vpx/vp8/decoder/decodemv.c
John Koleszar 3085025fa1 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
2010-06-09 11:47:24 -04:00

422 lines
14 KiB
C

/*
* Copyright (c) 2010 The VP8 project authors. All Rights Reserved.
*
* 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
* be found in the AUTHORS file in the root of the source tree.
*/
#include "treereader.h"
#include "entropymv.h"
#include "entropymode.h"
#include "onyxd_int.h"
#include "findnearmv.h"
#include "demode.h"
#if CONFIG_DEBUG
#include <assert.h>
#endif
static int read_mvcomponent(vp8_reader *r, const MV_CONTEXT *mvc)
{
const vp8_prob *const p = (const vp8_prob *) mvc;
int x = 0;
if (vp8_read(r, p [mvpis_short])) /* Large */
{
int i = 0;
do
{
x += vp8_read(r, p [MVPbits + i]) << i;
}
while (++i < 3);
i = mvlong_width - 1; /* Skip bit 3, which is sometimes implicit */
do
{
x += vp8_read(r, p [MVPbits + i]) << i;
}
while (--i > 3);
if (!(x & 0xFFF0) || vp8_read(r, p [MVPbits + 3]))
x += 8;
}
else /* small */
x = vp8_treed_read(r, vp8_small_mvtree, p + MVPshort);
if (x && vp8_read(r, p [MVPsign]))
x = -x;
return x;
}
static void read_mv(vp8_reader *r, MV *mv, const MV_CONTEXT *mvc)
{
mv->row = (short)(read_mvcomponent(r, mvc) << 1);
mv->col = (short)(read_mvcomponent(r, ++mvc) << 1);
}
static void read_mvcontexts(vp8_reader *bc, MV_CONTEXT *mvc)
{
int i = 0;
do
{
const vp8_prob *up = vp8_mv_update_probs[i].prob;
vp8_prob *p = (vp8_prob *)(mvc + i);
vp8_prob *const pstop = p + MVPcount;
do
{
if (vp8_read(bc, *up++))
{
const vp8_prob x = (vp8_prob)vp8_read_literal(bc, 7);
*p = x ? x << 1 : 1;
}
}
while (++p < pstop);
}
while (++i < 2);
}
static MB_PREDICTION_MODE read_mv_ref(vp8_reader *bc, const vp8_prob *p)
{
const int i = vp8_treed_read(bc, vp8_mv_ref_tree, p);
return (MB_PREDICTION_MODE)i;
}
static MB_PREDICTION_MODE sub_mv_ref(vp8_reader *bc, const vp8_prob *p)
{
const int i = vp8_treed_read(bc, vp8_sub_mv_ref_tree, p);
return (MB_PREDICTION_MODE)i;
}
unsigned int vp8_mv_cont_count[5][4] =
{
{ 0, 0, 0, 0 },
{ 0, 0, 0, 0 },
{ 0, 0, 0, 0 },
{ 0, 0, 0, 0 },
{ 0, 0, 0, 0 }
};
void vp8_decode_mode_mvs(VP8D_COMP *pbi)
{
const MV Zero = { 0, 0};
VP8_COMMON *const pc = & pbi->common;
vp8_reader *const bc = & pbi->bc;
MODE_INFO *mi = pc->mi, *ms;
const int mis = pc->mode_info_stride;
MV_CONTEXT *const mvc = pc->fc.mvc;
int mb_row = -1;
vp8_prob prob_intra;
vp8_prob prob_last;
vp8_prob prob_gf;
vp8_prob prob_skip_false = 0;
if (pc->mb_no_coeff_skip)
prob_skip_false = (vp8_prob)vp8_read_literal(bc, 8);
prob_intra = (vp8_prob)vp8_read_literal(bc, 8);
prob_last = (vp8_prob)vp8_read_literal(bc, 8);
prob_gf = (vp8_prob)vp8_read_literal(bc, 8);
ms = pc->mi - 1;
if (vp8_read_bit(bc))
{
int i = 0;
do
{
pc->fc.ymode_prob[i] = (vp8_prob) vp8_read_literal(bc, 8);
}
while (++i < 4);
}
if (vp8_read_bit(bc))
{
int i = 0;
do
{
pc->fc.uv_mode_prob[i] = (vp8_prob) vp8_read_literal(bc, 8);
}
while (++i < 3);
}
read_mvcontexts(bc, mvc);
while (++mb_row < pc->mb_rows)
{
int mb_col = -1;
while (++mb_col < pc->mb_cols)
{
MB_MODE_INFO *const mbmi = & mi->mbmi;
MV *const mv = & mbmi->mv.as_mv;
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.
