commit 54de7d60d699aa65a29c022231a47e937e39fc49
author Arild Fuldseth (arilfuld) <arilfuld@cisco.com> Mon Mar 20 13:07:11 2017 +0100
committer Arild Fuldseth <arild.fuldseth@gmail.com> Wed Mar 22 07:25:18 2017 +0000
tree 8bc5350534539caaf57ec14c75cbdaffffec75ff
parent 6ff6af6194b7a42bf4941c86f70a1290966d2082

Disallow cm->delta_q_present_flag=1 when cm->base_qindex=0.

Delta quant doesn't make sense if the intent is to encode
the frame in lossless mode.

BUG=aomedia:393

Change-Id: Ic26e30267dd3a061d7ee5e980b6950366f06b32f

av1/decoder/decodeframe.c

diff --git a/av1/decoder/decodeframe.c b/av1/decoder/decodeframe.c
index e4a69a8..fd74e07 100644
--- a/av1/decoder/decodeframe.c
+++ b/av1/decoder/decodeframe.c
@@ -4352,7 +4352,7 @@
     }
 
     cm->delta_q_res = 1;
-    if (segment_quantizer_active == 0) {
+    if (segment_quantizer_active == 0 && cm->base_qindex > 0) {
       cm->delta_q_present_flag = aom_rb_read_bit(rb);
     } else {
       cm->delta_q_present_flag = 0;

av1/decoder/decodemv.c

diff --git a/av1/decoder/decodemv.c b/av1/decoder/decodemv.c
index e12f2a4..cc7922a 100644
--- a/av1/decoder/decodemv.c
+++ b/av1/decoder/decodemv.c
@@ -890,6 +890,8 @@
     xd->current_qindex =
         xd->prev_qindex +
         read_delta_qindex(cm, xd, r, mbmi, mi_col, mi_row) * cm->delta_q_res;
+    /* Normative: Clamp to [1,MAXQ] to not interfere with lossless mode */
+    xd->current_qindex = clamp(xd->current_qindex, 1, MAXQ);
     xd->prev_qindex = xd->current_qindex;
   }
 #endif
@@ -2117,6 +2119,8 @@
     xd->current_qindex =
         xd->prev_qindex +
         read_delta_qindex(cm, xd, r, mbmi, mi_col, mi_row) * cm->delta_q_res;
+    /* Normative: Clamp to [1,MAXQ] to not interfere with lossless mode */
+    xd->current_qindex = clamp(xd->current_qindex, 1, MAXQ);
     xd->prev_qindex = xd->current_qindex;
   }
 #endif