ref: e65f5987f6eea95bfbb0876cc0a966d1d82f5841
dir: /vp8/encoder/segmentation.c/
/*
* Copyright (c) 2012 The WebM 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 "limits.h"
#include "vpx_mem/vpx_mem.h"
#include "segmentation.h"
#include "vp8/common/pred_common.h"
void vp8_update_gf_useage_maps(VP8_COMP *cpi, VP8_COMMON *cm, MACROBLOCK *x)
{
int mb_row, mb_col;
MODE_INFO *this_mb_mode_info = cm->mi;
x->gf_active_ptr = (signed char *)cpi->gf_active_flags;
if ((cm->frame_type == KEY_FRAME) || (cm->refresh_golden_frame))
{
// Reset Gf useage monitors
vpx_memset(cpi->gf_active_flags, 1, (cm->mb_rows * cm->mb_cols));
cpi->gf_active_count = cm->mb_rows * cm->mb_cols;
}
else
{
// for each macroblock row in image
for (mb_row = 0; mb_row < cm->mb_rows; mb_row++)
{
// for each macroblock col in image
for (mb_col = 0; mb_col < cm->mb_cols; mb_col++)
{
// If using golden then set GF active flag if not already set.
// If using last frame 0,0 mode then leave flag as it is
// else if using non 0,0 motion or intra modes then clear
// flag if it is currently set
if ((this_mb_mode_info->mbmi.ref_frame == GOLDEN_FRAME) ||
(this_mb_mode_info->mbmi.ref_frame == ALTREF_FRAME))
{
if (*(x->gf_active_ptr) == 0)
{
*(x->gf_active_ptr) = 1;
cpi->gf_active_count ++;
}
}
else if ((this_mb_mode_info->mbmi.mode != ZEROMV) &&
*(x->gf_active_ptr))
{
*(x->gf_active_ptr) = 0;
cpi->gf_active_count--;
}
x->gf_active_ptr++; // Step onto next entry
this_mb_mode_info++; // skip to next mb
}
// this is to account for the border
this_mb_mode_info++;
}
}
}
void vp8_enable_segmentation(VP8_PTR ptr)
{
VP8_COMP *cpi = (VP8_COMP *)(ptr);
// Set the appropriate feature bit
cpi->mb.e_mbd.segmentation_enabled = 1;
cpi->mb.e_mbd.update_mb_segmentation_map = 1;
cpi->mb.e_mbd.update_mb_segmentation_data = 1;
}
void vp8_disable_segmentation(VP8_PTR ptr)
{
VP8_COMP *cpi = (VP8_COMP *)(ptr);
// Clear the appropriate feature bit
cpi->mb.e_mbd.segmentation_enabled = 0;
}
void vp8_set_segmentation_map(VP8_PTR ptr,
unsigned char *segmentation_map)
{
VP8_COMP *cpi = (VP8_COMP *)(ptr);
// Copy in the new segmentation map
vpx_memcpy( cpi->segmentation_map, segmentation_map,
(cpi->common.mb_rows * cpi->common.mb_cols) );
// Signal that the map should be updated.
cpi->mb.e_mbd.update_mb_segmentation_map = 1;
cpi->mb.e_mbd.update_mb_segmentation_data = 1;
}
void vp8_set_segment_data(VP8_PTR ptr,
signed char *feature_data,
unsigned char abs_delta)
{
VP8_COMP *cpi = (VP8_COMP *)(ptr);
cpi->mb.e_mbd.mb_segment_abs_delta = abs_delta;
vpx_memcpy(cpi->mb.e_mbd.segment_feature_data, feature_data,
sizeof(cpi->mb.e_mbd.segment_feature_data));
// TBD ?? Set the feature mask
// vpx_memcpy(cpi->mb.e_mbd.segment_feature_mask, 0,
// sizeof(cpi->mb.e_mbd.segment_feature_mask));
}
// Based on set of segment counts calculate a probability tree
static void calc_segtree_probs( MACROBLOCKD * xd,
int * segcounts,
vp8_prob * segment_tree_probs )
{
int count1,count2;
int tot_count;
int i;
// Blank the strtucture to start with
vpx_memset(segment_tree_probs, 0, sizeof(segment_tree_probs));
// Total count for all segments
count1 = segcounts[0] + segcounts[1];
count2 = segcounts[2] + segcounts[3];
tot_count = count1 + count2;
// Work out probabilities of each segment
if (tot_count)
segment_tree_probs[0] = (count1 * 255) / tot_count;
if (count1 > 0)
segment_tree_probs[1] = (segcounts[0] * 255) / count1;
if (count2 > 0)
segment_tree_probs[2] = (segcounts[2] * 255) / count2;
// Clamp probabilities to minimum allowed value
for (i = 0; i < MB_FEATURE_TREE_PROBS; i++)
{
if (segment_tree_probs[i] == 0)
segment_tree_probs[i] = 1;
}
}
// Based on set of segment counts and probabilities calculate a cost estimate
static int cost_segmap( MACROBLOCKD * xd,
int * segcounts,
vp8_prob * probs )
{
int cost;
int count1,count2;
// Cost the top node of the tree
count1 = segcounts[0] + segcounts[1];
count2 = segcounts[2] + segcounts[3];
cost = count1 * vp8_cost_zero(probs[0]) +
count2 * vp8_cost_one(probs[0]);
// Now add the cost of each individual segment branch
if (count1 > 0)
