tsdemux: Add new API for fetching extended descriptors

Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-bad/-/merge_requests/1555>

gst-libs/gst/mpegts/gstmpegtsdescriptor.c

@@ -988,6 +988,38 @@ gst_mpegts_find_descriptor (GPtrArray * descriptors, guint8 tag)
   return NULL;
 }
 
+/**
+ * gst_mpegts_find_descriptor_with_extension:
+ * @descriptors: (element-type GstMpegtsDescriptor) (transfer none): an array
+ * of #GstMpegtsDescriptor
+ * @tag: the tag to look for
+ *
+ * Finds the first descriptor of type @tag with @tag_extension in the array.
+ *
+ * Note: To look for descriptors that can be present more than once in an
+ * array of descriptors, iterate the #GArray manually.
+ *
+ * Returns: (transfer none): the first descriptor matchin @tag with @tag_extension, else %NULL.
+ *
+ * Since: 1.20
+ */
+const GstMpegtsDescriptor *
+gst_mpegts_find_descriptor_with_extension (GPtrArray * descriptors, guint8 tag,
+    guint8 tag_extension)
+{
+  guint i, nb_desc;
+
+  g_return_val_if_fail (descriptors != NULL, NULL);
+
+  nb_desc = descriptors->len;
+  for (i = 0; i < nb_desc; i++) {
+    GstMpegtsDescriptor *desc = g_ptr_array_index (descriptors, i);
+    if ((desc->tag == tag) && (desc->tag_extension == tag_extension))
+      return (const GstMpegtsDescriptor *) desc;
+  }
+  return NULL;
+}
+
 /* GST_MTS_DESC_REGISTRATION (0x05) */
 /**
  * gst_mpegts_descriptor_from_registration:

gst-libs/gst/mpegts/gstmpegtsdescriptor.h

@@ -274,6 +274,10 @@ GST_MPEGTS_API
 const GstMpegtsDescriptor * gst_mpegts_find_descriptor (GPtrArray *descriptors,
 							guint8 tag);
 
+GST_MPEGTS_API
+const GstMpegtsDescriptor * gst_mpegts_find_descriptor_with_extension (GPtrArray *descriptors,
+							guint8 tag, guint8 tag_extension);
+
 /* GST_MTS_DESC_REGISTRATION (0x05) */
 
 GST_MPEGTS_API
@@ -375,6 +379,12 @@ GST_MPEGTS_API
 GstMpegtsDescriptor *
 gst_mpegts_descriptor_from_custom (guint8 tag, const guint8 *data, gsize length);
 
+
+/**
+ * gst_mpegts_descriptor_from_custom_with_extension:
+ *
+ * Since: 1.20
+ */
 GST_MPEGTS_API
 GstMpegtsDescriptor *
 gst_mpegts_descriptor_from_custom_with_extension (guint8 tag, guint8 tag_extension, const guint8 *data, gsize length);

gst/mpegtsdemux/mpegtsbase.c

@@ -325,6 +325,20 @@ mpegts_get_descriptor_from_stream (MpegTSBaseStream * stream, guint8 tag)
   return gst_mpegts_find_descriptor (pmt->descriptors, tag);
 }
 
+const GstMpegtsDescriptor *
+mpegts_get_descriptor_from_stream_with_extension (MpegTSBaseStream * stream,
+    guint8 tag, guint8 tag_extension)
+{
+  GstMpegtsPMTStream *pmt = stream->stream;
+
+  GST_DEBUG ("Searching for tag 0x%02x tag_extension 0x%02x "
+      "in stream 0x%04x (stream_type 0x%02x)",
+      tag, tag_extension, stream->pid, stream->stream_type);
+
+  return gst_mpegts_find_descriptor_with_extension (pmt->descriptors, tag,
+      tag_extension);
+}
+
 typedef struct
 {
   gboolean res;

gst/mpegtsdemux/mpegtsbase.h

@@ -234,6 +234,8 @@ G_GNUC_INTERNAL MpegTSBaseProgram *mpegts_base_get_program (MpegTSBase * base, g
 G_GNUC_INTERNAL MpegTSBaseProgram *mpegts_base_add_program (MpegTSBase * base, gint program_number, guint16 pmt_pid);
 
 G_GNUC_INTERNAL const GstMpegtsDescriptor *mpegts_get_descriptor_from_stream (MpegTSBaseStream * stream, guint8 tag);
+G_GNUC_INTERNAL const GstMpegtsDescriptor *mpegts_get_descriptor_from_stream_with_extension (MpegTSBaseStream * stream,
+    guint8 tag, guint8 tag_extension);
 G_GNUC_INTERNAL const GstMpegtsDescriptor *mpegts_get_descriptor_from_program (MpegTSBaseProgram * program, guint8 tag);
 
 G_GNUC_INTERNAL gboolean

gst/mpegtsdemux/tsdemux.c

@@ -1266,10 +1266,9 @@ create_pad_for_stream (MpegTSBase * base, MpegTSBaseStream * bstream,
        * types also, depending on registratino descriptors also
        */
 
-      desc =
+      desc = mpegts_get_descriptor_from_stream_with_extension (bstream,
-          mpegts_get_descriptor_from_stream (bstream,
+          GST_MTS_DESC_DVB_EXTENSION, GST_MTS_DESC_EXT_DVB_AC4);
-          GST_MTS_DESC_DVB_EXTENSION);
+      if (desc) {
-      if (desc != NULL && desc->tag_extension == GST_MTS_DESC_EXT_DVB_AC4) {
         GST_LOG ("ac4 audio");
         is_audio = TRUE;
         caps = gst_caps_new_empty_simple ("audio/x-ac4");