RFC 6386
VP8 Data Format and Decoding Guide
20.6. dixie_loopfilter.c
---- Begin code block -------------------------------------- /* * Copyright (c) 2010, 2011, Google Inc. 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 "dixie.h" #include "dixie_loopfilter.h" #define ABS(x) ((x) >= 0 ? (x) : -(x)) #define p3 pixels[-4*stride] #define p2 pixels[-3*stride] #define p1 pixels[-2*stride] #define p0 pixels[-1*stride] #define q0 pixels[ 0*stride] #define q1 pixels[ 1*stride] #define q2 pixels[ 2*stride] #define q3 pixels[ 3*stride] #define static static int saturate_int8(int x) { if (x < -128) return -128; if (x > 127) return 127; return x; }
static int
saturate_uint8(int x)
{
if (x < 0)
return 0;
if (x > 255)
return 255;
return x;
}
static int
high_edge_variance(unsigned char *pixels,
int stride,
int hev_threshold)
{
return ABS(p1 - p0) > hev_threshold ||
ABS(q1 - q0) > hev_threshold;
}
static int
simple_threshold(unsigned char *pixels,
int stride,
int filter_limit)
{
return (ABS(p0 - q0) * 2 + (ABS(p1 - q1) >> 1)) <= filter_limit;
}
static int
normal_threshold(unsigned char *pixels,
int stride,
int edge_limit,
int interior_limit)
{
int E = edge_limit;
int I = interior_limit;
return simple_threshold(pixels, stride, 2 * E + I)
&& ABS(p3 - p2) <= I && ABS(p2 - p1) <= I
&& ABS(p1 - p0) <= I && ABS(q3 - q2) <= I
&& ABS(q2 - q1) <= I && ABS(q1 - q0) <= I;
}
static void
filter_common(unsigned char *pixels,
int stride,
int use_outer_taps)
{
int a, f1, f2;
a = 3 * (q0 - p0);
if (use_outer_taps)
a += saturate_int8(p1 - q1);
a = saturate_int8(a);
f1 = ((a + 4 > 127) ? 127 : a + 4) >> 3;
f2 = ((a + 3 > 127) ? 127 : a + 3) >> 3;
p0 = saturate_uint8(p0 + f2);
q0 = saturate_uint8(q0 - f1);
if (!use_outer_taps)
{
/* This handles the case of subblock_filter()
* (from the bitstream guide.
*/
a = (f1 + 1) >> 1;
p1 = saturate_uint8(p1 + a);
q1 = saturate_uint8(q1 - a);
}
}
static void
filter_mb_edge(unsigned char *pixels,
int stride)
{
int w, a;
w = saturate_int8(saturate_int8(p1 - q1) + 3 * (q0 - p0));
a = (27 * w + 63) >> 7;
p0 = saturate_uint8(p0 + a);
q0 = saturate_uint8(q0 - a);
a = (18 * w + 63) >> 7;
p1 = saturate_uint8(p1 + a);
q1 = saturate_uint8(q1 - a);
a = (9 * w + 63) >> 7;
p2 = saturate_uint8(p2 + a);
q2 = saturate_uint8(q2 - a);
}
static void
filter_mb_v_edge(unsigned char *src,
int stride,
int edge_limit,
int interior_limit,
int hev_threshold,
int size)
{
int i;
for (i = 0; i < 8 * size; i++)
{
if (normal_threshold(src, 1, edge_limit, interior_limit))
{
if (high_edge_variance(src, 1, hev_threshold))
filter_common(src, 1, 1);
else
filter_mb_edge(src, 1);
}
src += stride;
}
}
static void
filter_subblock_v_edge(unsigned char *src,
int stride,
int edge_limit,
int interior_limit,
int hev_threshold,
int size)
{
int i;
for (i = 0; i < 8 * size; i++)
{
if (normal_threshold(src, 1, edge_limit, interior_limit))
filter_common(src, 1,
high_edge_variance(src, 1, hev_threshold));
src += stride;
}
}
static void
filter_mb_h_edge(unsigned char *src,
int stride,
int edge_limit,
int interior_limit,
int hev_threshold,
int size)
{
int i;
for (i = 0; i < 8 * size; i++)
{
if (normal_threshold(src, stride, edge_limit,
interior_limit))
{
if (high_edge_variance(src, stride, hev_threshold))
filter_common(src, stride, 1);
else
filter_mb_edge(src, stride);
}
src += 1;
}
}
static void
filter_subblock_h_edge(unsigned char *src,
int stride,
int edge_limit,
int interior_limit,
int hev_threshold,
int size)
{
int i;
for (i = 0; i < 8 * size; i++)
{
if (normal_threshold(src, stride, edge_limit,
interior_limit))
filter_common(src, stride,
high_edge_variance(src, stride,
