qtdemux: Detect and expose CEA 608/708 Closed Caption tracksHEADmaster

https://bugzilla.gnome.org/show_bug.cgi?id=606643

3 files changed, 63 insertions, 2 deletions

diff --git a/gst/isomp4/fourcc.h b/gst/isomp4/fourcc.h
index be5c7c04e..e3503cb59 100644
--- a/gst/isomp4/fourcc.h
+++ b/gst/isomp4/fourcc.h
@@ -95,6 +95,10 @@ G_BEGIN_DECLS
 #define FOURCC_avc1     GST_MAKE_FOURCC('a','v','c','1')
 #define FOURCC_avc3     GST_MAKE_FOURCC('a','v','c','3')
 #define FOURCC_avcC     GST_MAKE_FOURCC('a','v','c','C')
+#define FOURCC_c608     GST_MAKE_FOURCC('c','6','0','8')
+#define FOURCC_c708     GST_MAKE_FOURCC('c','7','0','8')
+#define FOURCC_cdat     GST_MAKE_FOURCC('c','d','a','t')
+#define FOURCC_clcp     GST_MAKE_FOURCC('c','l','c','p')
 #define FOURCC_clip     GST_MAKE_FOURCC('c','l','i','p')
 #define FOURCC_cmov     GST_MAKE_FOURCC('c','m','o','v')
 #define FOURCC_cmvd     GST_MAKE_FOURCC('c','m','v','d')
diff --git a/gst/isomp4/qtdemux.c b/gst/isomp4/qtdemux.c
index 4fda82a82..8a12327a8 100644
--- a/gst/isomp4/qtdemux.c
+++ b/gst/isomp4/qtdemux.c
@@ -5352,6 +5352,33 @@ gst_qtdemux_align_buffer (GstQTDemux * demux,
   return buffer;
 }
 
+static guint8 *
+extract_cc_from_cdat (const guint8 * data, gsize size, gsize * cclen)
+{
+  guint8 *res = NULL;
+  guint32 atom_length, fourcc;
+
+  *cclen = 0;
+  if (size < 8)
+    goto invalid_cdat;
+  atom_length = QT_UINT32 (data);
+  fourcc = QT_FOURCC (data + 4);
+
+  if (G_UNLIKELY (atom_length > size || atom_length == 8
+          || fourcc != FOURCC_cdat))
+    goto invalid_cdat;
+
+  *cclen = atom_length - 8;
+  res = g_memdup (data + 8, *cclen);
+
+  return res;
+
+  /* Errors */
+invalid_cdat:
+  GST_WARNING ("[cdat] atom is too small or invalid");
+  return NULL;
+}
+
 /* the input buffer metadata must be writable,
  * but time/duration etc not yet set and need not be preserved */
 static GstBuffer *
@@ -5372,7 +5399,7 @@ gst_qtdemux_process_buffer (GstQTDemux * qtdemux, QtDemuxStream * stream,
 
   if (G_UNLIKELY (stream->subtype != FOURCC_text
           && stream->subtype != FOURCC_sbtl &&
-          stream->subtype != FOURCC_subp)) {
+          stream->subtype != FOURCC_subp && stream->subtype != FOURCC_clcp)) {
     return buf;
   }
 
@@ -5390,6 +5417,23 @@ gst_qtdemux_process_buffer (GstQTDemux * qtdemux, QtDemuxStream * stream,
     return buf;
   }
 
+  if (stream->subtype == FOURCC_clcp) {
+    guint8 *cc;
+    gsize cclen = 0;
+    /* For closed caption, we need to extract the information from the
+     * [cdat] atom */
+    cc = extract_cc_from_cdat (map.data, map.size, &cclen);
+    gst_buffer_unmap (buf, &map);
+    gst_buffer_unref (buf);
+    if (cc) {
+      buf = _gst_buffer_new_wrapped (cc, cclen, g_free);
+    } else {
+      /* Conversion failed or there's nothing */
+      buf = NULL;
+    }
+    return buf;
+  }
+
   nsize = GST_READ_UINT16_BE (map.data);
   nsize = MIN (nsize, map.size - 2);
 
@@ -11519,7 +11563,8 @@ qtdemux_parse_trak (GstQTDemux * qtdemux, GNode * trak)
       }
       entry->sampled = TRUE;
     } else if (stream->subtype == FOURCC_subp || stream->subtype == FOURCC_text
-        || stream->subtype == FOURCC_sbtl || stream->subtype == FOURCC_subt) {
+        || stream->subtype == FOURCC_sbtl || stream->subtype == FOURCC_subt
+        || stream->subtype == FOURCC_clcp) {
 
       entry->sampled = TRUE;
       entry->sparse = TRUE;
@@ -14404,6 +14449,17 @@ qtdemux_sub_caps (GstQTDemux * qtdemux, QtDemuxStream * stream,
       _codec ("XML subtitles");
       caps = gst_caps_new_empty_simple ("application/ttml+xml");
       break;
+    case FOURCC_c608:
+      _codec ("CEA 608 Closed Caption");
+      caps = gst_caps_new_empty_simple ("closedcaption/x-cea-608");
+      stream->need_process = TRUE;
+      break;
+    case FOURCC_c708:
+      _codec ("CEA 708 Closed Caption");
+      caps = gst_caps_new_empty_simple ("closedcaption/x-cea-708");
+      stream->need_process = TRUE;
+      break;
+
     default:
     {
       caps = _get_unknown_codec_name ("text", fourcc);
diff --git a/gst/isomp4/qtdemux_types.c b/gst/isomp4/qtdemux_types.c
index 88db8c2ce..1d5840394 100644
--- a/gst/isomp4/qtdemux_types.c
+++ b/gst/isomp4/qtdemux_types.c
@@ -213,6 +213,7 @@ static const QtNodeType qt_node_types[] = {
   {FOURCC_pssh, "protection system specific header", 0},
   {FOURCC_tenc, "track encryption", 0},
   {FOURCC_stpp, "XML subtitle sample entry", 0},
+  {FOURCC_clcp, "Closed Caption", 0},
   {0, "unknown", 0,},
 };