va: filter, deinterlace, vpp: Add gst_va_buffer_get_surface_flags().

Add a helper function to get, from GstVideoInfo and GstBuffers flags,
the VA interlace surface flags. This is used currently by vainterlace
element, but it will be used in vapostproc too if it can process
interlaced frames.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/1109>

subprojects/gst-plugins-bad/sys/va/gstvadeinterlace.c

@@ -396,32 +396,7 @@ gst_va_deinterlace_transform (GstBaseTransform * trans, GstBuffer * inbuf,
   g_assert (self->curr_field == FIRST_FIELD
       || self->curr_field == SECOND_FIELD);
 
-  surface_flags = 0;
+  surface_flags = gst_va_buffer_get_surface_flags (inbuf, info);
-  if (GST_VIDEO_INFO_INTERLACE_MODE (info) == GST_VIDEO_INTERLACE_MODE_MIXED
-      || (GST_VIDEO_INFO_INTERLACE_MODE (info) ==
-          GST_VIDEO_INTERLACE_MODE_INTERLEAVED
-          && GST_VIDEO_INFO_FIELD_ORDER (info) ==
-          GST_VIDEO_FIELD_ORDER_UNKNOWN)) {
-    if (GST_BUFFER_FLAG_IS_SET (inbuf, GST_VIDEO_BUFFER_FLAG_INTERLACED)) {
-      if (GST_BUFFER_FLAG_IS_SET (inbuf, GST_VIDEO_BUFFER_FLAG_TFF)) {
-        surface_flags = VA_TOP_FIELD_FIRST;
-      } else {
-        surface_flags = VA_BOTTOM_FIELD_FIRST;
-      }
-    } else {
-      /* complete frame? do it twice */
-      surface_flags = VA_FRAME_PICTURE;
-    }
-  } else if (GST_VIDEO_INFO_FIELD_ORDER (info) ==
-      GST_VIDEO_FIELD_ORDER_BOTTOM_FIELD_FIRST) {
-    surface_flags = VA_BOTTOM_FIELD_FIRST;
-  } else if (GST_VIDEO_INFO_FIELD_ORDER (info) ==
-      GST_VIDEO_FIELD_ORDER_TOP_FIELD_FIRST) {
-    surface_flags = VA_TOP_FIELD_FIRST;
-  } else {
-    g_assert_not_reached ();
-  }
-
   if (surface_flags != VA_FRAME_PICTURE)
     _set_field (self, &surface_flags);
 

subprojects/gst-plugins-bad/sys/va/gstvafilter.c

@@ -1695,3 +1695,43 @@ fail_end_pic:
     goto bail;
   }
 }
+
+/**
+ * gst_va_buffer_get_surface_flags:
+ * @buffer: the #GstBuffer to check.
+ * @info: the #GstVideoInfo with info.
+ *
+ * Gets the surface flags, related with interlace given @buffer and
+ * @info.
+ *
+ * Returns: VA surface flags.
+ */
+guint32
+gst_va_buffer_get_surface_flags (GstBuffer * buffer, GstVideoInfo * info)
+{
+  guint32 surface_flags = 0;
+
+  if (GST_VIDEO_INFO_INTERLACE_MODE (info) == GST_VIDEO_INTERLACE_MODE_MIXED
+      || (GST_VIDEO_INFO_INTERLACE_MODE (info) ==
+          GST_VIDEO_INTERLACE_MODE_INTERLEAVED
+          && GST_VIDEO_INFO_FIELD_ORDER (info) ==
+          GST_VIDEO_FIELD_ORDER_UNKNOWN)) {
+    if (GST_BUFFER_FLAG_IS_SET (buffer, GST_VIDEO_BUFFER_FLAG_INTERLACED)) {
+      if (GST_BUFFER_FLAG_IS_SET (buffer, GST_VIDEO_BUFFER_FLAG_TFF)) {
+        surface_flags = VA_TOP_FIELD_FIRST;
+      } else {
+        surface_flags = VA_BOTTOM_FIELD_FIRST;
+      }
+    } else {
+      surface_flags = VA_FRAME_PICTURE;
+    }
+  } else if (GST_VIDEO_INFO_FIELD_ORDER (info) ==
+      GST_VIDEO_FIELD_ORDER_BOTTOM_FIELD_FIRST) {
+    surface_flags = VA_BOTTOM_FIELD_FIRST;
+  } else if (GST_VIDEO_INFO_FIELD_ORDER (info) ==
+      GST_VIDEO_FIELD_ORDER_TOP_FIELD_FIRST) {
+    surface_flags = VA_TOP_FIELD_FIRST;
+  }
+
+  return surface_flags;
+}

subprojects/gst-plugins-bad/sys/va/gstvafilter.h

@@ -110,4 +110,7 @@ gboolean              gst_va_filter_process               (GstVaFilter * self,
                                                            GstVaSample * src,
                                                            GstVaSample * dest);
 
+guint32               gst_va_buffer_get_surface_flags     (GstBuffer * buffer,
+                                                           GstVideoInfo * info);
+
 G_END_DECLS

subprojects/gst-plugins-bad/sys/va/gstvavpp.c

@@ -651,10 +651,12 @@ gst_va_vpp_transform (GstBaseTransform * trans, GstBuffer * inbuf,
   /* *INDENT-OFF* */
   src = (GstVaSample) {
     .buffer = buf,
+    .flags = gst_va_buffer_get_surface_flags (buf, &btrans->in_info),
   };
 
   dst = (GstVaSample) {
     .buffer = outbuf,
+    .flags = gst_va_buffer_get_surface_flags (outbuf, &btrans->out_info),
   };
   /* *INDENT-ON* */