hev_threshold));
src += 1;
}
}
static void
filter_v_edge_simple(unsigned char *src,
int stride,
int filter_limit)
{
int i;
for (i = 0; i < 16; i++)
{
if (simple_threshold(src, 1, filter_limit))
filter_common(src, 1, 1);
src += stride;
}
}
static void
filter_h_edge_simple(unsigned char *src,
int stride,
int filter_limit)
{
int i;
for (i = 0; i < 16; i++)
{
if (simple_threshold(src, stride, filter_limit))
filter_common(src, stride, 1);
src += 1;
}
}
static void
calculate_filter_parameters(struct vp8_decoder_ctx *ctx,
struct mb_info *mbi,
int *edge_limit_,
int *interior_limit_,
int *hev_threshold_)
{
int filter_level, interior_limit, hev_threshold;
/* Reference code/spec seems to conflate filter_level and
* edge_limit
*/
filter_level = ctx->loopfilter_hdr.level;
if (ctx->segment_hdr.enabled)
{
if (!ctx->segment_hdr.abs)
filter_level +=
ctx->segment_hdr.lf_level[mbi->base.segment_id];
else
filter_level =
ctx->segment_hdr.lf_level[mbi->base.segment_id];
}
if (filter_level > 63)
filter_level = 63;
else if (filter_level < 0)
filter_level = 0;
if (ctx->loopfilter_hdr.delta_enabled)
{
filter_level +=
ctx->loopfilter_hdr.ref_delta[mbi->base.ref_frame];
if (mbi->base.ref_frame == CURRENT_FRAME)
{
if (mbi->base.y_mode == B_PRED)
filter_level += ctx->loopfilter_hdr.mode_delta[0];
}
else if (mbi->base.y_mode == ZEROMV)
filter_level += ctx->loopfilter_hdr.mode_delta[1];
else if (mbi->base.y_mode == SPLITMV)
filter_level += ctx->loopfilter_hdr.mode_delta[3];
else
filter_level += ctx->loopfilter_hdr.mode_delta[2];
}
if (filter_level > 63)
filter_level = 63;
else if (filter_level < 0)
filter_level = 0;
interior_limit = filter_level;
if (ctx->loopfilter_hdr.sharpness)
{
interior_limit >>= ctx->loopfilter_hdr.sharpness > 4 ? 2 : 1;
if (interior_limit > 9 - ctx->loopfilter_hdr.sharpness)
interior_limit = 9 - ctx->loopfilter_hdr.sharpness;
}
if (interior_limit < 1)
interior_limit = 1;
hev_threshold = (filter_level >= 15);
if (filter_level >= 40)
hev_threshold++;
if (filter_level >= 20 && !ctx->frame_hdr.is_keyframe)
hev_threshold++;
*edge_limit_ = filter_level;
*interior_limit_ = interior_limit;
*hev_threshold_ = hev_threshold;
}
static void
filter_row_normal(struct vp8_decoder_ctx *ctx,
unsigned int row,
unsigned int start_col,
unsigned int num_cols)
{
unsigned char *y, *u, *v;
int stride, uv_stride;
struct mb_info *mbi;
unsigned int col;
/* Adjust pointers based on row, start_col */
stride = ctx->ref_frames[CURRENT_FRAME]->img.stride[PLANE_Y];
uv_stride = ctx->ref_frames[CURRENT_FRAME]->img.stride[PLANE_U];
y = ctx->ref_frames[CURRENT_FRAME]->img.planes[PLANE_Y];
u = ctx->ref_frames[CURRENT_FRAME]->img.planes[PLANE_U];
v = ctx->ref_frames[CURRENT_FRAME]->img.planes[PLANE_V];
y += (stride * row + start_col) * 16;
u += (uv_stride * row + start_col) * 8;
v += (uv_stride * row + start_col) * 8;
mbi = ctx->mb_info_rows[row] + start_col;
for (col = start_col; col < start_col + num_cols; col++)
{
int edge_limit, interior_limit, hev_threshold;
/* TODO: Only need to recalculate every MB if segmentation is
* enabled.
*/
calculate_filter_parameters(ctx, mbi, &edge_limit,
&interior_limit, &hev_threshold);
if (edge_limit)
{
if (col)
{
filter_mb_v_edge(y, stride, edge_limit + 2,
interior_limit, hev_threshold, 2);
filter_mb_v_edge(u, uv_stride, edge_limit + 2,
interior_limit, hev_threshold, 1);
filter_mb_v_edge(v, uv_stride, edge_limit + 2,
interior_limit, hev_threshold, 1);
}
/* NOTE: This conditional is actually dependent on the
* number of coefficients decoded, not the skip flag as
* coded in the bitstream. The tokens task is expected
* to set 31 if there is *any* non-zero data.
