shithub: libvpx

Download patch

ref: ba54a886c3f3ba05db5dd30d46761e32daa9e258
parent: c1486f0efa70fdc1cebf1b065e73211d8f689b60
author: Dmitry Kovalev <dkovalev@google.com>
date: Wed Mar 12 08:32:09 EDT 2014 

Speeding up reading of intra block modes.

Reimplementing sub8x8-reading of intra block modes in
read_intra_frame_mode_info() and read_intra_block_mode_info(). Code looks
more readable as well.

Change-Id: Ia42fc7d0dad708bc0c7a8bff1f8b37809b843f40


--- a/vp9/decoder/vp9_decodemv.c
+++ b/vp9/decoder/vp9_decodemv.c
@@ -166,6 +166,7 @@
   const MODE_INFO *above_mi = xd->mi_8x8[-cm->mode_info_stride];
   const MODE_INFO *left_mi  = xd->left_available ? xd->mi_8x8[-1] : NULL;
   const BLOCK_SIZE bsize = mbmi->sb_type;
+  int i;
 
   mbmi->segment_id = read_intra_segment_id(cm, xd, mi_row, mi_col, r);
   mbmi->skip = read_skip(cm, xd, mbmi->segment_id, r);
@@ -173,28 +174,28 @@
   mbmi->ref_frame[0] = INTRA_FRAME;
   mbmi->ref_frame[1] = NONE;
 
-  if (bsize >= BLOCK_8X8) {
-    mbmi->mode = read_intra_mode(r, get_y_mode_probs(mi, above_mi, left_mi, 0));
-  } else {
-    // Only 4x4, 4x8, 8x4 blocks
-    const int num_4x4_w = num_4x4_blocks_wide_lookup[bsize];  // 1 or 2
-    const int num_4x4_h = num_4x4_blocks_high_lookup[bsize];  // 1 or 2
-    int idx, idy;
-
-    for (idy = 0; idy < 2; idy += num_4x4_h) {
-      for (idx = 0; idx < 2; idx += num_4x4_w) {
-        const int block = idy * 2 + idx;
-        const MB_PREDICTION_MODE mode =
-            read_intra_mode(r, get_y_mode_probs(mi, above_mi, left_mi, block));
-        mi->bmi[block].as_mode = mode;
-        if (num_4x4_h == 2)
-          mi->bmi[block + 2].as_mode = mode;
-        if (num_4x4_w == 2)
-          mi->bmi[block + 1].as_mode = mode;
-      }
-    }
-
-    mbmi->mode = mi->bmi[3].as_mode;
+  switch (bsize) {
+    case BLOCK_4X4:
+      for (i = 0; i < 4; ++i)
+        mi->bmi[i].as_mode =
+            read_intra_mode(r, get_y_mode_probs(mi, above_mi, left_mi, i));
+      mbmi->mode = mi->bmi[3].as_mode;
+      break;
+    case BLOCK_4X8:
+      mi->bmi[0].as_mode = mi->bmi[2].as_mode =
+          read_intra_mode(r, get_y_mode_probs(mi, above_mi, left_mi, 0));
+      mi->bmi[1].as_mode = mi->bmi[3].as_mode = mbmi->mode =
+          read_intra_mode(r, get_y_mode_probs(mi, above_mi, left_mi, 1));
+      break;
+    case BLOCK_8X4:
+      mi->bmi[0].as_mode = mi->bmi[1].as_mode =
+          read_intra_mode(r, get_y_mode_probs(mi, above_mi, left_mi, 0));
+      mi->bmi[2].as_mode = mi->bmi[3].as_mode = mbmi->mode =
+          read_intra_mode(r, get_y_mode_probs(mi, above_mi, left_mi, 2));
+      break;
+    default:
+      mbmi->mode = read_intra_mode(r,
+                                   get_y_mode_probs(mi, above_mi, left_mi, 0));
   }
 
   mbmi->uv_mode = read_intra_mode(r, vp9_kf_uv_mode_prob[mbmi->mode]);
@@ -324,30 +325,29 @@
                                        vp9_reader *r) {
   MB_MODE_INFO *const mbmi = &mi->mbmi;
   const BLOCK_SIZE bsize = mi->mbmi.sb_type;
+  int i;
 
   mbmi->ref_frame[0] = INTRA_FRAME;
   mbmi->ref_frame[1] = NONE;
 
-  if (bsize >= BLOCK_8X8) {
-    mbmi->mode = read_intra_mode_y(cm, r, size_group_lookup[bsize]);
-  } else {
-     // Only 4x4, 4x8, 8x4 blocks
-     const int num_4x4_w = num_4x4_blocks_wide_lookup[bsize];  // 1 or 2
-     const int num_4x4_h = num_4x4_blocks_high_lookup[bsize];  // 1 or 2
-     int idx, idy;
-
-     for (idy = 0; idy < 2; idy += num_4x4_h) {
-       for (idx = 0; idx < 2; idx += num_4x4_w) {
-         const int ib = idy * 2 + idx;
-         const int b_mode = read_intra_mode_y(cm, r, 0);
-         mi->bmi[ib].as_mode = b_mode;
-         if (num_4x4_h == 2)
-           mi->bmi[ib + 2].as_mode = b_mode;
-         if (num_4x4_w == 2)
-           mi->bmi[ib + 1].as_mode = b_mode;
-      }
-    }
-    mbmi->mode = mi->bmi[3].as_mode;
+  switch (bsize) {
+    case BLOCK_4X4:
+      for (i = 0; i < 4; ++i)
+        mi->bmi[i].as_mode = read_intra_mode_y(cm, r, 0);
+      mbmi->mode = mi->bmi[3].as_mode;
+      break;
+    case BLOCK_4X8:
+      mi->bmi[0].as_mode = mi->bmi[2].as_mode = read_intra_mode_y(cm, r, 0);
+      mi->bmi[1].as_mode = mi->bmi[3].as_mode = mbmi->mode =
+          read_intra_mode_y(cm, r, 0);
+      break;
+    case BLOCK_8X4:
+      mi->bmi[0].as_mode = mi->bmi[1].as_mode = read_intra_mode_y(cm, r, 0);
+      mi->bmi[2].as_mode = mi->bmi[3].as_mode = mbmi->mode =
+          read_intra_mode_y(cm, r, 0);
+      break;
+    default:
+      mbmi->mode = read_intra_mode_y(cm, r, size_group_lookup[bsize]);
   }
 
   mbmi->uv_mode = read_intra_mode_uv(cm, r, mbmi->mode);
-- 
⑨