From 446aa9acf8eb2b142121e7b3be65fd35df324724 Mon Sep 17 00:00:00 2001
From: Gwenole Beauchesne <gwenole.beauchesne@intel.com>
Date: Sat, 3 May 2014 15:56:51 +0200
Subject: [PATCH] context: allow dynamic growth of VA surfaces pool.

Add support for dynamic growth of the VA surfaces pool. For decoding,
this implies the recreation of the underlying VA context, as per the
requirement from VA-API. Besides, only increases are supported, not
shrinks.
---
 gst-libs/gst/vaapi/gstvaapicontext.c | 55 ++++++++++++++++++----------
 1 file changed, 36 insertions(+), 19 deletions(-)

diff --git a/gst-libs/gst/vaapi/gstvaapicontext.c b/gst-libs/gst/vaapi/gstvaapicontext.c
index 27efdd9ad2..185ed7fdb8 100644
--- a/gst-libs/gst/vaapi/gstvaapicontext.c
+++ b/gst-libs/gst/vaapi/gstvaapicontext.c
@@ -47,6 +47,9 @@
 /* Define default VA surface chroma format to YUV 4:2:0 */
 #define DEFAULT_CHROMA_TYPE (GST_VAAPI_CHROMA_TYPE_YUV420)
 
+/* Number of scratch surfaces beyond those used as reference */
+#define SCRATCH_SURFACES_COUNT (4)
+
 static void
 unref_surface_cb (GstVaapiSurface * surface)
 {
@@ -105,16 +108,34 @@ context_destroy (GstVaapiContext * context)
   }
 }
 
+static gboolean
+context_ensure_surfaces (GstVaapiContext * context)
+{
+  const GstVaapiContextInfo *const cip = &context->info;
+  const guint num_surfaces = cip->ref_frames + SCRATCH_SURFACES_COUNT;
+  GstVaapiSurface *surface;
+  guint i;
+
+  for (i = context->surfaces->len; i < num_surfaces; i++) {
+    surface = gst_vaapi_surface_new (GST_VAAPI_OBJECT_DISPLAY (context),
+        cip->chroma_type, cip->width, cip->height);
+    if (!surface)
+      return FALSE;
+    gst_vaapi_surface_set_parent_context (surface, context);
+    g_ptr_array_add (context->surfaces, surface);
+    if (!gst_vaapi_video_pool_add_object (context->surfaces_pool, surface))
+      return FALSE;
+  }
+  gst_vaapi_video_pool_set_capacity (context->surfaces_pool, num_surfaces);
+  return TRUE;
+}
+
 static gboolean
 context_create_surfaces (GstVaapiContext * context)
 {
   const GstVaapiContextInfo *const cip = &context->info;
   GstVideoInfo vi;
-  GstVaapiSurface *surface;
-  guint i, num_surfaces;
-
-  /* Number of scratch surfaces beyond those used as reference */
-  const guint SCRATCH_SURFACES_COUNT = 4;
+  guint num_surfaces;
 
   if (!gst_vaapi_context_overlay_reset (context))
     return FALSE;
@@ -135,19 +156,7 @@ context_create_surfaces (GstVaapiContext * context)
     if (!context->surfaces_pool)
       return FALSE;
   }
-  gst_vaapi_video_pool_set_capacity (context->surfaces_pool, num_surfaces);
-
-  for (i = context->surfaces->len; i < num_surfaces; i++) {
-    surface = gst_vaapi_surface_new (GST_VAAPI_OBJECT_DISPLAY (context),
-        cip->chroma_type, cip->width, cip->height);
-    if (!surface)
-      return FALSE;
-    gst_vaapi_surface_set_parent_context (surface, context);
-    g_ptr_array_add (context->surfaces, surface);
-    if (!gst_vaapi_video_pool_add_object (context->surfaces_pool, surface))
-      return FALSE;
-  }
-  return TRUE;
+  return context_ensure_surfaces (context);
 }
 
 static gboolean
@@ -370,6 +379,7 @@ gst_vaapi_context_reset (GstVaapiContext * context,
 {
   GstVaapiContextInfo *const cip = &context->info;
   gboolean reset_surfaces = FALSE, reset_config = FALSE;
+  gboolean grow_surfaces = FALSE;
   GstVaapiChromaType chroma_type;
 
   chroma_type = new_cip->chroma_type ? new_cip->chroma_type :
@@ -392,6 +402,11 @@ gst_vaapi_context_reset (GstVaapiContext * context,
     reset_config = TRUE;
   }
 
+  if (cip->ref_frames < new_cip->ref_frames) {
+    cip->ref_frames = new_cip->ref_frames;
+    grow_surfaces = TRUE;
+  }
+
   if (cip->usage != new_cip->usage) {
     cip->usage = new_cip->usage;
     reset_config = TRUE;
@@ -400,7 +415,7 @@ gst_vaapi_context_reset (GstVaapiContext * context,
     if (context_update_config_encoder (context, &new_cip->config.encoder))
       reset_config = TRUE;
   } else if (new_cip->usage == GST_VAAPI_CONTEXT_USAGE_DECODE) {
-    if (reset_surfaces)
+    if (reset_surfaces || grow_surfaces)
       reset_config = TRUE;
   }
 
@@ -411,6 +426,8 @@ gst_vaapi_context_reset (GstVaapiContext * context,
 
   if (reset_surfaces && !context_create_surfaces (context))
     return FALSE;
+  else if (grow_surfaces && !context_ensure_surfaces (context))
+    return FALSE;
   if (reset_config && !context_create (context))
     return FALSE;
   return TRUE;