*/
if (mbi->base.eob_mask
|| mbi->base.y_mode == SPLITMV
|| mbi->base.y_mode == B_PRED)
{
filter_subblock_v_edge(y + 4, stride, edge_limit,
interior_limit, hev_threshold,
2);
filter_subblock_v_edge(y + 8, stride, edge_limit,
interior_limit, hev_threshold,
2);
filter_subblock_v_edge(y + 12, stride, edge_limit,
interior_limit, hev_threshold,
2);
filter_subblock_v_edge(u + 4, uv_stride, edge_limit,
interior_limit, hev_threshold,
1);
filter_subblock_v_edge(v + 4, uv_stride, edge_limit,
interior_limit, hev_threshold,
1);
}
if (row)
{
filter_mb_h_edge(y, stride, edge_limit + 2,
interior_limit, hev_threshold, 2);
filter_mb_h_edge(u, uv_stride, edge_limit + 2,
interior_limit, hev_threshold, 1);
filter_mb_h_edge(v, uv_stride, edge_limit + 2,
interior_limit, hev_threshold, 1);
}
if (mbi->base.eob_mask
|| mbi->base.y_mode == SPLITMV
|| mbi->base.y_mode == B_PRED)
{
filter_subblock_h_edge(y + 4 * stride, stride,
edge_limit, interior_limit,
hev_threshold, 2);
filter_subblock_h_edge(y + 8 * stride, stride,
edge_limit, interior_limit,
hev_threshold, 2);
filter_subblock_h_edge(y + 12 * stride, stride,
edge_limit, interior_limit,
hev_threshold, 2);
filter_subblock_h_edge(u + 4 * uv_stride, uv_stride,
edge_limit, interior_limit,
hev_threshold, 1);
filter_subblock_h_edge(v + 4 * uv_stride, uv_stride,
edge_limit, interior_limit,
hev_threshold, 1);
}
}
y += 16;
u += 8;
v += 8;
mbi++;
}
}
static void
filter_row_simple(struct vp8_decoder_ctx *ctx,
unsigned int row,
unsigned int start_col,
unsigned int num_cols)
{
unsigned char *y;
int stride;
struct mb_info *mbi;
unsigned int col;
/* Adjust pointers based on row, start_col */
stride = ctx->ref_frames[CURRENT_FRAME]->img.stride[PLANE_Y];
y = ctx->ref_frames[CURRENT_FRAME]->img.planes[PLANE_Y];
y += (stride * row + start_col) * 16;
mbi = ctx->mb_info_rows[row] + start_col;
for (col = start_col; col < start_col + num_cols; col++)
{
int edge_limit, interior_limit, hev_threshold;
/* TODO: Only need to recalculate every MB if segmentation is
* enabled.
*/
calculate_filter_parameters(ctx, mbi, &edge_limit,
&interior_limit, &hev_threshold);
if (edge_limit)
{
/* NOTE: This conditional is actually dependent on the
* number of coefficients decoded, not the skip flag as
* coded in the bitstream. The tokens task is expected
* to set 31 if there is *any* non-zero data.
*/
int filter_subblocks = (mbi->base.eob_mask
|| mbi->base.y_mode == SPLITMV
|| mbi->base.y_mode == B_PRED);
int mb_limit = (edge_limit + 2) * 2 + interior_limit;
int b_limit = edge_limit * 2 + interior_limit;
if (col)
filter_v_edge_simple(y, stride, mb_limit);
if (filter_subblocks)
{
filter_v_edge_simple(y + 4, stride, b_limit);
filter_v_edge_simple(y + 8, stride, b_limit);
filter_v_edge_simple(y + 12, stride, b_limit);
}
if (row)
filter_h_edge_simple(y, stride, mb_limit);
if (filter_subblocks)
{
filter_h_edge_simple(y + 4 * stride, stride,
b_limit);
filter_h_edge_simple(y + 8 * stride, stride,
b_limit);
filter_h_edge_simple(y + 12 * stride, stride,
b_limit);
}
}
y += 16;
mbi++;
}
}
void
vp8_dixie_loopfilter_process_row(struct vp8_decoder_ctx *ctx,
unsigned int row,
unsigned int start_col,
unsigned int num_cols)
{
if (ctx->loopfilter_hdr.use_simple)
filter_row_simple(ctx, row, start_col, num_cols);
else
filter_row_normal(ctx, row, start_col, num_cols);
}
---- End code block ----------------------------------------
20.7. dixie_loopfilter.h
---- Begin code block --------------------------------------
/*
* Copyright (c) 2010, 2011, Google Inc. 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.
