id3demux: fix parsing of unsync'ed ID3 v2.4 tags and frames

Reversing the unsynchronisation seems to work slightly differently
for ID3 v2.3 tags and v2.4 tags: v2.3 tags don't have syncsafe frame
sizes in the frame header, so the unsynchronisation is applied to
the whole frame data including all the frame headers. v2.4 frames
have sync-safe sizes, however, so the unsynchronisation only needs
to be applied to the actual frame data, and it seems that's what's
being done as well. So we need to undo the unsynchronisation on a
per-frame basis for v2.4 tags for things to work properly.

Fixes extraction of coverart/images from APIC frames in ID3 v2.4
tags (#588148).

Add unit test for this as well.

3 files changed, 51 insertions, 4 deletions

diff --git a/tests/check/elements/id3demux.c b/tests/check/elements/id3demux.c
index ef1d4538..724461bd 100644
--- a/tests/check/elements/id3demux.c
+++ b/tests/check/elements/id3demux.c
@@ -198,7 +198,7 @@ GST_START_TEST (test_wcop)
 GST_END_TEST;
 
 static void
-check_unsync (const GstTagList * tags, const gchar * file)
+check_unsync_v23 (const GstTagList * tags, const gchar * file)
 {
   gchar *album = NULL;
   gchar *title = NULL;
@@ -220,9 +220,54 @@ check_unsync (const GstTagList * tags, const gchar * file)
   g_free (artist);
 }
 
-GST_START_TEST (test_unsync)
+GST_START_TEST (test_unsync_v23)
 {
-  run_check_for_file ("id3-577468-unsynced-tag.tag", check_unsync);
+  run_check_for_file ("id3-577468-unsynced-tag.tag", check_unsync_v23);
+}
+
+GST_END_TEST;
+
+static void
+check_unsync_v24 (const GstTagList * tags, const gchar * file)
+{
+  const GValue *val;
+  GstBuffer *buf;
+  gchar *album = NULL;
+  gchar *title = NULL;
+  gchar *artist = NULL;
+
+  fail_unless (gst_tag_list_get_string (tags, GST_TAG_TITLE, &title));
+  fail_unless (title != NULL);
+  fail_unless_equals_string (title, "Starlight");
+  g_free (title);
+
+  fail_unless (gst_tag_list_get_string (tags, GST_TAG_ALBUM, &album));
+  fail_unless (album != NULL);
+  fail_unless_equals_string (album, "L'albumRockVol.4 CD1");
+  g_free (album);
+
+  fail_unless (gst_tag_list_get_string (tags, GST_TAG_ARTIST, &artist));
+  fail_unless (artist != NULL);
+  fail_unless_equals_string (artist, "Muse");
+  g_free (artist);
+
+  val = gst_tag_list_get_value_index (tags, GST_TAG_IMAGE, 0);
+  fail_unless (val != NULL);
+  fail_unless (GST_VALUE_HOLDS_BUFFER (val));
+  buf = gst_value_get_buffer (val);
+  fail_unless (buf != NULL);
+  fail_unless (GST_BUFFER_CAPS (buf) != NULL);
+  fail_unless_equals_int (GST_BUFFER_SIZE (buf), 38022);
+  /* check for jpeg start/end markers */
+  fail_unless_equals_int (GST_BUFFER_DATA (buf)[0], 0xff);
+  fail_unless_equals_int (GST_BUFFER_DATA (buf)[1], 0xd8);
+  fail_unless_equals_int (GST_BUFFER_DATA (buf)[38020], 0xff);
+  fail_unless_equals_int (GST_BUFFER_DATA (buf)[38021], 0xd9);
+}
+
+GST_START_TEST (test_unsync_v24)
+{
+  run_check_for_file ("id3-588148-unsynced-v24.tag", check_unsync_v24);
 }
 
 GST_END_TEST;
@@ -236,7 +281,8 @@ id3demux_suite (void)
   suite_add_tcase (s, tc_chain);
   tcase_add_test (tc_chain, test_tdat_tyer);
   tcase_add_test (tc_chain, test_wcop);
-  tcase_add_test (tc_chain, test_unsync);
+  tcase_add_test (tc_chain, test_unsync_v23);
+  tcase_add_test (tc_chain, test_unsync_v24);
 
   return s;
 }
diff --git a/tests/files/Makefile.am b/tests/files/Makefile.am
index 73ab4f2d..a0a28293 100644
--- a/tests/files/Makefile.am
+++ b/tests/files/Makefile.am
@@ -5,6 +5,7 @@ EXTRA_DIST = \
 	id3-407349-2.tag \
 	id3-447000-wcop.tag \
 	id3-577468-unsynced-tag.tag \
+	id3-588148-unsynced-v24.tag \
 	pcm16sine.flv \
 	test-cert.pem \
 	test-key.pem
diff --git a/tests/files/id3-588148-unsynced-v24.tag b/tests/files/id3-588148-unsynced-v24.tag
new file mode 100644
index 00000000..099d930e
--- /dev/null
+++ b/tests/files/id3-588148-unsynced-v24.tag