commit e5ae28332c2d07e420b214d0a074a41c6ab4ef53
author Urvang Joshi <urvang@google.com> Fri May 11 13:47:00 2018 -0700
committer Urvang Joshi <urvang@google.com> Tue May 15 01:57:02 2018 +0000
tree 3bd3b60c643c0f0367c1210cb98f91bd66d7592d
parent d2f317c33564da8b4b54a98dfa6726e572dd6d66

[NORMATIVE] Don't transmit skip_mode for intra blk

In particular, when FeatureData[ segment_id ][ SEG_LVL_REF_FRAME ]
== INTRA_FRAME, this is an intra block. So, don't signal skip_mode, but
rather infer that skip_mode is FALSE.

BUG=aomedia:1874

Change-Id: If2c493e418755a41da9b260ebde01cd3837b27f6

av1/encoder/bitstream.c

diff --git a/av1/encoder/bitstream.c b/av1/encoder/bitstream.c
index 394ecfe..cd15d24 100644
--- a/av1/encoder/bitstream.c
+++ b/av1/encoder/bitstream.c
@@ -238,6 +238,12 @@
     assert(!skip_mode);
     return 0;
   }
+  if (segfeature_active(&cm->seg, segment_id, SEG_LVL_REF_FRAME) &&
+      get_segdata(&cm->seg, segment_id, SEG_LVL_REF_FRAME) == INTRA_FRAME) {
+    // This is an intra block, so skip_mode is implicitly 0.
+    assert(!skip_mode);
+    return 0;
+  }
   const int ctx = av1_get_skip_mode_context(xd);
   aom_write_symbol(w, skip_mode, xd->tile_ctx->skip_mode_cdfs[ctx], 2);
   return skip_mode;