Removed the reset of mode_info from previous frame

Prior to this commit, both encoder and decoder reset mode/mv info from
previous frame in error resilient mode to ensure bitstreams are able to
decode when there is loss of frame in decoder side. However, this is
not necessary. This commit changed to remove the reset, so encoder can
continue to use mode/mv/partition information from previously encoded
frame without affecting decodeablilty under loss of frame.

Change-Id: I0279f862900dc647fb471ae3389770bb1b9f454f

diff --git a/vp9/common/vp9_entropymode.c b/vp9/common/vp9_entropymode.c
index 25cba7fbe7e9fbc4015dd2a5acc637ab58d2823a..8921539367aa009afa719af83118eb0c5e3edea2 100644 (file)
--- a/vp9/common/vp9_entropymode.c
+++ b/vp9/common/vp9_entropymode.c
@@ -465,8 +465,10 @@ void vp9_setup_past_independence(VP9_COMMON *cm) {
     cm->frame_contexts[cm->frame_context_idx] = cm->fc;
   }
 
-  vpx_memset(cm->prev_mip, 0,
-             cm->mode_info_stride * (cm->mi_rows + 1) * sizeof(MODE_INFO));
+  if (frame_is_intra_only(cm))
+    vpx_memset(cm->prev_mip, 0,
+               cm->mode_info_stride * (cm->mi_rows + 1) * sizeof(MODE_INFO));
+
   vpx_memset(cm->mip, 0,
              cm->mode_info_stride * (cm->mi_rows + 1) * sizeof(MODE_INFO));
 

diff --git a/vp9/common/vp9_mvref_common.c b/vp9/common/vp9_mvref_common.c
index ff02622102e760be94365018f8eaeb5fc9829751..3b0d1e9829bbc6062dec805f5955fb193f2cf657 100644 (file)
--- a/vp9/common/vp9_mvref_common.c
+++ b/vp9/common/vp9_mvref_common.c
@@ -196,7 +196,8 @@ void vp9_find_mv_refs_idx(const VP9_COMMON *cm, const MACROBLOCKD *xd,
   const int *ref_sign_bias = cm->ref_frame_sign_bias;
   int i, refmv_count = 0;
   const POSITION *const mv_ref_search = mv_ref_blocks[mi->mbmi.sb_type];
-  const MB_MODE_INFO *const prev_mbmi = prev_mi ? &prev_mi->mbmi : NULL;
+  const MB_MODE_INFO *const prev_mbmi = cm->coding_use_prev_mi && prev_mi ?
+      &prev_mi->mbmi : NULL;
   int different_ref_found = 0;
   int context_counter = 0;
 

diff --git a/vp9/common/vp9_onyxc_int.h b/vp9/common/vp9_onyxc_int.h
index 97983c596ccec0627ea1f26de31f7b3c3a6d2b06..e6d6ea7f0ecd71d429ed8a76f09ab5fc52af7908 100644 (file)
--- a/vp9/common/vp9_onyxc_int.h
+++ b/vp9/common/vp9_onyxc_int.h
@@ -224,6 +224,11 @@ typedef struct VP9Common {
   int error_resilient_mode;
   int frame_parallel_decoding_mode;
 
+  // Flag indicates if prev_mi can be used in coding:
+  //   0: encoder assumes decoder does not have prev_mi
+  //   1: encoder assumes decoder has and uses prev_mi
+  unsigned int coding_use_prev_mi;
+
   int log2_tile_cols, log2_tile_rows;
 
   // Private data associated with the frame buffer callbacks.
@@ -302,7 +307,6 @@ static INLINE void set_mi_row_col(MACROBLOCKD *xd, const TileInfo *const tile,
 static void set_prev_mi(VP9_COMMON *cm) {
   const int use_prev_in_find_mv_refs = cm->width == cm->last_width &&
                                        cm->height == cm->last_height &&
-                                       !cm->error_resilient_mode &&
                                        !cm->intra_only &&
                                        cm->last_show_frame;
   // Special case: set prev_mi to NULL when the previous mode info