// These specified to 8th pel as they are always compared to MV values that are in 1/8th pel units
xd->mb_to_left_edge = -((mb_col * 16) << 3);
xd->mb_to_right_edge = ((pc->mb_cols - 1 - mb_col) * 16) << 3;
xd->mb_to_top_edge = -((mb_row * 16)) << 3;
xd->mb_to_bottom_edge = ((pc->mb_rows - 1 - mb_row) * 16) << 3;
// If required read in new segmentation data for this MB
if (pbi->mb.update_mb_segmentation_map)
vp8_read_mb_features(bc, mbmi, &pbi->mb);
// Read the macroblock coeff skip flag if this feature is in use, else default to 0
if (pc->mb_no_coeff_skip)
mbmi->mb_skip_coeff = vp8_read(bc, prob_skip_false);
else
mbmi->mb_skip_coeff = 0;
mbmi->uv_mode = DC_PRED;
if ((mbmi->ref_frame = (MV_REFERENCE_FRAME) vp8_read(bc, prob_intra))) /* inter MB */
{
int rct[4];
vp8_prob mv_ref_p [VP8_MVREFS-1];
MV nearest, nearby, best_mv;
if (vp8_read(bc, prob_last))
{
mbmi->ref_frame = (MV_REFERENCE_FRAME)((int)mbmi->ref_frame + (int)(1 + vp8_read(bc, prob_gf)));
}
vp8_find_near_mvs(xd, mi, &nearest, &nearby, &best_mv, rct, mbmi->ref_frame, pbi->common.ref_frame_sign_bias);
vp8_mv_ref_probs(mv_ref_p, rct);
switch (mbmi->mode = read_mv_ref(bc, mv_ref_p))
{
case SPLITMV:
{
const int s = mbmi->partitioning = vp8_treed_read(
bc, vp8_mbsplit_tree, vp8_mbsplit_probs
);
const int num_p = vp8_mbsplit_count [s];
const int *const L = vp8_mbsplits [s];
int j = 0;
do /* for each subset j */
{
B_MODE_INFO *const bmi = mbmi->partition_bmi + j;
MV *const mv = & bmi->mv.as_mv;
int k = -1; /* first block in subset j */
int mv_contz;
while (j != L[++k])
if (k >= 16)
#if CONFIG_DEBUG
assert(0);
#else
;
#endif
mv_contz = vp8_mv_cont(&(vp8_left_bmi(mi, k)->mv.as_mv), &(vp8_above_bmi(mi, k, mis)->mv.as_mv));
switch (bmi->mode = (B_PREDICTION_MODE) sub_mv_ref(bc, vp8_sub_mv_ref_prob2 [mv_contz])) //pc->fc.sub_mv_ref_prob))
{
case NEW4X4:
read_mv(bc, mv, (const MV_CONTEXT *) mvc);
mv->row += best_mv.row;
mv->col += best_mv.col;
#ifdef VPX_MODE_COUNT
vp8_mv_cont_count[mv_contz][3]++;
#endif
break;
case LEFT4X4:
*mv = vp8_left_bmi(mi, k)->mv.as_mv;
#ifdef VPX_MODE_COUNT
vp8_mv_cont_count[mv_contz][0]++;
#endif
break;
case ABOVE4X4:
*mv = vp8_above_bmi(mi, k, mis)->mv.as_mv;
#ifdef VPX_MODE_COUNT
vp8_mv_cont_count[mv_contz][1]++;
#endif
break;
case ZERO4X4:
*mv = Zero;
#ifdef VPX_MODE_COUNT
vp8_mv_cont_count[mv_contz][2]++;
#endif
break;
default:
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". */
do
if (j == L[k])
mi->bmi[k] = *bmi;
while (++k < 16);
}
while (++j < num_p);
}
*mv = mi->bmi[15].mv.as_mv;
break; /* done with SPLITMV */
case NEARMV:
*mv = nearby;
// Clip "next_nearest" so that it does not extend to far out of image
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;
goto propagate_mv;
case NEARESTMV:
*mv = nearest;
// Clip "next_nearest" so that it does not extend to far out of image
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;
goto propagate_mv;
case ZEROMV:
*mv = Zero;
goto propagate_mv;
case NEWMV:
read_mv(bc, mv, (const MV_CONTEXT *) mvc);
mv->row += best_mv.row;
mv->col += best_mv.col;
/* 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 (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;
propagate_mv: /* same MV throughout */
{
//int i=0;
//do
//{
// mi->bmi[i].mv.as_mv = *mv;
//}
//while( ++i < 16);
mi->bmi[0].mv.as_mv = *mv;
mi->bmi[1].mv.as_mv = *mv;
mi->bmi[2].mv.as_mv = *mv;
mi->bmi[3].mv.as_mv = *mv;
mi->bmi[4].mv.as_mv = *mv;
mi->bmi[5].mv.as_mv = *mv;
mi->bmi[6].mv.as_mv = *mv;
mi->bmi[7].mv.as_mv = *mv;
mi->bmi[8].mv.as_mv = *mv;
mi->bmi[9].mv.as_mv = *mv;
mi->bmi[10].mv.as_mv = *mv;
mi->bmi[11].mv.as_mv = *mv;
mi->bmi[12].mv.as_mv = *mv;
mi->bmi[13].mv.as_mv = *mv;
mi->bmi[14].mv.as_mv = *mv;
mi->bmi[15].mv.as_mv = *mv;
}
break;
default:;
#if CONFIG_DEBUG
assert(0);
#endif
}
}
else
{
/* MB is intra coded */
int j = 0;
do
{
mi->bmi[j].mv.as_mv = Zero;
}
while (++j < 16);
*mv = Zero;
if ((mbmi->mode = (MB_PREDICTION_MODE) vp8_read_ymode(bc, pc->fc.ymode_prob)) == B_PRED)
{
int j = 0;
do
{
mi->bmi[j].mode = (B_PREDICTION_MODE)vp8_read_bmode(bc, pc->fc.bmode_prob);
}
while (++j < 16);
}
mbmi->uv_mode = (MB_PREDICTION_MODE)vp8_read_uv_mode(bc, pc->fc.uv_mode_prob);
}
mi++; // next macroblock
}
mi++; // skip left predictor each row
}
}