*/
#ifndef DIXIE_LOOPFILTER_H
#define DIXIE_LOOPFILTER_H
void
vp8_dixie_loopfilter_process_row(struct vp8_decoder_ctx *ctx,
unsigned int row,
unsigned int start_col,
unsigned int num_cols);
#endif
---- End code block ----------------------------------------
20.8. idct_add.c
---- Begin code block -------------------------------------- /* * Copyright (c) 2010, 2011, Google Inc. 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 "dixie.h" #include "idct_add.h" #include <assert.h> void vp8_dixie_walsh(const short *input, short *output) { int i; int a1, b1, c1, d1; int a2, b2, c2, d2; const short *ip = input; short *op = output; for (i = 0; i < 4; i++) { a1 = ip[0] + ip[12]; b1 = ip[4] + ip[8]; c1 = ip[4] - ip[8]; d1 = ip[0] - ip[12]; op[0] = a1 + b1; op[4] = c1 + d1; op[8] = a1 - b1; op[12] = d1 - c1; ip++; op++; } ip = output; op = output;
for (i = 0; i < 4; i++)
{
a1 = ip[0] + ip[3];
b1 = ip[1] + ip[2];
c1 = ip[1] - ip[2];
d1 = ip[0] - ip[3];
a2 = a1 + b1;
b2 = c1 + d1;
c2 = a1 - b1;
d2 = d1 - c1;
op[0] = (a2 + 3) >> 3;
op[1] = (b2 + 3) >> 3;
op[2] = (c2 + 3) >> 3;
op[3] = (d2 + 3) >> 3;
ip += 4;
op += 4;
}
}
#define cospi8sqrt2minus1 20091
#define sinpi8sqrt2 35468
#define rounding 0
static void
idct_columns(const short *input, short *output)
{
int i;
int a1, b1, c1, d1;
const short *ip = input;
short *op = output;
int temp1, temp2;
int shortpitch = 4;
for (i = 0; i < 4; i++)
{
a1 = ip[0] + ip[8];
b1 = ip[0] - ip[8];
temp1 = (ip[4] * sinpi8sqrt2 + rounding) >> 16;
temp2 = ip[12] +
((ip[12] * cospi8sqrt2minus1 + rounding) >> 16);
c1 = temp1 - temp2;
temp1 = ip[4] +
((ip[4] * cospi8sqrt2minus1 + rounding) >> 16);
temp2 = (ip[12] * sinpi8sqrt2 + rounding) >> 16;
d1 = temp1 + temp2;
op[shortpitch*0] = a1 + d1;
op[shortpitch*3] = a1 - d1;
op[shortpitch*1] = b1 + c1;
op[shortpitch*2] = b1 - c1;
ip++;
op++;
}
}
void
vp8_dixie_idct_add(unsigned char *recon,
const unsigned char *predict,
int stride,
const short *coeffs)
{
int i;
int a1, b1, c1, d1, temp1, temp2;
short tmp[16];
idct_columns(coeffs, tmp);
coeffs = tmp;
for (i = 0; i < 4; i++)
{
a1 = coeffs[0] + coeffs[2];
b1 = coeffs[0] - coeffs[2];
temp1 = (coeffs[1] * sinpi8sqrt2 + rounding) >> 16;
temp2 = coeffs[3] +
((coeffs[3] * cospi8sqrt2minus1 + rounding) >> 16);
c1 = temp1 - temp2;
temp1 = coeffs[1] +
((coeffs[1] * cospi8sqrt2minus1 + rounding) >> 16);
temp2 = (coeffs[3] * sinpi8sqrt2 + rounding) >> 16;
d1 = temp1 + temp2;
recon[0] = CLAMP_255(predict[0] + ((a1 + d1 + 4) >> 3));
recon[3] = CLAMP_255(predict[3] + ((a1 - d1 + 4) >> 3));
recon[1] = CLAMP_255(predict[1] + ((b1 + c1 + 4) >> 3));
recon[2] = CLAMP_255(predict[2] + ((b1 - c1 + 4) >> 3));
coeffs += 4;
recon += stride;
predict += stride;
}
}
---- End code block ----------------------------------------
20.9. idct_add.h
---- Begin code block --------------------------------------
/*
* Copyright (c) 2010, 2011, Google Inc. 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.
*/
#ifndef IDCT_ADD_H
#define IDCT_ADD_H
void
vp8_dixie_idct_add_init(struct vp8_decoder_ctx *ctx);
void
vp8_dixie_idct_add(unsigned char *recon,
const unsigned char *predict,
int stride,
const short *coeffs);
void
vp8_dixie_walsh(const short *in, short *out);
void
vp8_dixie_idct_add_process_row(struct vp8_decoder_ctx *ctx,
short *coeffs,
unsigned int row,
unsigned int start_col,
unsigned int num_cols);
#endif
---- End code block ----------------------------------------
20.10. mem.h
---- Begin code block -------------------------------------- /* * Copyright (c) 2010, 2011, Google Inc. 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. */ #ifndef VPX_PORTS_MEM_H #define VPX_PORTS_MEM_H #include "vpx_config.h" #include "vpx_integer.h" #if defined(__GNUC__) && __GNUC__ #define DECLARE_ALIGNED(n,typ,val) typ val __attribute__ \ ((aligned (n))) #elif defined(_MSC_VER) #define DECLARE_ALIGNED(n,typ,val) __declspec(align(n)) typ val #else #warning No alignment directives known for this compiler. #define DECLARE_ALIGNED(n,typ,val) typ val #endif #endif /* Declare an aligned array on the stack, for situations where the * stack pointer may not have the alignment we expect. Creates an * array with a modified name, then defines val to be a pointer, and * aligns that pointer within the array. */ #define DECLARE_ALIGNED_ARRAY(a,typ,val,n)\ typ val##_[(n)+(a)/sizeof(typ)+1];\ typ *val = (typ*)((((intptr_t)val##_)+(a)-1)&((intptr_t)-(a)))
/* Indicates that the usage of the specified variable has been
* audited to assure that it's safe to use uninitialized. Silences
* 'may be used uninitialized' warnings on gcc.
