ref: 3085025fa1392e99bc95a519657374f2e9a4249b
parent: 4bb895e85401d81d7dd2615380309812edfefc5e
author: John Koleszar <jkoleszar@google.com>
date: Wed Jun 9 07:29:20 EDT 2010
Remove secondary mv clamping from decode stage This patch removes the secondary MV clamping from the MV decoder. This behavior was consistent with limits placed on non-split MVs by the reference encoder, but was inconsistent with the MVs generated in the split case. The purpose of this secondary clamping was only to prevent crashes on invalid data. It was not intended to be a behaviour an encoder could or should rely on. Instead of doing additional clamping in a way that changes the entropy context, the secondary clamp is removed and the border handling is made implmentation specific. With respect to the spec, the border is treated as essentially infinite, limited only by the clamping performed on the near/nearest reference and the maximum encodable magnitude of the residual MV. This does not affect any currently produced streams. Change-Id: I68d35a2fbb51570d6569eab4ad233961405230a3
--- a/vp8/common/blockd.h
+++ b/vp8/common/blockd.h
@@ -174,9 +174,8 @@
int dc_diff;
unsigned char segment_id; // Which set of segmentation parameters should be used for this MB
int force_no_skip;
-
+ int need_to_clamp_mvs;
B_MODE_INFO partition_bmi[16];
-
} MB_MODE_INFO;
--- a/vp8/decoder/decodemv.c
+++ b/vp8/decoder/decodemv.c
@@ -171,6 +171,7 @@
VP8_COMMON *const pc = &pbi->common;
MACROBLOCKD *xd = &pbi->mb;
+ mbmi->need_to_clamp_mvs = 0;
vp8dx_bool_decoder_fill(bc);
// Distance of Mb to the various image edges.
@@ -269,6 +270,17 @@
break;
}
+ if (mv->col < xd->mb_to_left_edge
+ - LEFT_TOP_MARGIN
+ || mv->col > xd->mb_to_right_edge
+ + RIGHT_BOTTOM_MARGIN
+ || mv->row < xd->mb_to_top_edge
+ - LEFT_TOP_MARGIN
+ || mv->row > xd->mb_to_bottom_edge
+ + RIGHT_BOTTOM_MARGIN
+ )
+ mbmi->need_to_clamp_mvs = 1;
+
/* Fill (uniform) modes, mvs of jth subset.
Must do it here because ensuing subsets can
refer back to us via "left" or "above". */
@@ -325,28 +337,19 @@
read_mv(bc, mv, (const MV_CONTEXT *) mvc);
mv->row += best_mv.row;
mv->col += best_mv.col;
- /* Encoder should not produce invalid motion vectors, but since
- * arbitrary length MVs can be parsed from the bitstream, we
- * need to clamp them here in case we're reading bad data to
- * avoid a crash.
+
+ /* Don't need to check this on NEARMV and NEARESTMV modes
+ * since those modes clamp the MV. The NEWMV mode does not,
+ * so signal to the prediction stage whether special
+ * handling may be required.
*/
-#if CONFIG_DEBUG
- assert(mv->col >= (xd->mb_to_left_edge - LEFT_TOP_MARGIN));
- assert(mv->col <= (xd->mb_to_right_edge + RIGHT_BOTTOM_MARGIN));
- assert(mv->row >= (xd->mb_to_top_edge - LEFT_TOP_MARGIN));
- assert(mv->row <= (xd->mb_to_bottom_edge + RIGHT_BOTTOM_MARGIN));
-#endif
+ if (mv->col < xd->mb_to_left_edge - LEFT_TOP_MARGIN
+ || mv->col > xd->mb_to_right_edge + RIGHT_BOTTOM_MARGIN
+ || mv->row < xd->mb_to_top_edge - LEFT_TOP_MARGIN
+ || mv->row > xd->mb_to_bottom_edge + RIGHT_BOTTOM_MARGIN
+ )
+ mbmi->need_to_clamp_mvs = 1;
- if (mv->col < (xd->mb_to_left_edge - LEFT_TOP_MARGIN))
- mv->col = xd->mb_to_left_edge - LEFT_TOP_MARGIN;
- else if (mv->col > xd->mb_to_right_edge + RIGHT_BOTTOM_MARGIN)
- mv->col = xd->mb_to_right_edge + RIGHT_BOTTOM_MARGIN;
-
- if (mv->row < (xd->mb_to_top_edge - LEFT_TOP_MARGIN))
- mv->row = xd->mb_to_top_edge - LEFT_TOP_MARGIN;
- else if (mv->row > xd->mb_to_bottom_edge + RIGHT_BOTTOM_MARGIN)
- mv->row = xd->mb_to_bottom_edge + RIGHT_BOTTOM_MARGIN;
-
propagate_mv: /* same MV throughout */
{//int i=0;
@@ -381,7 +384,6 @@
assert(0);
#endif
}
-
}
else
{--- a/vp8/decoder/decodframe.c
+++ b/vp8/decoder/decodframe.c
@@ -1,10 +1,10 @@
/*
* Copyright (c) 2010 The VP8 project authors. All Rights Reserved.
*
- * Use of this source code is governed by a BSD-style license
+ * Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
- * in the file PATENTS. All contributing project authors may
+ * in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
@@ -126,6 +126,47 @@
}
}
+
+static void clamp_mv_to_umv_border(MV *mv, const MACROBLOCKD *xd)
+{+ /* If the MV points so far into the UMV border that no visible pixels
+ * are used for reconstruction, the subpel part of the MV can be
+ * discarded and the MV limited to 16 pixels with equivalent results.
+ *
+ * This limit kicks in at 19 pixels for the top and left edges, for
+ * the 16 pixels plus 3 taps right of the central pixel when subpel
+ * filtering. The bottom and right edges use 16 pixels plus 2 pixels
+ * left of the central pixel when filtering.
