers, prob);
@ -2505,6 +2523,9 @@ mpeg_ts_type_find (GstTypeFind * tf, gpointer unused)
* found, 40% -> 100% */
probability = MIN (10 * found, GST_TYPE_FIND_MAXIMUM);
if (!mpeg_should_suggest (tf, probability, size))
return;
gst_type_find_suggest_simple (tf, probability, "video/mpegts",
"systemstream", G_TYPE_BOOLEAN, TRUE,
"packetsize", G_TYPE_INT, pack_sizes[p], NULL);
@ -2664,7 +2685,8 @@ mpeg4_video_type_find (GstTypeFind * tf, gpointer unused)
else if (seen_vos && seen_vol)
probability = GST_TYPE_FIND_POSSIBLE - 20;
gst_type_find_suggest (tf, probability, MPEG4_VIDEO_CAPS);
if (mpeg_should_suggest (tf, probability, c.size))
gst_type_find_suggest (tf, probability, MPEG4_VIDEO_CAPS);
}
}
@ -2807,7 +2829,8 @@ h264_video_type_find (GstTypeFind * tf, gpointer unused)
GST_LOG ("good:%d, bad:%d, pps:%d, sps:%d, idr:%d ssps:%d", good, bad,
seen_pps, seen_sps, seen_idr, seen_ssps);
if (seen_sps && seen_pps && seen_idr && good >= 10 && bad < 4) {
if (seen_sps && seen_pps && seen_idr && good >= 10 && bad < 4
&& mpeg_should_suggest (tf, GST_TYPE_FIND_LIKELY, c.size)) {
gst_type_find_suggest (tf, GST_TYPE_FIND_LIKELY, H264_VIDEO_CAPS);
return;
}
@ -2820,7 +2843,8 @@ h264_video_type_find (GstTypeFind * tf, gpointer unused)
GST_LOG ("good:%d, bad:%d, pps:%d, sps:%d, idr:%d ssps=%d", good, bad,
seen_pps, seen_sps, seen_idr, seen_ssps);
if (good >= 2 && bad == 0) {
if (good >= 2 && bad == 0
&& mpeg_should_suggest (tf, GST_TYPE_FIND_POSSIBLE, c.size)) {
gst_type_find_suggest (tf, GST_TYPE_FIND_POSSIBLE, H264_VIDEO_CAPS);
}
}
@ -2900,7 +2924,8 @@ h265_video_type_find (GstTypeFind * tf, gpointer unused)
GST_LOG ("good:%d, bad:%d, pps:%d, sps:%d, vps:%d, irap:%d", good, bad,
seen_pps, seen_sps, seen_vps, seen_irap);
if (seen_sps && seen_pps && seen_irap && good >= 10 && bad < 4) {
if (seen_sps && seen_pps && seen_irap && good >= 10 && bad < 4
&& mpeg_should_suggest (tf, GST_TYPE_FIND_LIKELY, c.size)) {
gst_type_find_suggest (tf, GST_TYPE_FIND_LIKELY, H265_VIDEO_CAPS);
return;
}
@ -2913,7 +2938,8 @@ h265_video_type_find (GstTypeFind * tf, gpointer unused)
GST_LOG ("good:%d, bad:%d, pps:%d, sps:%d, vps:%d, irap:%d", good, bad,
seen_pps, seen_sps, seen_vps, seen_irap);
if (good >= 2 && bad == 0) {
if (good >= 2 && bad == 0
&& mpeg_should_suggest (tf, GST_TYPE_FIND_POSSIBLE, c.size)) {
gst_type_find_suggest (tf, GST_TYPE_FIND_POSSIBLE, H265_VIDEO_CAPS);
}
}
@ -3020,9 +3046,11 @@ mpeg_video_stream_type_find (GstTypeFind * tf, gpointer unused)
else if (seen_seq)
probability = GST_TYPE_FIND_POSSIBLE - 20;
gst_type_find_suggest_simple (tf, probability, "video/mpeg",
"systemstream", G_TYPE_BOOLEAN, FALSE,
"mpegversion", G_TYPE_INT, 1, "parsed", G_TYPE_BOOLEAN, FALSE, NULL);
if (mpeg_should_suggest (tf, probability, c.size)) {
gst_type_find_suggest_simple (tf, probability, "video/mpeg",
"systemstream", G_TYPE_BOOLEAN, FALSE,
"mpegversion", G_TYPE_INT, 1, "parsed", G_TYPE_BOOLEAN, FALSE, NULL);
}
}
}