*/
#if defined(__GNUC__) && __GNUC__
#define UNINITIALIZED_IS_SAFE(x) x=x
#else
#define UNINITIALIZED_IS_SAFE(x) x
#endif
---- End code block ----------------------------------------
20.11. modemv.c
---- Begin code block --------------------------------------
/*
* Copyright (c) 2010, 2011, Google Inc. 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 "dixie.h"
#include "modemv_data.h"
#include <stdlib.h>
#include <assert.h>
struct mv_clamp_rect
{
int to_left, to_right, to_top, to_bottom;
};
static union mv
clamp_mv(union mv raw, const struct mv_clamp_rect *bounds)
{
union mv newmv;
newmv.d.x = (raw.d.x < bounds->to_left)
? bounds->to_left : raw.d.x;
newmv.d.x = (raw.d.x > bounds->to_right)
? bounds->to_right : newmv.d.x;
newmv.d.y = (raw.d.y < bounds->to_top)
? bounds->to_top : raw.d.y;
newmv.d.y = (raw.d.y > bounds->to_bottom)
? bounds->to_bottom : newmv.d.y;
return newmv;
}
static int
read_segment_id(struct bool_decoder *bool,
struct vp8_segment_hdr *seg)
{
return bool_get(bool, seg->tree_probs[0])
? 2 + bool_get(bool, seg->tree_probs[2])
: bool_get(bool, seg->tree_probs[1]);
}
static enum prediction_mode
above_block_mode(const struct mb_info *this,
const struct mb_info *above,
unsigned int b)
{
if (b < 4)
{
switch (above->base.y_mode)
{
case DC_PRED:
return B_DC_PRED;
case V_PRED:
return B_VE_PRED;
case H_PRED:
return B_HE_PRED;
case TM_PRED:
return B_TM_PRED;
case B_PRED:
return above->split.modes[b+12];
default:
assert(0);
}
}
return this->split.modes[b-4];
}
static enum prediction_mode
left_block_mode(const struct mb_info *this,
const struct mb_info *left,
unsigned int b)
{
if (!(b & 3))
{
switch (left->base.y_mode)
{
case DC_PRED:
return B_DC_PRED;
case V_PRED:
return B_VE_PRED;
case H_PRED:
return B_HE_PRED;
case TM_PRED:
return B_TM_PRED;
case B_PRED:
return left->split.modes[b+3];
default:
assert(0);
}
}
return this->split.modes[b-1];
}
static void
decode_kf_mb_mode(struct mb_info *this,
struct mb_info *left,
struct mb_info *above,
struct bool_decoder *bool)
{
int y_mode, uv_mode;
y_mode = bool_read_tree(bool, kf_y_mode_tree, kf_y_mode_probs);
if (y_mode == B_PRED)
{
unsigned int i;
for (i = 0; i < 16; i++)
{
enum prediction_mode a = above_block_mode(this, above,
i);
enum prediction_mode l = left_block_mode(this, left, i);
enum prediction_mode b;
b = bool_read_tree(bool, b_mode_tree,
kf_b_mode_probs[a][l]);
this->split.modes[i] = b;
}
}
uv_mode = bool_read_tree(bool, uv_mode_tree, kf_uv_mode_probs);
this->base.y_mode = y_mode;
this->base.uv_mode = uv_mode;
this->base.mv.raw = 0;
this->base.ref_frame = 0;
}
static void
decode_intra_mb_mode(struct mb_info *this,
struct vp8_entropy_hdr *hdr,
struct bool_decoder *bool)
{
/* Like decode_kf_mb_mode, but with probabilities transmitted in
* the bitstream and no context on the above/left block mode.
