shithub: libvpx

Download patch

ref: 896d79a57edb2d2dfcdfba3e71d3b94f008a4a69
parent: 279dbb9a309d561f29472a25fd2872523f2a80ce
author: Yaowu Xu <yaowu@google.com>
date: Wed Feb 12 06:04:58 EST 2014 

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


--- a/vp9/common/vp9_entropymode.c
+++ b/vp9/common/vp9_entropymode.c
@@ -465,8 +465,10 @@
     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));
 
--- a/vp9/common/vp9_mvref_common.c
+++ b/vp9/common/vp9_mvref_common.c
@@ -196,7 +196,8 @@
   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;
 
--- a/vp9/common/vp9_onyxc_int.h
+++ b/vp9/common/vp9_onyxc_int.h
@@ -224,6 +224,11 @@
   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 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
--- a/vp9/decoder/vp9_decodeframe.c
+++ b/vp9/decoder/vp9_decodeframe.c
@@ -350,10 +350,10 @@
 
   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;
   for (y = 0; y < y_mis; ++y)
@@ -1203,9 +1203,11 @@
   }
 
   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 @@
   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);
--- a/vp9/encoder/vp9_encodeframe.c
+++ b/vp9/encoder/vp9_encodeframe.c
@@ -555,8 +555,6 @@
   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;
--- a/vp9/encoder/vp9_onyx_if.c
+++ b/vp9/encoder/vp9_onyx_if.c
@@ -3153,7 +3153,11 @@
     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;
-- 
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