vaapisink: retain VA surface until another one is displayed.

Keep VA surface proxy associated with the surface that is currently
being displayed. This makes sure that surface is not released back
to the pool of surfaces free to use for decoding. This is necessary
with VA driver implementations that support rendering to an overlay
pipe. Otherwise, there could be cases where we are decoding into a
surface that is being displayed, hence some flickering.

diff --git a/gst/vaapi/gstvaapisink.c b/gst/vaapi/gstvaapisink.c
index 4611974..cacf087 100644 (file)
--- a/gst/vaapi/gstvaapisink.c
+++ b/gst/vaapi/gstvaapisink.c
@@ -223,6 +223,7 @@ gst_vaapisink_xoverlay_iface_init(GstXOverlayClass *iface)
 static void
 gst_vaapisink_destroy(GstVaapiSink *sink)
 {
+    gst_buffer_replace(&sink->video_buffer, NULL);
     g_clear_object(&sink->texture);
     g_clear_object(&sink->display);
 
@@ -468,6 +469,7 @@ gst_vaapisink_stop(GstBaseSink *base_sink)
 {
     GstVaapiSink * const sink = GST_VAAPISINK(base_sink);
 
+    gst_buffer_replace(&sink->video_buffer, NULL);
     g_clear_object(&sink->window);
     g_clear_object(&sink->display);
 
@@ -772,7 +774,12 @@ gst_vaapisink_show_frame(GstBaseSink *base_sink, GstBuffer *buffer)
         success = FALSE;
         break;
     }
-    return success ? GST_FLOW_OK : GST_FLOW_UNEXPECTED;
+    if (!success)
+        return GST_FLOW_UNEXPECTED;
+
+    /* Retain VA surface until the next one is displayed */
+    gst_buffer_replace(&sink->video_buffer, buffer);
+    return GST_FLOW_OK;
 }
 
 static gboolean
@@ -938,6 +945,7 @@ gst_vaapisink_init(GstVaapiSink *sink)
     sink->window_width   = 0;
     sink->window_height  = 0;
     sink->texture        = NULL;
+    sink->video_buffer   = NULL;
     sink->video_width    = 0;
     sink->video_height   = 0;
     sink->video_par_n    = 1;

diff --git a/gst/vaapi/gstvaapisink.h b/gst/vaapi/gstvaapisink.h
index 5493046..0e8709f 100644 (file)
--- a/gst/vaapi/gstvaapisink.h
+++ b/gst/vaapi/gstvaapisink.h
@@ -74,6 +74,7 @@ struct _GstVaapiSink {
     guint               window_width;
     guint               window_height;
     GstVaapiTexture    *texture;
+    GstBuffer          *video_buffer;
     guint               video_width;
     guint               video_height;
     gint                video_par_n;