*/
int y_mode, uv_mode;
y_mode = bool_read_tree(bool, y_mode_tree, hdr->y_mode_probs);
if (y_mode == B_PRED)
{
unsigned int i;
for (i = 0; i < 16; i++)
{
enum prediction_mode b;
b = bool_read_tree(bool, b_mode_tree,
default_b_mode_probs);
this->split.modes[i] = b;
}
}
uv_mode = bool_read_tree(bool, uv_mode_tree, hdr->uv_mode_probs);
this->base.y_mode = y_mode;
this->base.uv_mode = uv_mode;
this->base.mv.raw = 0;
this->base.ref_frame = CURRENT_FRAME;
}
static int
read_mv_component(struct bool_decoder *bool,
const unsigned char mvc[MV_PROB_CNT])
{
enum {IS_SHORT, SIGN, SHORT, BITS = SHORT + 8 - 1,
LONG_WIDTH = 10};
int x = 0;
if (bool_get(bool, mvc[IS_SHORT])) /* Large */
{
int i = 0;
for (i = 0; i < 3; i++)
x += bool_get(bool, mvc[BITS + i]) << i;
/* Skip bit 3, which is sometimes implicit */
for (i = LONG_WIDTH - 1; i > 3; i--)
x += bool_get(bool, mvc[BITS + i]) << i;
if (!(x & 0xFFF0) || bool_get(bool, mvc[BITS + 3]))
x += 8;
}
else /* small */
x = bool_read_tree(bool, small_mv_tree, mvc + SHORT);
if (x && bool_get(bool, mvc[SIGN]))
x = -x;
return x << 1;
}
static mv_t
above_block_mv(const struct mb_info *this,
const struct mb_info *above,
unsigned int b)
{
if (b < 4)
{
if (above->base.y_mode == SPLITMV)
return above->split.mvs[b+12];
return above->base.mv;
}
return this->split.mvs[b-4];
}
static mv_t
left_block_mv(const struct mb_info *this,
const struct mb_info *left,
unsigned int b)
{
if (!(b & 3))
{
if (left->base.y_mode == SPLITMV)
return left->split.mvs[b+3];
return left->base.mv;
}
return this->split.mvs[b-1];
}
static enum prediction_mode
submv_ref(struct bool_decoder *bool, union mv l, union mv a)
{
enum subblock_mv_ref
{
SUBMVREF_NORMAL,
SUBMVREF_LEFT_ZED,
SUBMVREF_ABOVE_ZED,
SUBMVREF_LEFT_ABOVE_SAME,
SUBMVREF_LEFT_ABOVE_ZED
};
int lez = !(l.raw);
int aez = !(a.raw);
int lea = l.raw == a.raw;
enum subblock_mv_ref ctx = SUBMVREF_NORMAL;
if (lea && lez)
ctx = SUBMVREF_LEFT_ABOVE_ZED;
else if (lea)
ctx = SUBMVREF_LEFT_ABOVE_SAME;
else if (aez)
ctx = SUBMVREF_ABOVE_ZED;
else if (lez)
ctx = SUBMVREF_LEFT_ZED;
return bool_read_tree(bool, submv_ref_tree,
submv_ref_probs2[ctx]);
}
static void
read_mv(struct bool_decoder *bool,
union mv *mv,
mv_component_probs_t mvc[2])
{
mv->d.y = read_mv_component(bool, mvc[0]);
mv->d.x = read_mv_component(bool, mvc[1]);
}
static void
mv_bias(const struct mb_info *mb,
const unsigned int sign_bias[3],
enum reference_frame ref_frame,
union mv *mv)
{
if (sign_bias[mb->base.ref_frame] ^ sign_bias[ref_frame])
{
mv->d.x *= -1;
mv->d.y *= -1;
}
}
enum near_mv_v
{
CNT_BEST = 0,
CNT_ZEROZERO = 0,
CNT_NEAREST,
CNT_NEAR,
CNT_SPLITMV
};
static void
find_near_mvs(const struct mb_info *this,
const struct mb_info *left,
const struct mb_info *above,
const unsigned int sign_bias[3],
union mv near_mvs[4],
int cnt[4])
{
const struct mb_info *aboveleft = above - 1;
union mv *mv = near_mvs;
int *cntx = cnt;
/* Zero accumulators */
mv[0].raw = mv[1].raw = mv[2].raw = 0;
cnt[0] = cnt[1] = cnt[2] = cnt[3] = 0;
/* Process above */
if (above->base.ref_frame != CURRENT_FRAME)
{
if (above->base.mv.raw)
{
(++mv)->raw = above->base.mv.raw;
mv_bias(above, sign_bias, this->base.ref_frame, mv);
++cntx;
}
*cntx += 2;
}
/* Process left */
if (left->base.ref_frame != CURRENT_FRAME)
{
if (left->base.mv.raw)
{
union mv this_mv;
this_mv.raw = left->base.mv.raw;
mv_bias(left, sign_bias, this->base.ref_frame, &this_mv);
if (this_mv.raw != mv->raw)
{
(++mv)->raw = this_mv.raw;
++cntx;
}
*cntx += 2;
}
else
cnt[CNT_ZEROZERO] += 2;
}
/* Process above left */
if (aboveleft->base.ref_frame != CURRENT_FRAME)
{
if (aboveleft->base.mv.raw)
{
union mv this_mv;
this_mv.raw = aboveleft->base.mv.raw;
mv_bias(aboveleft, sign_bias, this->base.ref_frame,
&this_mv);
if (this_mv.raw != mv->raw)
{
(++mv)->raw = this_mv.raw;
++cntx;
}
*cntx += 1;
}
else
cnt[CNT_ZEROZERO] += 1;
}
/* If we have three distinct MVs ... */
if (cnt[CNT_SPLITMV])
{
/* See if above-left MV can be merged with NEAREST */
if (mv->raw == near_mvs[CNT_NEAREST].raw)
cnt[CNT_NEAREST] += 1;
}
cnt[CNT_SPLITMV] = ((above->base.y_mode == SPLITMV)
+ (left->base.y_mode == SPLITMV)) * 2
+ (aboveleft->base.y_mode == SPLITMV);
/* Swap near and nearest if necessary */
if (cnt[CNT_NEAR] > cnt[CNT_NEAREST])
{
int tmp;
tmp = cnt[CNT_NEAREST];
cnt[CNT_NEAREST] = cnt[CNT_NEAR];
cnt[CNT_NEAR] = tmp;
tmp = near_mvs[CNT_NEAREST].raw;
near_mvs[CNT_NEAREST].raw = near_mvs[CNT_NEAR].raw;
near_mvs[CNT_NEAR].raw = tmp;
}
/* Use near_mvs[CNT_BEST] to store the "best" MV. Note that this
* storage shares the same address as near_mvs[CNT_ZEROZERO].
