From: Dmitry Kovalev <dkovalev@google.com>
Date: Fri, 8 Nov 2013 20:44:56 +0000 (-0800)
Subject: Optimizing set_contexts() function.
X-Git-Tag: v1.3.0~30^2
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=22a001988bffbd6ba023d1522460d380bf65baa5;p=libvpx

Optimizing set_contexts() function.

Inlining set_contexts_on_border() into set_contexts(). The only difference
is the additional check that "has_eob != 0" in addition to
"xd->mb_to_right_edge < 0" and "xd->mb_to_right_edge < 0". If has_eob == 0
then memset does the right thing and works faster.

Change-Id: I5206f767d729f758b14c667592b7034df4837d0e
---

diff --git a/vp9/common/vp9_blockd.h b/vp9/common/vp9_blockd.h
index d0d485272..5c1fa5cfb 100644
--- a/vp9/common/vp9_blockd.h
+++ b/vp9/common/vp9_blockd.h
@@ -457,57 +457,46 @@ static void extend_for_intra(MACROBLOCKD *xd, BLOCK_SIZE plane_bsize,
     }
   }
 }
-static void set_contexts_on_border(const MACROBLOCKD *xd,
-                                   struct macroblockd_plane *pd,
-                                   BLOCK_SIZE plane_bsize,
-                                   int tx_size_in_blocks, int has_eob,
-                                   int aoff, int loff,
-                                   ENTROPY_CONTEXT *A, ENTROPY_CONTEXT *L) {
-  int mi_blocks_wide = num_4x4_blocks_wide_lookup[plane_bsize];
-  int mi_blocks_high = num_4x4_blocks_high_lookup[plane_bsize];
-  int above_contexts = tx_size_in_blocks;
-  int left_contexts = tx_size_in_blocks;
-  int pt;
-
-  // xd->mb_to_right_edge is in units of pixels * 8.  This converts
-  // it to 4x4 block sizes.
-  if (xd->mb_to_right_edge < 0)
-    mi_blocks_wide += (xd->mb_to_right_edge >> (5 + pd->subsampling_x));
-
-  if (xd->mb_to_bottom_edge < 0)
-    mi_blocks_high += (xd->mb_to_bottom_edge >> (5 + pd->subsampling_y));
-
-  // this code attempts to avoid copying into contexts that are outside
-  // our border.  Any blocks that do are set to 0...
-  if (above_contexts + aoff > mi_blocks_wide)
-    above_contexts = mi_blocks_wide - aoff;
-
-  if (left_contexts + loff > mi_blocks_high)
-    left_contexts = mi_blocks_high - loff;
-
-  for (pt = 0; pt < above_contexts; pt++)
-    A[pt] = has_eob;
-  for (pt = above_contexts; pt < tx_size_in_blocks; pt++)
-    A[pt] = 0;
-  for (pt = 0; pt < left_contexts; pt++)
-    L[pt] = has_eob;
-  for (pt = left_contexts; pt < tx_size_in_blocks; pt++)
-    L[pt] = 0;
-}
 
 static void set_contexts(const MACROBLOCKD *xd, struct macroblockd_plane *pd,
                          BLOCK_SIZE plane_bsize, TX_SIZE tx_size,
                          int has_eob, int aoff, int loff) {
-  ENTROPY_CONTEXT *const A = pd->above_context + aoff;
-  ENTROPY_CONTEXT *const L = pd->left_context + loff;
+  ENTROPY_CONTEXT *const a = pd->above_context + aoff;
+  ENTROPY_CONTEXT *const l = pd->left_context + loff;
   const int tx_size_in_blocks = 1 << tx_size;
 
-  if (xd->mb_to_right_edge < 0 || xd->mb_to_bottom_edge < 0) {
-    set_contexts_on_border(xd, pd, plane_bsize, tx_size_in_blocks, has_eob,
-                           aoff, loff, A, L);
+  // above
+  if (has_eob && xd->mb_to_right_edge < 0) {
+    int i;
+    const int blocks_wide = num_4x4_blocks_wide_lookup[plane_bsize] +
+                            (xd->mb_to_right_edge >> (5 + pd->subsampling_x));
+    int above_contexts = tx_size_in_blocks;
+    if (above_contexts + aoff > blocks_wide)
+      above_contexts = blocks_wide - aoff;
+
+    for (i = 0; i < above_contexts; ++i)
+      a[i] = has_eob;
+    for (i = above_contexts; i < tx_size_in_blocks; ++i)
+      a[i] = 0;
+  } else {
+    vpx_memset(a, has_eob, sizeof(ENTROPY_CONTEXT) * tx_size_in_blocks);
+  }
+
+  // left
+  if (has_eob && xd->mb_to_bottom_edge < 0) {
+    int i;
+    const int blocks_high = num_4x4_blocks_high_lookup[plane_bsize] +
+                            (xd->mb_to_bottom_edge >> (5 + pd->subsampling_y));
+    int left_contexts = tx_size_in_blocks;
+    if (left_contexts + loff > blocks_high)
+      left_contexts = blocks_high - loff;
+
+    for (i = 0; i < left_contexts; ++i)
+      l[i] = has_eob;
+    for (i = left_contexts; i < tx_size_in_blocks; ++i)
+      l[i] = 0;
   } else {
-    vpx_memset(A, has_eob, sizeof(ENTROPY_CONTEXT) * tx_size_in_blocks);
-    vpx_memset(L, has_eob, sizeof(ENTROPY_CONTEXT) * tx_size_in_blocks);
+    vpx_memset(l, has_eob, sizeof(ENTROPY_CONTEXT) * tx_size_in_blocks);
   }
 }