/* Hierarchical (iterative) OpenCL lowres motion search */
inline int find_downscale_mb_xy( int x, int y, int mb_width, int mb_height )
{
/* edge macroblocks might not have a direct descendant, use nearest */
x = select( x >> 1, (x - (mb_width&1)) >> 1, x == mb_width-1 )
y = select( y >> 1, (y - (mb_height&1)) >> 1, y == mb_height-1 )
return (mb_width>>1) * y + x
}
/* Four threads calculate an 8x8 SAD. Each does two rows */
int sad_8x8_ii_coop4( read_only image2d_t fenc, int2 fencpos, read_only image2d_t fref, int2 frefpos, int idx, local int16_t *costs )
{
frefpos.y += idx << 1
fencpos.y += idx << 1
int cost = 0
if( frefpos.x < 0 )
{
/* slow path when MV goes past left edge. The GPU clamps reads from
* (-1, 0) to (0,0), so you get pixels [0, 1, 2, 3] when what you really
* want are [0, 0, 1, 2]
*/
for( int y = 0
{
for( int x = 0
{
pixel enc = read_imageui( fenc, sampler, fencpos + (int2)(x, y) ).s0
pixel ref = read_imageui( fref, sampler, frefpos + (int2)(x, y) ).s0
cost += abs_diff( enc, ref )
}
}
}
else
{
uint4 enc, ref, costs = 0
enc = read_imageui( fenc, sampler, fencpos )
ref = read_imageui( fref, sampler, frefpos )
costs += abs_diff( enc, ref )
enc = read_imageui( fenc, sampler, fencpos + (int2)(4, 0) )
ref = read_imageui( fref, sampler, frefpos + (int2)(4, 0) )
costs += abs_diff( enc, ref )
enc = read_imageui( fenc, sampler, fencpos + (int2)(0, 1) )
ref = read_imageui( fref, sampler, frefpos + (int2)(0, 1) )
costs += abs_diff( enc, ref )
enc = read_imageui( fenc, sampler, fencpos + (int2)(4, 1) )
ref = read_imageui( fref, sampler, frefpos + (int2)(4, 1) )
costs += abs_diff( enc, ref )
cost = costs.s0 + costs.s1 + costs.s2 + costs.s3
}
costs[idx] = cost
return costs[0] + costs[1] + costs[2] + costs[3]
}
/* One thread performs 8x8 SAD */
int sad_8x8_ii( read_only image2d_t fenc, int2 fencpos, read_only image2d_t fref, int2 frefpos )
{
if( frefpos.x < 0 )
{
/* slow path when MV goes past left edge */
int cost = 0
for( int y = 0
{
for( int x = 0
{
uint enc = read_imageui( fenc, sampler, fencpos + (int2)(x, y) ).s0
uint ref = read_imageui( fref, sampler, frefpos + (int2)(x, y) ).s0
cost += abs_diff( enc, ref )
}
}
return cost
}
else
{
uint4 enc, ref, cost = 0
for( int y = 0
{
for( int x = 0
{
enc = read_imageui( fenc, sampler, fencpos + (int2)(x, y) )
ref = read_imageui( fref, sampler, frefpos + (int2)(x, y) )
cost += abs_diff( enc, ref )
}
}
return cost.s0 + cost.s1 + cost.s2 + cost.s3
}
}
/*
* hierarchical motion estimation
*
* Each kernel launch is a single iteration
*
* MB per work group is determined by lclx / 4 * lcly
*
* global launch dimensions: [mb_width * 4, mb_height]
*/
kernel void hierarchical_motion( read_only image2d_t fenc,
read_only image2d_t fref,
const global short2 *in_mvs,
global short2 *out_mvs,
global int16_t *out_mv_costs,
global short2 *mvp_buffer,
local int16_t *cost_local,
local short2 *mvc_local,
int mb_width,
int lambda,
int me_range,
int scale,
int b_shift_index,
int b_first_iteration,
int b_reverse_references )
{
int mb_x = get_global_id( 0 ) >> 2
if( mb_x >= mb_width )
return
int mb_height = get_global_size( 1 )
int mb_i = get_global_id( 0 ) & 3
int mb_y = get_global_id( 1 )
int mb_xy = mb_y * mb_width + mb_x
const int mb_size = 8
int2 coord = (int2)(mb_x, mb_y) * mb_size