*/
if (cnt[CNT_NEAREST] >= cnt[CNT_BEST])
near_mvs[CNT_BEST] = near_mvs[CNT_NEAREST];
}
static void
decode_split_mv(struct mb_info *this,
const struct mb_info *left,
const struct mb_info *above,
struct vp8_entropy_hdr *hdr,
union mv *best_mv,
struct bool_decoder *bool)
{
const int *partition;
int j, k, mask, partition_id;
partition_id = bool_read_tree(bool, split_mv_tree,
split_mv_probs);
partition = mv_partitions[partition_id];
this->base.partitioning = partition_id;
for (j = 0, mask = 0; mask < 65535; j++)
{
union mv mv, left_mv, above_mv;
enum prediction_mode subblock_mode;
/* Find the first subblock in this partition. */
for (k = 0; j != partition[k]; k++);
/* Decode the next MV */
left_mv = left_block_mv(this, left, k);
above_mv = above_block_mv(this, above, k);
subblock_mode = submv_ref(bool, left_mv, above_mv);
switch (subblock_mode)
{
case LEFT4X4:
mv = left_mv;
break;
case ABOVE4X4:
mv = above_mv;
break;
case ZERO4X4:
mv.raw = 0;
break;
case NEW4X4:
read_mv(bool, &mv, hdr->mv_probs);
mv.d.x += best_mv->d.x;
mv.d.y += best_mv->d.y;
break;
default:
assert(0);
}
/* Fill the MVs for this partition */
for (; k < 16; k++)
if (j == partition[k])
{
this->split.mvs[k] = mv;
mask |= 1 << k;
}
}
}
static int
need_mc_border(union mv mv, int l, int t, int b_w, int w, int h)
{
int b, r;
/* Get distance to edge for top-left pixel */
l += (mv.d.x >> 3);
t += (mv.d.y >> 3);
/* Get distance to edge for bottom-right pixel */
r = w - (l + b_w);
b = h - (t + b_w);
return (l >> 1 < 2 || r >> 1 < 3 || t >> 1 < 2 || b >> 1 < 3);
}
static void
decode_mvs(struct vp8_decoder_ctx *ctx,
struct mb_info *this,
const struct mb_info *left,
const struct mb_info *above,
const struct mv_clamp_rect *bounds,
struct bool_decoder *bool)
{
struct vp8_entropy_hdr *hdr = &ctx->entropy_hdr;
union mv near_mvs[4];
union mv clamped_best_mv;
int mv_cnts[4];
unsigned char probs[4];
enum {BEST, NEAREST, NEAR};
int x, y, w, h, b;
this->base.ref_frame = bool_get(bool, hdr->prob_last)
? 2 + bool_get(bool, hdr->prob_gf)
: 1;
find_near_mvs(this, this - 1, above,
ctx->reference_hdr.sign_bias, near_mvs, mv_cnts);
probs[0] = mv_counts_to_probs[mv_cnts[0]][0];
probs[1] = mv_counts_to_probs[mv_cnts[1]][1];
probs[2] = mv_counts_to_probs[mv_cnts[2]][2];
probs[3] = mv_counts_to_probs[mv_cnts[3]][3];
this->base.y_mode = bool_read_tree(bool, mv_ref_tree, probs);
this->base.uv_mode = this->base.y_mode;
this->base.need_mc_border = 0;
x = (-bounds->to_left - 128) >> 3;
y = (-bounds->to_top - 128) >> 3;
w = ctx->mb_cols * 16;
h = ctx->mb_rows * 16;
switch (this->base.y_mode)
{
case NEARESTMV:
this->base.mv = clamp_mv(near_mvs[NEAREST], bounds);
break;
case NEARMV:
this->base.mv = clamp_mv(near_mvs[NEAR], bounds);
break;
case ZEROMV:
this->base.mv.raw = 0;
return; //skip need_mc_border check
case NEWMV:
clamped_best_mv = clamp_mv(near_mvs[BEST], bounds);
read_mv(bool, &this->base.mv, hdr->mv_probs);
this->base.mv.d.x += clamped_best_mv.d.x;
this->base.mv.d.y += clamped_best_mv.d.y;
break;
case SPLITMV:
{
union mv chroma_mv[4] = {{{0}}};
clamped_best_mv = clamp_mv(near_mvs[BEST], bounds);
decode_split_mv(this, left, above, hdr, &clamped_best_mv,
bool);
this->base.mv = this->split.mvs[15];
for (b = 0; b < 16; b++)
{
chroma_mv[(b>>1&1) + (b>>2&2)].d.x +=
this->split.mvs[b].d.x;
chroma_mv[(b>>1&1) + (b>>2&2)].d.y +=
this->split.mvs[b].d.y;
if (need_mc_border(this->split.mvs[b],
