commit bc2e01c9d357daf1eda7434538e3d02f241ec528
author Thomas Davies <thdavies@cisco.com> Mon Jul 10 08:58:47 2017 +0100
committer Thomas Davies <thdavies@cisco.com> Mon Jul 10 17:03:41 2017 +0000
tree e2d06a04e8f41b0764c595399569859d8ff10066
parent 84d35995e16095e429edb0ad6c188ba756e0fc14

Clarify comments on kf_y_cdf to explain usage.

BUG=aomedia:630

Change-Id: Idf39c702dfee4fe35f2b0e768cf60f27ed7db08b

av1/common/entropy.c

diff --git a/av1/common/entropy.c b/av1/common/entropy.c
index 2f0309d..98732a8 100644
--- a/av1/common/entropy.c
+++ b/av1/common/entropy.c
@@ -5725,6 +5725,8 @@
 #endif
 #endif  // CONFIG_EXT_INTER
 
+  /* NB: kf_y_cdf is discarded after use, so no need
+     for backwards update */
   AVERAGE_TILE_CDFS(y_mode_cdf)
 
   if (cm->interp_filter == SWITCHABLE) {

av1/common/entropymode.h

diff --git a/av1/common/entropymode.h b/av1/common/entropymode.h
index ab8596e..0f3b65a 100644
--- a/av1/common/entropymode.h
+++ b/av1/common/entropymode.h
@@ -310,8 +310,10 @@
 #endif
   aom_cdf_prob switchable_interp_cdf[SWITCHABLE_FILTER_CONTEXTS]
                                     [CDF_SIZE(SWITCHABLE_FILTERS)];
-  /* Keep track of kf_y_cdf here, as this makes handling
-     multiple copies for adaptation in tiles easier */
+  /* kf_y_cdf is discarded after use, so does not require persistent storage.
+     However, we keep it with the other CDFs in this struct since it needs to
+     be copied to each tile to support parallelism just like the others.
+   */
   aom_cdf_prob kf_y_cdf[INTRA_MODES][INTRA_MODES][CDF_SIZE(INTRA_MODES)];
   aom_cdf_prob tx_size_cdf[MAX_TX_DEPTH][TX_SIZE_CONTEXTS]
                           [CDF_SIZE(MAX_TX_DEPTH + 1)];