Allocate loop restoration buffers conditionally

The buffers required for loop restoration search and filtering are
allocated and initialized only when loop restoration is used.

BUG=aomedia:2963

Change-Id: Id9af97d706519a13686b9331933c9365bf2e5f08
(cherry picked from commit f053a0a2b5bf2dfe52d24fc3ffc6b3a070551cfd)

av1/encoder/encoder.c

diff --git a/av1/encoder/encoder.c b/av1/encoder/encoder.c
index 160f186..5b350aa 100644
--- a/av1/encoder/encoder.c
+++ b/av1/encoder/encoder.c
@@ -1884,6 +1884,7 @@
   }
 }
 
+#if !CONFIG_REALTIME_ONLY
 #define COUPLED_CHROMA_FROM_LUMA_RESTORATION 0
 static void set_restoration_unit_size(int width, int height, int sx, int sy,
                                       RestorationInfo *rst) {
@@ -1904,6 +1905,7 @@
   rst[1].restoration_unit_size = rst[0].restoration_unit_size >> s;
   rst[2].restoration_unit_size = rst[1].restoration_unit_size;
 }
+#endif
 
 static void init_ref_frame_bufs(AV1_COMP *cpi) {
   AV1_COMMON *const cm = &cpi->common;
@@ -2052,16 +2054,21 @@
     aom_internal_error(&cm->error, AOM_CODEC_MEM_ERROR,
                        "Failed to allocate frame buffer");
 
-  const int frame_width = cm->superres_upscaled_width;
-  const int frame_height = cm->superres_upscaled_height;
-  set_restoration_unit_size(frame_width, frame_height,
-                            seq_params->subsampling_x,
-                            seq_params->subsampling_y, cm->rst_info);
-  for (int i = 0; i < num_planes; ++i)
-    cm->rst_info[i].frame_restoration_type = RESTORE_NONE;
-
 #if !CONFIG_REALTIME_ONLY
-  av1_alloc_restoration_buffers(cm);
+  const int use_restoration = cm->seq_params.enable_restoration &&
+                              !cm->features.all_lossless &&
+                              !cm->tiles.large_scale;
+  if (use_restoration) {
+    const int frame_width = cm->superres_upscaled_width;
+    const int frame_height = cm->superres_upscaled_height;
+    set_restoration_unit_size(frame_width, frame_height,
+                              seq_params->subsampling_x,
+                              seq_params->subsampling_y, cm->rst_info);
+    for (int i = 0; i < num_planes; ++i)
+      cm->rst_info[i].frame_restoration_type = RESTORE_NONE;
+
+    av1_alloc_restoration_buffers(cm);
+  }
 #endif
   if (!is_stat_generation_stage(cpi)) alloc_util_frame_buffers(cpi);
   init_motion_estimation(cpi);

av1/encoder/encoder_alloc.h

diff --git a/av1/encoder/encoder_alloc.h b/av1/encoder/encoder_alloc.h
index cdb5e1e..15f4ac9 100644
--- a/av1/encoder/encoder_alloc.h
+++ b/av1/encoder/encoder_alloc.h
@@ -383,13 +383,20 @@
     aom_internal_error(&cm->error, AOM_CODEC_MEM_ERROR,
                        "Failed to allocate last frame buffer");
 
-  if (aom_realloc_frame_buffer(
-          &cpi->trial_frame_rst, cm->superres_upscaled_width,
-          cm->superres_upscaled_height, seq_params->subsampling_x,
-          seq_params->subsampling_y, seq_params->use_highbitdepth,
-          AOM_RESTORATION_FRAME_BORDER, byte_alignment, NULL, NULL, NULL))
-    aom_internal_error(&cm->error, AOM_CODEC_MEM_ERROR,
-                       "Failed to allocate trial restored frame buffer");
+  // The frame buffer trial_frame_rst is used during loop restoration filter
+  // search. Hence it is allocated only when loop restoration is used.
+  const int use_restoration = cm->seq_params.enable_restoration &&
+                              !cm->features.all_lossless &&
+                              !cm->tiles.large_scale;
+  if (use_restoration) {
+    if (aom_realloc_frame_buffer(
+            &cpi->trial_frame_rst, cm->superres_upscaled_width,
+            cm->superres_upscaled_height, seq_params->subsampling_x,
+            seq_params->subsampling_y, seq_params->use_highbitdepth,
+            AOM_RESTORATION_FRAME_BORDER, byte_alignment, NULL, NULL, NULL))
+      aom_internal_error(&cm->error, AOM_CODEC_MEM_ERROR,
+                         "Failed to allocate trial restored frame buffer");
+  }
 
   if (aom_realloc_frame_buffer(
           &cpi->scaled_source, cm->width, cm->height, seq_params->subsampling_x,