Implement intra-coded frames

Implements ability to signal and decode frames that are
encoded using only intra coding modes. Only the decode
side has been implemented here.

Change-Id: I53ac6a8d90422cd08ba389e5236e15b45f9e93de

2 files changed, 11 insertions, 10 deletions

diff --git a/vp9/decoder/vp9_decodemv.c b/vp9/decoder/vp9_decodemv.c
index 99902d92a..477296b31 100644
--- a/vp9/decoder/vp9_decodemv.c
+++ b/vp9/decoder/vp9_decodemv.c
@@ -337,7 +337,7 @@ static INLINE COMPPREDMODE_TYPE read_comp_pred_mode(vp9_reader *r) {
 static void mb_mode_mv_init(VP9D_COMP *pbi, vp9_reader *r) {
   VP9_COMMON *const cm = &pbi->common;
 
-  if (cm->frame_type != KEY_FRAME) {
+  if ((cm->frame_type != KEY_FRAME) && (!cm->intra_only)) {
     nmv_context *const nmvc = &pbi->common.fc.nmvc;
     MACROBLOCKD *const xd = &pbi->mb;
     int i, j;
@@ -816,7 +816,7 @@ void vp9_decode_mb_mode_mv(VP9D_COMP* const pbi,
   MODE_INFO *mi = xd->mode_info_context;
   MB_MODE_INFO *const mbmi = &mi->mbmi;
 
-  if (cm->frame_type == KEY_FRAME) {
+  if ((cm->frame_type == KEY_FRAME) || cm->intra_only) {
     kfread_modes(pbi, mi, mi_row, mi_col, r);
   } else {
     read_mb_modes_mv(pbi, mi, &mi->mbmi, mi_row, mi_col, r);
diff --git a/vp9/decoder/vp9_decodframe.c b/vp9/decoder/vp9_decodframe.c
index 1bc7696fb..21ac3987f 100644
--- a/vp9/decoder/vp9_decodframe.c
+++ b/vp9/decoder/vp9_decodframe.c
@@ -308,7 +308,7 @@ static void decode_atom(VP9D_COMP *pbi, MACROBLOCKD *xd,
 
   assert(mbmi->ref_frame[0] != INTRA_FRAME);
 
-  if (pbi->common.frame_type != KEY_FRAME)
+  if ((pbi->common.frame_type != KEY_FRAME) && (!pbi->common.intra_only))
     vp9_setup_interp_filters(xd, mbmi->interp_filter, &pbi->common);
 
   // prediction
@@ -1062,8 +1062,6 @@ static size_t read_uncompressed_header(VP9D_COMP *pbi,
       }
     }
 
-    vp9_setup_past_independence(cm, xd);
-
     pbi->refresh_frame_flags = (1 << NUM_REF_FRAMES) - 1;
 
     for (i = 0; i < ALLOWED_REFS_PER_FRAME; ++i)
@@ -1073,11 +1071,12 @@ static size_t read_uncompressed_header(VP9D_COMP *pbi,
   } else {
     cm->intra_only = cm->show_frame ? 0 : vp9_rb_read_bit(rb);
 
-    if (cm->error_resilient_mode)
-      vp9_setup_past_independence(cm, xd);
+    cm->reset_frame_context = cm->error_resilient_mode ?
+        0 : vp9_rb_read_literal(rb, 2);
 
     if (cm->intra_only) {
       check_sync_code(cm, rb);
+
       pbi->refresh_frame_flags = vp9_rb_read_literal(rb, NUM_REF_FRAMES);
       setup_frame_size(pbi, rb);
     } else {
@@ -1102,17 +1101,19 @@ static size_t read_uncompressed_header(VP9D_COMP *pbi,
   }
 
   if (!cm->error_resilient_mode) {
-    cm->reset_frame_context = vp9_rb_read_literal(rb, 2);
     cm->refresh_frame_context = vp9_rb_read_bit(rb);
     cm->frame_parallel_decoding_mode = vp9_rb_read_bit(rb);
   } else {
-    cm->reset_frame_context = 0;
     cm->refresh_frame_context = 0;
     cm->frame_parallel_decoding_mode = 1;
   }
 
   cm->frame_context_idx = vp9_rb_read_literal(rb, NUM_FRAME_CONTEXTS_LG2);
 
+  if ((cm->frame_type == KEY_FRAME) ||
+      cm->error_resilient_mode || cm->intra_only)
+    vp9_setup_past_independence(cm, xd);
+
   setup_loopfilter(pbi, rb);
   setup_quantization(pbi, rb);
   setup_segmentation(pbi, rb);
@@ -1215,7 +1216,7 @@ int vp9_decode_frame(VP9D_COMP *pbi, const uint8_t **p_data_end) {
   if (!pc->error_resilient_mode && !pc->frame_parallel_decoding_mode) {
     vp9_adapt_coef_probs(pc);
 
-    if (!keyframe) {
+    if ((!keyframe) && (!pc->intra_only)) {
       vp9_adapt_mode_probs(pc);
       vp9_adapt_mode_context(pc);
       vp9_adapt_nmv_probs(pc, xd->allow_high_precision_mv);