plugin: simplify caps feature selection

This patch simplifies the function gst_vaapi_find_preferred_caps_feature().

Instead of intersecting custom caps to find the preferred feature, the peer
caps are traversed in order to find the preferred feature, according to an
ordered feature priority list.

In the case of GLTextureUploadMeta, the colour format is computed using
GstVideoInfo of the selected fixed caps.

https://bugzilla.gnome.org/show_bug.cgi?id=765223

diff --git a/gst/vaapi/gstvaapipluginutil.c b/gst/vaapi/gstvaapipluginutil.c
index cc878e3..c190aff 100644 (file)
--- a/gst/vaapi/gstvaapipluginutil.c
+++ b/gst/vaapi/gstvaapipluginutil.c
@@ -432,55 +432,30 @@ gst_vaapi_video_format_new_template_caps_with_features (GstVideoFormat format,
   return caps;
 }
 
-static GstCaps *
-new_gl_texture_upload_meta_caps (void)
-{
-  return
-      gst_caps_from_string (GST_VIDEO_CAPS_MAKE_WITH_FEATURES
-      (GST_CAPS_FEATURE_META_GST_VIDEO_GL_TEXTURE_UPLOAD_META,
-          "{ RGBA, BGRA }"));
-}
-
 GstVaapiCapsFeature
 gst_vaapi_find_preferred_caps_feature (GstPad * pad, GstVideoFormat format,
     GstVideoFormat * out_format_ptr)
 {
-  GstVaapiCapsFeature feature = GST_VAAPI_CAPS_FEATURE_SYSTEM_MEMORY;
-  guint i, num_structures;
+  GstVaapiCapsFeature feature = GST_VAAPI_CAPS_FEATURE_NOT_NEGOTIATED;
+  guint i, j, num_structures;
   GstCaps *caps = NULL;
-  GstCaps *gl_texture_upload_caps = NULL;
-  GstCaps *sysmem_caps = NULL;
-  GstCaps *vaapi_caps = NULL;
   GstCaps *out_caps, *templ;
   GstVideoFormat out_format;
+  static const guint feature_list[] = { GST_VAAPI_CAPS_FEATURE_VAAPI_SURFACE,
+    GST_VAAPI_CAPS_FEATURE_GL_TEXTURE_UPLOAD_META,
+    GST_VAAPI_CAPS_FEATURE_SYSTEM_MEMORY,
+  };
 
   templ = gst_pad_get_pad_template_caps (pad);
   out_caps = gst_pad_peer_query_caps (pad, templ);
   gst_caps_unref (templ);
-  if (!out_caps) {
-    feature = GST_VAAPI_CAPS_FEATURE_NOT_NEGOTIATED;
+  if (!out_caps)
     goto cleanup;
-  }
 
   out_format = format == GST_VIDEO_FORMAT_ENCODED ?
       GST_VIDEO_FORMAT_NV12 : format;
 
-  gl_texture_upload_caps = new_gl_texture_upload_meta_caps ();
-  if (!gl_texture_upload_caps)
-    goto cleanup;
-
-  vaapi_caps =
-      gst_vaapi_video_format_new_template_caps_with_features (out_format,
-      GST_CAPS_FEATURE_MEMORY_VAAPI_SURFACE);
-  if (!vaapi_caps)
-    goto cleanup;
-
-  sysmem_caps =
-      gst_vaapi_video_format_new_template_caps_with_features (out_format,
-      GST_CAPS_FEATURE_MEMORY_SYSTEM_MEMORY);
-  if (!sysmem_caps)
-    goto cleanup;
-
+  feature = GST_VAAPI_CAPS_FEATURE_SYSTEM_MEMORY;
   num_structures = gst_caps_get_size (out_caps);
   for (i = 0; i < num_structures; i++) {
     GstCapsFeatures *const features = gst_caps_get_features (out_caps, i);
@@ -490,21 +465,19 @@ gst_vaapi_find_preferred_caps_feature (GstPad * pad, GstVideoFormat format,
     if (gst_caps_features_is_any (features))
       continue;
 
+    gst_caps_replace (&caps, NULL);
     caps = gst_caps_new_full (gst_structure_copy (structure), NULL);
     if (!caps)
       continue;
     gst_caps_set_features (caps, 0, gst_caps_features_copy (features));
 
-    if (gst_caps_can_intersect (caps, vaapi_caps) &&
-        feature < GST_VAAPI_CAPS_FEATURE_VAAPI_SURFACE)
-      feature = GST_VAAPI_CAPS_FEATURE_VAAPI_SURFACE;
-    else if (gst_caps_can_intersect (caps, gl_texture_upload_caps) &&
-        feature < GST_VAAPI_CAPS_FEATURE_GL_TEXTURE_UPLOAD_META)
-      feature = GST_VAAPI_CAPS_FEATURE_GL_TEXTURE_UPLOAD_META;
-    else if (gst_caps_can_intersect (caps, sysmem_caps) &&
-        feature < GST_VAAPI_CAPS_FEATURE_SYSTEM_MEMORY)
-      feature = GST_VAAPI_CAPS_FEATURE_SYSTEM_MEMORY;
-    gst_caps_replace (&caps, NULL);
+    for (j = 0; j < G_N_ELEMENTS (feature_list); j++) {
+      if (gst_vaapi_caps_feature_contains (caps, feature_list[j])
+          && feature < feature_list[j]) {
+        feature = feature_list[j];
+        break;
+      }
+    }
 
     /* Stop at the first match, the caps should already be sorted out
        by preference order from downstream elements */
@@ -512,35 +485,25 @@ gst_vaapi_find_preferred_caps_feature (GstPad * pad, GstVideoFormat format,
       break;
   }
 
+  if (!caps)
+    goto cleanup;
+
   if (out_format_ptr) {
     if (feature == GST_VAAPI_CAPS_FEATURE_GL_TEXTURE_UPLOAD_META) {
-      GstStructure *structure;
-      gchar *format_str;
-      out_format = GST_VIDEO_FORMAT_UNKNOWN;
-      do {
-        caps = gst_caps_intersect_full (out_caps, gl_texture_upload_caps,
-            GST_CAPS_INTERSECT_FIRST);
-        if (!caps)
-          break;
-        structure = gst_caps_get_structure (caps, 0);
-        if (!structure)
-          break;
-        if (!gst_structure_get (structure, "format", G_TYPE_STRING,
-                &format_str, NULL))
-          break;
-        out_format = gst_video_format_from_string (format_str);
-        g_free (format_str);
-      } while (0);
-      if (!out_format)
+      GstVideoInfo vinfo;
+      if (!gst_caps_is_fixed (caps))
+        caps = gst_caps_fixate (caps);
+
+      gst_video_info_from_caps (&vinfo, caps);
+      out_format = GST_VIDEO_INFO_FORMAT (&vinfo);
+
+      if (out_format == GST_VIDEO_FORMAT_UNKNOWN)
         goto cleanup;
     }
     *out_format_ptr = out_format;
   }
 
 cleanup:
-  gst_caps_replace (&gl_texture_upload_caps, NULL);
-  gst_caps_replace (&sysmem_caps, NULL);
-  gst_caps_replace (&vaapi_caps, NULL);
   gst_caps_replace (&caps, NULL);
   gst_caps_replace (&out_caps, NULL);
   return feature;