cost += segcounts[0] * vp8_cost_zero(probs[1]) +
segcounts[1] * vp8_cost_one(probs[1]);
if (count2 > 0)
cost += segcounts[2] * vp8_cost_zero(probs[2]) +
segcounts[3] * vp8_cost_one(probs[2]) ;
return cost;
}
void choose_segmap_coding_method( VP8_COMP *cpi )
{
VP8_COMMON *const cm = & cpi->common;
MACROBLOCKD *const xd = & cpi->mb.e_mbd;
int i;
int tot_count;
int no_pred_cost;
int t_pred_cost = INT_MAX;
int pred_context;
int mb_row, mb_col;
int segmap_index = 0;
unsigned char segment_id;
int temporal_predictor_count[PREDICTION_PROBS][2];
int no_pred_segcounts[MAX_MB_SEGMENTS];
int t_unpred_seg_counts[MAX_MB_SEGMENTS];
vp8_prob no_pred_tree[MB_FEATURE_TREE_PROBS];
vp8_prob t_pred_tree[MB_FEATURE_TREE_PROBS];
vp8_prob t_nopred_prob[PREDICTION_PROBS];
// Set default state for the segment tree probabilities and the
// temporal coding probabilities
vpx_memset(xd->mb_segment_tree_probs, 255,
sizeof(xd->mb_segment_tree_probs));
vpx_memset(cm->segment_pred_probs, 255,
sizeof(cm->segment_pred_probs));
vpx_memset(no_pred_segcounts, 0, sizeof(no_pred_segcounts));
vpx_memset(t_unpred_seg_counts, 0, sizeof(t_unpred_seg_counts));
vpx_memset(temporal_predictor_count, 0, sizeof(temporal_predictor_count));
// First of all generate stats regarding how well the last segment map
// predicts this one
// Initialize macroblock decoder mode info context for the first mb
// in the frame
xd->mode_info_context = cm->mi;
for (mb_row = 0; mb_row < cm->mb_rows; mb_row++)
{
for (mb_col = 0; mb_col < cm->mb_cols; mb_col++)
{
segment_id = xd->mode_info_context->mbmi.segment_id;
// Count the number of hits on each segment with no prediction
no_pred_segcounts[segment_id]++;
// Temporal prediction not allowed on key frames
if (cm->frame_type != KEY_FRAME)
{
// Test to see if the segment id matches the predicted value.
int seg_predicted =
(segment_id == get_pred_mb_segid( cm, segmap_index ));
// Get the segment id prediction context
pred_context =
get_pred_context( cm, xd, PRED_SEG_ID );
// Store the prediction status for this mb and update counts
// as appropriate
set_pred_flag( xd, PRED_SEG_ID, seg_predicted );
temporal_predictor_count[pred_context][seg_predicted]++;
if ( !seg_predicted )
// Update the "unpredicted" segment count
t_unpred_seg_counts[segment_id]++;
}
// Step on to the next mb
xd->mode_info_context++;
// Step on to the next entry in the segment maps
segmap_index++;
}
// this is to account for the border in mode_info_context
xd->mode_info_context++;
}
// Work out probability tree for coding segments without prediction
// and the cost.
calc_segtree_probs( xd, no_pred_segcounts, no_pred_tree );
no_pred_cost = cost_segmap( xd, no_pred_segcounts, no_pred_tree );
// Key frames cannot use temporal prediction
if (cm->frame_type != KEY_FRAME)
{
// Work out probability tree for coding those segments not
// predicted using the temporal method and the cost.
calc_segtree_probs( xd, t_unpred_seg_counts, t_pred_tree );
t_pred_cost = cost_segmap( xd, t_unpred_seg_counts, t_pred_tree );
// Add in the cost of the signalling for each prediction context
for ( i = 0; i < PREDICTION_PROBS; i++ )
{
tot_count = temporal_predictor_count[i][0] +
temporal_predictor_count[i][1];
// Work out the context probabilities for the segment
// prediction flag
if ( tot_count )
{
t_nopred_prob[i] = ( temporal_predictor_count[i][0] * 255 ) /
tot_count;
// Clamp to minimum allowed value
if ( t_nopred_prob[i] < 1 )
t_nopred_prob[i] = 1;
}
else
t_nopred_prob[i] = 1;
// Add in the predictor signaling cost
t_pred_cost += ( temporal_predictor_count[i][0] *
vp8_cost_zero(t_nopred_prob[i]) ) +
( temporal_predictor_count[i][1] *
vp8_cost_one(t_nopred_prob[i]) );
}
}
// Now choose which coding method to use.
if ( t_pred_cost < no_pred_cost )
{
cm->temporal_update = 1;
vpx_memcpy( xd->mb_segment_tree_probs,
t_pred_tree, sizeof(t_pred_tree) );
vpx_memcpy( &cm->segment_pred_probs,
t_nopred_prob, sizeof(t_nopred_prob) );
}
else
{
cm->temporal_update = 0;
vpx_memcpy( xd->mb_segment_tree_probs,
no_pred_tree, sizeof(no_pred_tree) );
}
}