encodebin: Add timestamper elements when available

Timestamper elements are made to ensure stream timestamp are clean and
ready to be used by muxers, we should make use of them to cleanup
streams before muxing.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/3779>

subprojects/gst-plugins-base/gst/encoding/gstencodebasebin.c

@@ -150,6 +150,7 @@ struct _StreamGroup
   GstElement *fakesink;         /* Fakesink (can be NULL) */
   GstElement *combiner;
   GstElement *parser;
+  GstElement *timestamper;
   GstElement *smartencoder;
   GstElement *smart_capsfilter;
   gulong smart_capsfilter_sid;
@@ -418,6 +419,10 @@ gst_encode_base_bin_dispose (GObject * object)
     gst_plugin_feature_list_free (ebin->parsers);
   ebin->parsers = NULL;
 
+  if (ebin->timestampers)
+    gst_plugin_feature_list_free (ebin->timestampers);
+  ebin->timestampers = NULL;
+
   gst_encode_base_bin_tear_down_profile (ebin);
 
   if (ebin->raw_video_caps)
@@ -451,6 +456,10 @@ gst_encode_base_bin_init (GstEncodeBaseBin * encode_bin)
       gst_element_factory_list_get_elements (GST_ELEMENT_FACTORY_TYPE_PARSER,
       GST_RANK_MARGINAL);
 
+  encode_bin->timestampers =
+      gst_element_factory_list_get_elements
+      (GST_ELEMENT_FACTORY_TYPE_TIMESTAMPER, GST_RANK_MARGINAL);
+
   encode_bin->raw_video_caps = gst_caps_from_string ("video/x-raw");
   encode_bin->raw_audio_caps = gst_caps_from_string ("audio/x-raw");
   /* encode_bin->raw_text_caps = */
@@ -813,14 +822,16 @@ no_stream_group:
   }
 }
 
-/* Create a parser for the given stream profile */
+/* Filters processing elements (can be a parser or a timestamper) from
+ * @all_processors and returns the best fit (or %NULL if none matches)
+ */
 static inline GstElement *
-_get_parser (GstEncodeBaseBin * ebin, GstEncodingProfile * sprof,
-    GstElement * encoder)
+_create_compatible_processor (GList * all_processors,
+    GstEncodingProfile * sprof, GstElement * encoder)
 {
-  GList *parsers1, *parsers, *tmp;
-  GstElement *parser = NULL;
-  GstElementFactory *parserfact = NULL;
+  GList *processors1, *processors, *tmp;
+  GstElement *processor = NULL;
+  GstElementFactory *factory = NULL;
   GstCaps *format = NULL;
 
   if (encoder) {
@@ -835,39 +846,40 @@ _get_parser (GstEncodeBaseBin * ebin, GstEncodingProfile * sprof,
     format = gst_encoding_profile_get_format (sprof);
   }
 
-  GST_DEBUG ("Getting list of parsers for format %" GST_PTR_FORMAT, format);
+  GST_DEBUG ("Getting list of processors for format %" GST_PTR_FORMAT, format);
 
-  /* FIXME : requesting twice the parsers twice is a bit ugly, we should
-   * have a method to request on more than one condition */
-  parsers1 =
-      gst_element_factory_list_filter (ebin->parsers, format,
+  /* FIXME : requesting twice the processing element twice is a bit ugly, we
+   * should have a method to request on more than one condition */
+  processors1 =
+      gst_element_factory_list_filter (all_processors, format,
       GST_PAD_SRC, FALSE);
-  parsers =
-      gst_element_factory_list_filter (parsers1, format, GST_PAD_SINK, FALSE);
-  gst_plugin_feature_list_free (parsers1);
+  processors =
+      gst_element_factory_list_filter (processors1, format, GST_PAD_SINK,
+      FALSE);
+  gst_plugin_feature_list_free (processors1);
 
-  if (G_UNLIKELY (parsers == NULL)) {
-    GST_DEBUG ("Couldn't find any compatible parsers");
+  if (G_UNLIKELY (processors == NULL)) {
+    GST_DEBUG ("Couldn't find any compatible processing element");
     goto beach;
   }
 
-  for (tmp = parsers; tmp; tmp = tmp->next) {
+  for (tmp = processors; tmp; tmp = tmp->next) {
     /* FIXME : We're only picking the first one so far */
     /* FIXME : signal the user if he wants this */
-    parserfact = (GstElementFactory *) tmp->data;
+    factory = (GstElementFactory *) tmp->data;
     break;
   }
 
-  if (parserfact)
-    parser = gst_element_factory_create (parserfact, NULL);
+  if (factory)
+    processor = gst_element_factory_create (factory, NULL);
 
-  gst_plugin_feature_list_free (parsers);
+  gst_plugin_feature_list_free (processors);
 
 beach:
   if (format)
     gst_caps_unref (format);
 
-  return parser;
+  return processor;
 }
 
 static gboolean
@@ -1338,7 +1350,7 @@ setup_smart_encoder (GstEncodeBaseBin * ebin, GstEncodingProfile * sprof,
     goto err;
   }
 
-  parser = _get_parser (ebin, sprof, encoder);
+  parser = _create_compatible_processor (ebin->parsers, sprof, encoder);
   sgroup->smart_capsfilter = gst_element_factory_make ("capsfilter", NULL);
   reencoder_bin = gst_bin_new (NULL);
 
@@ -1562,7 +1574,9 @@ _create_stream_group (GstEncodeBaseBin * ebin, GstEncodingProfile * sprof,
     goto outfilter_link_failure;
   last = sgroup->outfilter;
 
-  sgroup->parser = _get_parser (ebin, sgroup->profile, sgroup->encoder);
+  sgroup->parser =
+      _create_compatible_processor (ebin->parsers, sgroup->profile,
+      sgroup->encoder);
   if (sgroup->parser != NULL) {
     GST_DEBUG ("Got a parser %s", GST_ELEMENT_NAME (sgroup->parser));
     gst_bin_add (GST_BIN (ebin), sgroup->parser);
@@ -1572,6 +1586,17 @@ _create_stream_group (GstEncodeBaseBin * ebin, GstEncodingProfile * sprof,
     last = sgroup->parser;
   }
 
+  sgroup->timestamper =
+      _create_compatible_processor (ebin->timestampers, sprof, encoder);
+  if (sgroup->timestamper != NULL) {
+    GST_DEBUG ("Got a timestamper %s", GST_ELEMENT_NAME (sgroup->timestamper));
+    gst_bin_add (GST_BIN (ebin), sgroup->timestamper);
+    tosync = g_list_append (tosync, sgroup->timestamper);
+    if (G_UNLIKELY (!gst_element_link (sgroup->timestamper, last)))
+      goto parser_link_failure;
+    last = sgroup->timestamper;
+  }
+
   /* Stream combiner */
   sgroup->combiner = g_object_new (GST_TYPE_STREAM_COMBINER, NULL);
 

subprojects/gst-plugins-base/gst/encoding/gstencodebasebin.h

@@ -62,6 +62,7 @@ struct _GstEncodeBaseBin
   GList *formatters;
   GList *encoders;
   GList *parsers;
+  GList *timestampers;
 
   /* Increasing counter for unique pad name */
   guint last_pad_id;