const int mb_in_group = get_local_id( 1 ) * (get_local_size( 0 ) >> 2) + (get_local_id( 0 ) >> 2)
cost_local += 4 * mb_in_group
int i_mvc = 0
mvc_local += 4 * mb_in_group
mvc_local[mb_i] = 0
int2 mvp =0
if( !b_first_iteration )
{
#define MVC( DX, DY )\
{\
int px = mb_x + DX
int py = mb_y + DY
mvc_local[i_mvc] = b_shift_index ? in_mvs[find_downscale_mb_xy( px, py, mb_width, mb_height )] : \
in_mvs[mb_width * py + px]
mvc_local[i_mvc] >>= (short) scale
i_mvc++
}
/* Find MVP from median of MVCs */
if( b_reverse_references )
{
/* odd iterations: derive MVP from down and right */
if( mb_x < mb_width - 1 )
MVC( 1, 0 )
if( mb_y < mb_height - 1 )
{
MVC( 0, 1 )
if( mb_x > b_shift_index )
MVC( -1, 1 )
if( mb_x < mb_width - 1 )
MVC( 1, 1 )
}
}
else
{
/* even iterations: derive MVP from up and left */
if( mb_x > 0 )
MVC( -1, 0 )
if( mb_y > 0 )
{
MVC( 0, -1 )
if( mb_x < mb_width - 1 )
MVC( 1, -1 )
if( mb_x > b_shift_index )
MVC( -1, -1 )
}
}
#undef MVC
mvp = (i_mvc <= 1) ? convert_int2_sat(mvc_local[0]) : x264_median_mv( mvc_local[0], mvc_local[1], mvc_local[2] )
}
/* current mvp matches the previous mvp and we have not changed scale. We know
* we're going to arrive at the same MV again, so just copy the previous
* result to our output. */
if( !b_shift_index && mvp.x == mvp_buffer[mb_xy].x && mvp.y == mvp_buffer[mb_xy].y )
{
out_mvs[mb_xy] = in_mvs[mb_xy]
return
}
mvp_buffer[mb_xy] = convert_short2_sat(mvp)
int2 mv_min = -mb_size * (int2)(mb_x, mb_y) - 4
int2 mv_max = mb_size * ((int2)(mb_width, mb_height) - (int2)(mb_x, mb_y) - 1) + 4
int2 bestmv = clamp(mvp, mv_min, mv_max)
int2 refcrd = coord + bestmv
/* measure cost at bestmv */
int bcost = sad_8x8_ii_coop4( fenc, coord, fref, refcrd, mb_i, cost_local ) +
lambda * mv_cost( abs_diff( bestmv, mvp ) << (2 + scale) )
do
{
/* measure costs at offsets from bestmv */
refcrd = coord + bestmv + dia_offs[mb_i]
int2 trymv = bestmv + dia_offs[mb_i]
int cost = sad_8x8_ii( fenc, coord, fref, refcrd ) +
lambda * mv_cost( abs_diff( trymv, mvp ) << (2 + scale) )
cost_local[mb_i] = (cost<<2) | mb_i;
cost = min( cost_local[0], min( cost_local[1], min( cost_local[2], cost_local[3] ) ) )
if( (cost >> 2) >= bcost )
break
bestmv += dia_offs[cost&3]
bcost = cost>>2
if( bestmv.x >= mv_max.x || bestmv.x <= mv_min.x || bestmv.y >= mv_max.y || bestmv.y <= mv_min.y )
break
}
while( --me_range > 0 )
int2 trymv = 0, diff = 0
#define COST_MV_NO_PAD( L )\
trymv = clamp( trymv, mv_min, mv_max )
diff = convert_int2_sat(abs_diff( mvp, trymv ))
if( diff.x > 1 || diff.y > 1 ) {\
int2 refcrd = coord + trymv
int cost = sad_8x8_ii_coop4( fenc, coord, fref, refcrd, mb_i, cost_local ) +\
L * mv_cost( abs_diff( trymv, mvp ) << (2 + scale) )
if( cost < bcost ) { bcost = cost
COST_MV_NO_PAD( 0 )
if( !b_first_iteration )
{
/* try cost at previous iteration's MV, if MVP was too far away */
int2 prevmv = b_shift_index ? convert_int2_sat(in_mvs[find_downscale_mb_xy( mb_x, mb_y, mb_width, mb_height )]) : convert_int2_sat(in_mvs[mb_xy])
prevmv >>= scale
trymv = prevmv
COST_MV_NO_PAD( lambda )
}
for( int i = 0
{
/* try cost at each candidate MV, if MVP was too far away */
trymv = convert_int2_sat( mvc_local[i] )
COST_MV_NO_PAD( lambda )
}
if( mb_i == 0 )
{
bestmv <<= scale
out_mvs[mb_xy] = convert_short2_sat(bestmv)
out_mv_costs[mb_xy] = min( bcost, LOWRES_COST_MASK )
}
}