+ */
+ if (mv->col < (xd->mb_to_left_edge - (19 << 3)))
+ mv->col = xd->mb_to_left_edge - (16 << 3);
+ else if (mv->col > xd->mb_to_right_edge + (18 << 3))
+ mv->col = xd->mb_to_right_edge + (16 << 3);
+
+ if (mv->row < (xd->mb_to_top_edge - (19 << 3)))
+ mv->row = xd->mb_to_top_edge - (16 << 3);
+ else if (mv->row > xd->mb_to_bottom_edge + (18 << 3))
+ mv->row = xd->mb_to_bottom_edge + (16 << 3);
+}
+
+
+static void clamp_mvs(MACROBLOCKD *xd)
+{+ if (xd->mbmi.mode == SPLITMV)
+ {+ int i;
+
+ for (i=0; i<16; i++)
+ clamp_mv_to_umv_border(&xd->block[i].bmi.mv.as_mv, xd);
+ }
+ else
+ {+ clamp_mv_to_umv_border(&xd->mbmi.mv.as_mv, xd);
+ clamp_mv_to_umv_border(&xd->block[16].bmi.mv.as_mv, xd);
+ }
+
+}
+
static void reconstruct_mb(VP8D_COMP *pbi, MACROBLOCKD *xd)
{if (xd->frame_type == KEY_FRAME || xd->mbmi.ref_frame == INTRA_FRAME)
@@ -233,6 +274,8 @@
void vp8_decode_macroblock(VP8D_COMP *pbi, MACROBLOCKD *xd)
{int eobtotal = 0;
+ MV orig_mvs[24];
+ int i, do_clamp = xd->mbmi.need_to_clamp_mvs;
if (xd->mbmi.mb_skip_coeff)
{@@ -243,20 +286,50 @@
eobtotal = vp8_decode_mb_tokens(pbi, xd);
}
- xd->mode_info_context->mbmi.dc_diff = 1;
-
- if (xd->mbmi.mode != B_PRED && xd->mbmi.mode != SPLITMV && eobtotal == 0)
+ /* Perform temporary clamping of the MV to be used for prediction */
+ if (do_clamp)
{- xd->mode_info_context->mbmi.dc_diff = 0;
- skip_recon_mb(pbi, xd);
- return;
+ if (xd->mbmi.mode == SPLITMV)
+ for (i=0; i<24; i++)
+ orig_mvs[i] = xd->block[i].bmi.mv.as_mv;
+ else
+ {+ orig_mvs[0] = xd->mbmi.mv.as_mv;
+ orig_mvs[1] = xd->block[16].bmi.mv.as_mv;
+ }
+ clamp_mvs(xd);
}
- if (xd->segmentation_enabled)
- mb_init_dequantizer(pbi, xd);
+ xd->mode_info_context->mbmi.dc_diff = 1;
- de_quantand_idct(pbi, xd);
- reconstruct_mb(pbi, xd);
+ do {+ if (xd->mbmi.mode != B_PRED && xd->mbmi.mode != SPLITMV && eobtotal == 0)
+ {+ xd->mode_info_context->mbmi.dc_diff = 0;
+ skip_recon_mb(pbi, xd);
+ break;
+ }
+
+ if (xd->segmentation_enabled)
+ mb_init_dequantizer(pbi, xd);
+
+ de_quantand_idct(pbi, xd);
+ reconstruct_mb(pbi, xd);
+ } while(0);
+
+
+ /* Restore the original MV so as not to affect the entropy context. */
+ if (do_clamp)
+ {+ if (xd->mbmi.mode == SPLITMV)
+ for (i=0; i<24; i++)
+ xd->block[i].bmi.mv.as_mv = orig_mvs[i];
+ else
+ {+ xd->mbmi.mv.as_mv = orig_mvs[0];
+ xd->block[16].bmi.mv.as_mv = orig_mvs[1];
+ }
+ }
}
static int get_delta_q(vp8_reader *bc, int prev, int *q_update)
@@ -314,7 +387,9 @@
for (mb_col = 0; mb_col < pc->mb_cols; mb_col++)
{// Take a copy of the mode and Mv information for this macroblock into the xd->mbmi
- vpx_memcpy(&xd->mbmi, &xd->mode_info_context->mbmi, 32); //sizeof(MB_MODE_INFO) );
+ // the partition_bmi array is unused in the decoder, so don't copy it.
+ vpx_memcpy(&xd->mbmi, &xd->mode_info_context->mbmi,
+ sizeof(MB_MODE_INFO) - sizeof(xd->mbmi.partition_bmi));
if (xd->mbmi.mode == SPLITMV || xd->mbmi.mode == B_PRED)
{--- a/vp8/decoder/threading.c
+++ b/vp8/decoder/threading.c
@@ -1,10 +1,10 @@
/*
* Copyright (c) 2010 The VP8 project authors. All Rights Reserved.
*
- * Use of this source code is governed by a BSD-style license
+ * Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
- * in the file PATENTS. All contributing project authors may
+ * in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
@@ -154,7 +154,9 @@
}
// Take a copy of the mode and Mv information for this macroblock into the xd->mbmi
- vpx_memcpy(&xd->mbmi, &xd->mode_info_context->mbmi, 32); //sizeof(MB_MODE_INFO) );
+ // the partition_bmi array is unused in the decoder, so don't copy it.
+ vpx_memcpy(&xd->mbmi, &xd->mode_info_context->mbmi,
+ sizeof(MB_MODE_INFO) - sizeof(xd->mbmi.partition_bmi));
if (xd->mbmi.mode == SPLITMV || xd->mbmi.mode == B_PRED)
{