x + (b & 3) * 4, y + (b & ~3), 4, w, h))
{
this->base.need_mc_border = 1;
break;
}
}
for (b = 0; b < 4; b++)
{
chroma_mv[b].d.x += 4 + 8 * (chroma_mv[b].d.x >> 31);
chroma_mv[b].d.y += 4 + 8 * (chroma_mv[b].d.y >> 31);
chroma_mv[b].d.x /= 4;
chroma_mv[b].d.y /= 4;
//note we're passing in non-subsampled coordinates
if (need_mc_border(chroma_mv[b],
x + (b & 1) * 8, y + (b >> 1) * 8, 16, w, h))
{
this->base.need_mc_border = 1;
break;
}
}
return; //skip need_mc_border check
}
default:
assert(0);
}
if (need_mc_border(this->base.mv, x, y, 16, w, h))
this->base.need_mc_border = 1;
}
void
vp8_dixie_modemv_process_row(struct vp8_decoder_ctx *ctx,
struct bool_decoder *bool,
int row,
int start_col,
int num_cols)
{
struct mb_info *above, *this;
unsigned int col;
struct mv_clamp_rect bounds;
this = ctx->mb_info_rows[row] + start_col;
above = ctx->mb_info_rows[row - 1] + start_col;
/* Calculate the eighth-pel MV bounds using a 1 MB border. */
bounds.to_left = -((start_col + 1) << 7);
bounds.to_right = (ctx->mb_cols - start_col) << 7;
bounds.to_top = -((row + 1) << 7);
bounds.to_bottom = (ctx->mb_rows - row) << 7;
for (col = start_col; col < start_col + num_cols; col++)
{
if (ctx->segment_hdr.update_map)
this->base.segment_id = read_segment_id(bool,
&ctx->segment_hdr);
if (ctx->entropy_hdr.coeff_skip_enabled)
this->base.skip_coeff = bool_get(bool,
ctx->entropy_hdr.coeff_skip_prob);
if (ctx->frame_hdr.is_keyframe)
{
if (!ctx->segment_hdr.update_map)
this->base.segment_id = 0;
decode_kf_mb_mode(this, this - 1, above, bool);
}
else
{
if (bool_get(bool, ctx->entropy_hdr.prob_inter))
decode_mvs(ctx, this, this - 1, above, &bounds,
bool);
else
decode_intra_mb_mode(this, &ctx->entropy_hdr, bool);
bounds.to_left -= 16 << 3;
bounds.to_right -= 16 << 3;
}
/* Advance to next mb */
this++;
above++;
}
}
void
vp8_dixie_modemv_init(struct vp8_decoder_ctx *ctx)
{
unsigned int mbi_w, mbi_h, i;
struct mb_info *mbi;
mbi_w = ctx->mb_cols + 1; /* For left border col */
mbi_h = ctx->mb_rows + 1; /* For above border row */
if (ctx->frame_hdr.frame_size_updated)
{
free(ctx->mb_info_storage);
ctx->mb_info_storage = NULL;
free(ctx->mb_info_rows_storage);
ctx->mb_info_rows_storage = NULL;
}
if (!ctx->mb_info_storage)
ctx->mb_info_storage = calloc(mbi_w * mbi_h,
sizeof(*ctx->mb_info_storage));
if (!ctx->mb_info_rows_storage)
ctx->mb_info_rows_storage = calloc(mbi_h,
sizeof(*ctx->mb_info_rows_storage));
/* Set up row pointers */
mbi = ctx->mb_info_storage + 1;
for (i = 0; i < mbi_h; i++)
{
ctx->mb_info_rows_storage[i] = mbi;
mbi += mbi_w;
}
ctx->mb_info_rows = ctx->mb_info_rows_storage + 1;
}
void
vp8_dixie_modemv_destroy(struct vp8_decoder_ctx *ctx)
{
free(ctx->mb_info_storage);
ctx->mb_info_storage = NULL;
free(ctx->mb_info_rows_storage);
ctx->mb_info_rows_storage = NULL;
}
---- End code block ----------------------------------------
20.12. modemv.h
---- Begin code block --------------------------------------
/*
* Copyright (c) 2010, 2011, Google Inc. 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.
*/
#ifndef MODEMV_H
#define MODEMV_H
void
vp8_dixie_modemv_init(struct vp8_decoder_ctx *ctx);
void
vp8_dixie_modemv_destroy(struct vp8_decoder_ctx *ctx);
void
vp8_dixie_modemv_process_row(struct vp8_decoder_ctx *ctx,
struct bool_decoder *bool,
int row,
int start_col,
int num_cols);
#endif
---- End code block ----------------------------------------
(next page on part 8)