diff --git a/vp9/decoder/vp9_decodeframe.c b/vp9/decoder/vp9_decodeframe.c
index d37afa5bc2aada603eb5d2cc38f8e6ecef0abcb9..2d07dd60912fcf2af4001dd14afe988969b1083e 100644 (file)
--- a/vp9/decoder/vp9_decodeframe.c
+++ b/vp9/decoder/vp9_decodeframe.c
@@ -350,9 +350,9 @@ static void set_offsets(VP9_COMMON *const cm, MACROBLOCKD *const xd,
 
   xd->mi_8x8 = cm->mi_grid_visible + offset;
   xd->prev_mi_8x8 = cm->prev_mi_grid_visible + offset;
-  // Special case: if prev_mi is NULL, the previous mode info context
-  // cannot be used.
-  xd->last_mi = cm->prev_mi ? xd->prev_mi_8x8[0] : NULL;
+
+  xd->last_mi = cm->coding_use_prev_mi && cm->prev_mi ?
+      xd->prev_mi_8x8[0] : NULL;
 
   xd->mi_8x8[0] = xd->mi_stream + offset - tile_offset;
   xd->mi_8x8[0]->mbmi.sb_type = bsize;
@@ -1203,9 +1203,11 @@ static size_t read_uncompressed_header(VP9D_COMP *pbi,
   }
 
   if (!cm->error_resilient_mode) {
+    cm->coding_use_prev_mi = 1;
     cm->refresh_frame_context = vp9_rb_read_bit(rb);
     cm->frame_parallel_decoding_mode = vp9_rb_read_bit(rb);
   } else {
+    cm->coding_use_prev_mi = 0;
     cm->refresh_frame_context = 0;
     cm->frame_parallel_decoding_mode = 1;
   }
@@ -1373,7 +1375,10 @@ int vp9_decode_frame(VP9D_COMP *pbi, const uint8_t **p_data_end) {
   alloc_tile_storage(pbi, tile_rows, tile_cols);
 
   xd->mode_info_stride = cm->mode_info_stride;
-  set_prev_mi(cm);
+  if (cm->coding_use_prev_mi)
+    set_prev_mi(cm);
+  else
+    cm->prev_mi = NULL;
 
   setup_plane_dequants(cm, xd, cm->base_qindex);
   vp9_setup_block_planes(xd, cm->subsampling_x, cm->subsampling_y);

diff --git a/vp9/encoder/vp9_encodeframe.c b/vp9/encoder/vp9_encodeframe.c
index 0022ef3b42386ec2baf7254cb6c4d0f4c77f8438..15ad3bc871622c4d1ba2adc54bfe1184879e5413 100644 (file)
--- a/vp9/encoder/vp9_encodeframe.c
+++ b/vp9/encoder/vp9_encodeframe.c
@@ -555,8 +555,6 @@ static void set_offsets(VP9_COMP *cpi, const TileInfo *const tile,
   xd->mi_8x8 = cm->mi_grid_visible + idx_str;
   xd->prev_mi_8x8 = cm->prev_mi_grid_visible + idx_str;
 
-  // Special case: if prev_mi is NULL, the previous mode info context
-  // cannot be used.
   xd->last_mi = cm->prev_mi ? xd->prev_mi_8x8[0] : NULL;
 
   xd->mi_8x8[0] = cm->mi + idx_str;

diff --git a/vp9/encoder/vp9_onyx_if.c b/vp9/encoder/vp9_onyx_if.c
index 88cf73c57fa9fb87e9e64b6d26f3f1f311e1780d..db6349c76ff31b8e766670313943f81de370d13b 100644 (file)
--- a/vp9/encoder/vp9_onyx_if.c
+++ b/vp9/encoder/vp9_onyx_if.c
@@ -3153,7 +3153,11 @@ static void encode_frame_to_data_rate(VP9_COMP *cpi,
     cm->error_resilient_mode = (cpi->oxcf.error_resilient_mode != 0);
     cm->frame_parallel_decoding_mode =
       (cpi->oxcf.frame_parallel_decoding_mode != 0);
+
+    // By default, encoder assumes decoder can use prev_mi.
+    cm->coding_use_prev_mi = 1;
     if (cm->error_resilient_mode) {
+      cm->coding_use_prev_mi = 0;
       cm->frame_parallel_decoding_mode = 1;
       cm->reset_frame_context = 0;
       cm->refresh_frame_context = 0;