Make update_map/temporal_update fields implicit for keyframes.

These frame types cannot make bitstream parsing depend on previous
frames, so the hypothetical combinations of e.g. keyframe=1 and
update_map=0 or keyframe=1 and temporal_update=1 are non-sensical.
Therefore, make it impossible to code such combinations in the vp10
bitstream header.

See issue 1044.

Change-Id: I3f0a83d5c7e3989541a469a909471424a285239d

1 files changed, 13 insertions, 17 deletions

diff --git a/vp10/decoder/decodemv.c b/vp10/decoder/decodemv.c
index 681e02f39..b190f734c 100644
--- a/vp10/decoder/decodemv.c
+++ b/vp10/decoder/decodemv.c
@@ -116,18 +116,6 @@ static void set_segment_id(VP10_COMMON *cm, int mi_offset,
       cm->current_frame_seg_map[mi_offset + y * cm->mi_cols + x] = segment_id;
 }
 
-static void copy_segment_id(const VP10_COMMON *cm,
-                           const uint8_t *last_segment_ids,
-                           uint8_t *current_segment_ids,
-                           int mi_offset, int x_mis, int y_mis) {
-  int x, y;
-
-  for (y = 0; y < y_mis; y++)
-    for (x = 0; x < x_mis; x++)
-      current_segment_ids[mi_offset + y * cm->mi_cols + x] =  last_segment_ids ?
-          last_segment_ids[mi_offset + y * cm->mi_cols + x] : 0;
-}
-
 static int read_intra_segment_id(VP10_COMMON *const cm, int mi_offset,
                                  int x_mis, int y_mis,
                                  vpx_reader *r) {
@@ -137,17 +125,25 @@ static int read_intra_segment_id(VP10_COMMON *const cm, int mi_offset,
   if (!seg->enabled)
     return 0;  // Default for disabled segmentation
 
-  if (!seg->update_map) {
-    copy_segment_id(cm, cm->last_frame_seg_map, cm->current_frame_seg_map,
-                    mi_offset, x_mis, y_mis);
-    return 0;
-  }
+  assert(seg->update_map && !seg->temporal_update);
 
   segment_id = read_segment_id(r, seg);
   set_segment_id(cm, mi_offset, x_mis, y_mis, segment_id);
   return segment_id;
 }
 
+static void copy_segment_id(const VP10_COMMON *cm,
+                           const uint8_t *last_segment_ids,
+                           uint8_t *current_segment_ids,
+                           int mi_offset, int x_mis, int y_mis) {
+  int x, y;
+
+  for (y = 0; y < y_mis; y++)
+    for (x = 0; x < x_mis; x++)
+      current_segment_ids[mi_offset + y * cm->mi_cols + x] =  last_segment_ids ?
+          last_segment_ids[mi_offset + y * cm->mi_cols + x] : 0;
+}
+
 static int read_inter_segment_id(VP10_COMMON *const cm, MACROBLOCKD *const xd,
                                  int mi_row, int mi_col, vpx_reader *r) {
   struct segmentation *const seg = &cm->seg;