+/* makes a non-h264 weight (i.e. fix7), into an h264 weight */
+static void x264_weight_get_h264( int weight_nonh264, int offset, x264_weight_t *w )
+{
+ w->i_offset = offset;
+ w->i_denom = 7;
+ w->i_scale = weight_nonh264;
+ while( w->i_denom > 0 && (w->i_scale > 127 || !(w->i_scale & 1)) )
+ {
+ w->i_denom--;
+ w->i_scale >>= 1;
+ }
+ w->i_scale = X264_MIN( w->i_scale, 127 );
+}
+
+static NOINLINE pixel *x264_weight_cost_init_luma( x264_t *h, x264_frame_t *fenc, x264_frame_t *ref, pixel *dest )
+{
+ int ref0_distance = fenc->i_frame - ref->i_frame - 1;
+ /* Note: this will never run during lookahead as weights_analyse is only called if no
+ * motion search has been done. */
+ if( fenc->lowres_mvs[0][ref0_distance][0][0] != 0x7FFF )
+ {
+ int i_stride = fenc->i_stride_lowres;
+ int i_lines = fenc->i_lines_lowres;
+ int i_width = fenc->i_width_lowres;
+ int i_mb_xy = 0;
+ pixel *p = dest;
+
+ for( int y = 0; y < i_lines; y += 8, p += i_stride*8 )
+ for( int x = 0; x < i_width; x += 8, i_mb_xy++ )
+ {
+ int mvx = fenc->lowres_mvs[0][ref0_distance][i_mb_xy][0];
+ int mvy = fenc->lowres_mvs[0][ref0_distance][i_mb_xy][1];
+ h->mc.mc_luma( p+x, i_stride, ref->lowres, i_stride,
+ mvx+(x<<2), mvy+(y<<2), 8, 8, weight_none );
+ }
+ x264_emms();
+ return dest;
+ }
+ x264_emms();
+ return ref->lowres[0];
+}
+
+/* How data is organized for chroma weightp:
+ * [U: ref] [U: fenc]
+ * [V: ref] [V: fenc]
+ * fenc = ref + offset
+ * v = u + stride * chroma height
+ * We'll need more room if we do 4:2:2 or 4:4:4. */
+
+static NOINLINE void x264_weight_cost_init_chroma( x264_t *h, x264_frame_t *fenc, x264_frame_t *ref, pixel *dstu, pixel *dstv )
+{
+ int ref0_distance = fenc->i_frame - ref->i_frame - 1;
+ int i_stride = fenc->i_stride[1];
+ int i_offset = i_stride / 2;
+ int i_lines = fenc->i_lines[1];
+ int i_width = fenc->i_width[1];
+ int cw = h->mb.i_mb_width << 3;
+ int ch = h->mb.i_mb_height << 3;
+
+ if( fenc->lowres_mvs[0][ref0_distance][0][0] != 0x7FFF )
+ {
+ for( int y = 0, mb_xy = 0, pel_offset_y = 0; y < i_lines; y += 8, pel_offset_y = y*i_stride )
+ for( int x = 0, pel_offset_x = 0; x < i_width; x += 8, mb_xy++, pel_offset_x += 8 )
+ {
+ pixel *pixu = dstu + pel_offset_y + pel_offset_x;
+ pixel *pixv = dstv + pel_offset_y + pel_offset_x;
+ pixel *src1 = ref->plane[1] + pel_offset_y + pel_offset_x*2; /* NV12 */
+ int mvx = fenc->lowres_mvs[0][ref0_distance][mb_xy][0];
+ int mvy = fenc->lowres_mvs[0][ref0_distance][mb_xy][1];
+ h->mc.mc_chroma( pixu, pixv, i_stride, src1, i_stride, mvx, mvy, 8, 8 );
+ }
+ }
+ else
+ h->mc.plane_copy_deinterleave( dstu, i_stride, dstv, i_stride, ref->plane[1], i_stride, cw, ch );
+ h->mc.plane_copy_deinterleave( dstu+i_offset, i_stride, dstv+i_offset, i_stride, fenc->plane[1], i_stride, cw, ch );
+ x264_emms();
+}
+
+static int x264_weight_slice_header_cost( x264_t *h, x264_weight_t *w, int b_chroma )
+{
+ /* Add cost of weights in the slice header. */
+ int lambda = x264_lambda_tab[X264_LOOKAHEAD_QP];
+ int numslices;
+ if( h->param.i_slice_count )
+ numslices = h->param.i_slice_count;
+ else if( h->param.i_slice_max_mbs )
+ numslices = (h->mb.i_mb_width * h->mb.i_mb_height + h->param.i_slice_max_mbs-1) / h->param.i_slice_max_mbs;
+ else
+ numslices = 1;
+ /* FIXME: find a way to account for --slice-max-size?
+ * Multiply by 2 as there will be a duplicate. 10 bits added as if there is a weighted frame, then an additional duplicate is used.
