gldownload: Micro-optimisation. Don't check output caps on every buffer

The output caps will only change on a set_caps() call, so check if
they contain the SystemMemory feature then and save some
per-buffer CPU.

2 files changed, 16 insertions, 17 deletions

diff --git a/ext/gl/gstgldownloadelement.c b/ext/gl/gstgldownloadelement.c
index 36821df44..153a3c3f9 100644
--- a/ext/gl/gstgldownloadelement.c
+++ b/ext/gl/gstgldownloadelement.c
@@ -94,11 +94,18 @@ static gboolean
 gst_gl_download_element_set_caps (GstBaseTransform * bt, GstCaps * in_caps,
     GstCaps * out_caps)
 {
+  GstGLDownloadElement *dl = GST_GL_DOWNLOAD_ELEMENT (bt);
   GstVideoInfo out_info;
+  GstCapsFeatures *features = NULL;
 
   if (!gst_video_info_from_caps (&out_info, out_caps))
     return FALSE;
 
+  features = gst_caps_get_features (out_caps, 0);
+
+  dl->do_pbo_transfers = (!features || gst_caps_features_contains (features,
+          GST_CAPS_FEATURE_MEMORY_SYSTEM_MEMORY));
+
   return TRUE;
 }
 
@@ -160,31 +167,21 @@ static GstFlowReturn
 gst_gl_download_element_prepare_output_buffer (GstBaseTransform * bt,
     GstBuffer * inbuf, GstBuffer ** outbuf)
 {
-  GstCaps *src_caps = gst_pad_get_current_caps (bt->srcpad);
-  GstCapsFeatures *features = NULL;
+  GstGLDownloadElement *dl = GST_GL_DOWNLOAD_ELEMENT (bt);
   gint i, n;
 
   *outbuf = inbuf;
 
-  if (src_caps)
-    features = gst_caps_get_features (src_caps, 0);
-
-  n = gst_buffer_n_memory (*outbuf);
-  for (i = 0; i < n; i++) {
-    GstMemory *mem = gst_buffer_peek_memory (*outbuf, i);
+  if (dl->do_pbo_transfers) {
+    n = gst_buffer_n_memory (*outbuf);
+    for (i = 0; i < n; i++) {
+      GstMemory *mem = gst_buffer_peek_memory (*outbuf, i);
 
-    if (gst_is_gl_memory (mem)) {
-      if (!features || gst_caps_features_contains (features,
-              GST_CAPS_FEATURE_MEMORY_SYSTEM_MEMORY)) {
-        if (gst_is_gl_memory_pbo (mem))
-          gst_gl_memory_pbo_download_transfer ((GstGLMemoryPBO *) mem);
-      }
+      if (gst_is_gl_memory_pbo (mem))
+        gst_gl_memory_pbo_download_transfer ((GstGLMemoryPBO *) mem);
     }
   }
 
-  if (src_caps)
-    gst_caps_unref (src_caps);
-
   return GST_FLOW_OK;
 }
 
diff --git a/ext/gl/gstgldownloadelement.h b/ext/gl/gstgldownloadelement.h
index eabfeec9a..e7d4ce03a 100644
--- a/ext/gl/gstgldownloadelement.h
+++ b/ext/gl/gstgldownloadelement.h
@@ -43,6 +43,8 @@ struct _GstGLDownloadElement
 {
   /* <private> */
   GstGLBaseFilter  parent;
+
+  gboolean do_pbo_transfers;
 };
 
 struct _GstGLDownloadElementClass