From 5ccaa595a9d6e7fcc18703037fb53c861be1a82e Mon Sep 17 00:00:00 2001
From: Thibault Saunier <tsaunier@igalia.com>
Date: Thu, 19 Nov 2020 18:31:34 -0300
Subject: [PATCH] transcodebin: Avoid plugin converter if filter handles ANY
 caps

For example identity or clocksync or this kind of elements can be
used with any data flow and we should not enforce decoding to row in
that case.
---
 gst/transcode/gsttranscodebin.c | 36 ++++++++++++++++++++++++++++-----
 1 file changed, 31 insertions(+), 5 deletions(-)

diff --git a/gst/transcode/gsttranscodebin.c b/gst/transcode/gsttranscodebin.c
index 778992f7e3..3ea6ebfcd8 100644
--- a/gst/transcode/gsttranscodebin.c
+++ b/gst/transcode/gsttranscodebin.c
@@ -148,6 +148,26 @@ post_missing_plugin_error (GstElement * dec, const gchar * element_name)
 }
 /* *INDENT-ON* */
 
+static gboolean
+filter_handles_any (GstElement * filter)
+{
+  GList *tmp;
+
+  for (tmp = gst_element_get_pad_template_list (filter); tmp; tmp = tmp->next) {
+    GstPadTemplate *tmpl = tmp->data;
+    GstCaps *caps = gst_pad_template_get_caps (tmpl);
+
+    if (!gst_caps_is_any (caps)) {
+      gst_caps_unref (caps);
+      return FALSE;
+    }
+
+    gst_caps_unref (caps);
+  }
+
+  return gst_element_get_pad_template_list (filter) != NULL;
+}
+
 static GstPad *
 _insert_filter (GstTranscodeBin * self, GstPad * sinkpad, GstPad * pad,
     GstCaps * caps)
@@ -163,14 +183,16 @@ _insert_filter (GstTranscodeBin * self, GstPad * sinkpad, GstPad * pad,
   if (self->video_filter && g_str_has_prefix (media_type, "video")) {
     audio = FALSE;
 
-    if (!g_strcmp0 (media_type, "video/x-raw"))
+    if (!g_strcmp0 (media_type, "video/x-raw")
+        || filter_handles_any (self->video_filter))
       filter = self->video_filter;
     else
       GST_ERROR_OBJECT (pad, "decodebin pad does not produce raw data (%"
           GST_PTR_FORMAT "), cannot add video filter '%s'", caps,
           GST_ELEMENT_NAME (self->video_filter));
   } else if (self->audio_filter && g_str_has_prefix (media_type, "audio")) {
-    if (!g_strcmp0 (media_type, "audio/x-raw"))
+    if (!g_strcmp0 (media_type, "audio/x-raw")
+        || filter_handles_any (self->audio_filter))
       filter = self->audio_filter;
     else
       GST_ERROR_OBJECT (pad, "decodebin pad does not produce raw data (%"
@@ -181,7 +203,8 @@ _insert_filter (GstTranscodeBin * self, GstPad * sinkpad, GstPad * pad,
   if (!filter)
     return pad;
 
-  if ((filter_parent = gst_object_get_parent (GST_OBJECT (filter)))) {
+  filter_parent = gst_object_get_parent (GST_OBJECT (filter));
+  if (filter_parent != GST_OBJECT_CAST (self)) {
     GST_WARNING_OBJECT (self,
         "Filter already in use (inside %" GST_PTR_FORMAT ").", filter_parent);
     GST_FIXME_OBJECT (self,
@@ -191,13 +214,16 @@ _insert_filter (GstTranscodeBin * self, GstPad * sinkpad, GstPad * pad,
     return pad;
   }
 
+  gst_object_unref (filter_parent);
   /* We are guaranteed filters only have 1 unique sinkpad and srcpad */
   GST_OBJECT_LOCK (filter);
   filter_sink = filter->sinkpads->data;
   filter_src = filter->srcpads->data;
   GST_OBJECT_UNLOCK (filter);
 
-  if (audio)
+  if (filter_handles_any (filter))
+    convert = gst_element_factory_make ("identity", NULL);
+  else if (audio)
     convert = gst_element_factory_make ("audioconvert", NULL);
   else
     convert = gst_element_factory_make ("videoconvert", NULL);
@@ -639,7 +665,7 @@ _setup_avoid_reencoding (GstTranscodeBin * self)
         && self->audio_filter)
       filter = self->audio_filter;
 
-    if (!filter) {
+    if (!filter || filter_handles_any (filter)) {
       GST_DEBUG_OBJECT (self,
           "adding %" GST_PTR_FORMAT " as output caps to decodebin", encodecaps);
       gst_caps_append (decodecaps, encodecaps);