+ * Cut denom cost in half if chroma, since it's shared between the two chroma planes. */
+ int denom_cost = bs_size_ue( w[0].i_denom ) * (2 - b_chroma);
+ return lambda * numslices * ( 10 + denom_cost + 2 * (bs_size_se( w[0].i_scale ) + bs_size_se( w[0].i_offset )) );
+}
+
+static NOINLINE unsigned int x264_weight_cost_luma( x264_t *h, x264_frame_t *fenc, pixel *src, x264_weight_t *w )
+{
+ unsigned int cost = 0;
+ int i_stride = fenc->i_stride_lowres;
+ int i_lines = fenc->i_lines_lowres;
+ int i_width = fenc->i_width_lowres;
+ pixel *fenc_plane = fenc->lowres[0];
+ ALIGNED_ARRAY_16( pixel, buf,[8*8] );
+ int pixoff = 0;
+ int i_mb = 0;
+
+ if( w )
+ {
+ for( int y = 0; y < i_lines; y += 8, pixoff = y*i_stride )
+ for( int x = 0; x < i_width; x += 8, i_mb++, pixoff += 8)
+ {
+ w->weightfn[8>>2]( buf, 8, &src[pixoff], i_stride, w, 8 );
+ cost += X264_MIN( h->pixf.mbcmp[PIXEL_8x8]( buf, 8, &fenc_plane[pixoff], i_stride ), fenc->i_intra_cost[i_mb] );
+ }
+ cost += x264_weight_slice_header_cost( h, w, 0 );
+ }
+ else
+ for( int y = 0; y < i_lines; y += 8, pixoff = y*i_stride )
+ for( int x = 0; x < i_width; x += 8, i_mb++, pixoff += 8 )
+ cost += X264_MIN( h->pixf.mbcmp[PIXEL_8x8]( &src[pixoff], i_stride, &fenc_plane[pixoff], i_stride ), fenc->i_intra_cost[i_mb] );
+ x264_emms();
+ return cost;
+}
+
+static NOINLINE unsigned int x264_weight_cost_chroma( x264_t *h, x264_frame_t *fenc, pixel *ref, x264_weight_t *w )
+{
+ unsigned int cost = 0;
+ int i_stride = fenc->i_stride[1];
+ int i_offset = i_stride / 2;
+ int i_lines = fenc->i_lines[1];
+ int i_width = fenc->i_width[1];
+ pixel *src = ref + i_offset;
+ ALIGNED_ARRAY_16( pixel, buf, [8*8] );
+ int pixoff = 0;
+ ALIGNED_16( static pixel flat[9] ) = {0,0,0,0,0,0,0,0,1}; //hack for win32
+ if( w )
+ {
+ for( int y = 0; y < i_lines; y += 8, pixoff = y*i_stride )
+ for( int x = 0; x < i_width; x += 8, pixoff += 8 )
+ {
+ w->weightfn[8>>2]( buf, 8, &ref[pixoff], i_stride, w, 8 );
+ /* The naive and seemingly sensible algorithm is to use mbcmp as in luma.
+ * But testing shows that for chroma the DC coefficient is by far the most
+ * important part of the coding cost. Thus a more useful chroma weight is
+ * obtained by comparing each block's DC coefficient instead of the actual
+ * pixels.
+ *
+ * FIXME: add a (faster) asm sum function to replace sad. */
+ cost += abs( h->pixf.sad_aligned[PIXEL_8x8]( buf, 8, flat, 0 ) -
+ h->pixf.sad_aligned[PIXEL_8x8]( &src[pixoff], i_stride, flat, 0 ) );
+ }
+ cost += x264_weight_slice_header_cost( h, w, 1 );
+ }
+ else
+ for( int y = 0; y < i_lines; y += 8, pixoff = y*i_stride )
+ for( int x = 0; x < i_width; x += 8, pixoff += 8 )
+ cost += abs( h->pixf.sad_aligned[PIXEL_8x8]( &ref[pixoff], i_stride, flat, 0 ) -
+ h->pixf.sad_aligned[PIXEL_8x8]( &src[pixoff], i_stride, flat, 0 ) );
+ x264_emms();
+ return cost;
+}
+
+void x264_weights_analyse( x264_t *h, x264_frame_t *fenc, x264_frame_t *ref, int b_lookahead )
+{
+ int i_delta_index = fenc->i_frame - ref->i_frame - 1;
+ /* epsilon is chosen to require at least a numerator of 127 (with denominator = 128) */
+ const float epsilon = 1.f/128.f;
+ x264_weight_t *weights = fenc->weight[0];
+ SET_WEIGHT( weights[0], 0, 1, 0, 0 );
+ SET_WEIGHT( weights[1], 0, 1, 0, 0 );
+ SET_WEIGHT( weights[2], 0, 1, 0, 0 );
+ /* Don't check chroma in lookahead, or if there wasn't a luma weight. */
+ for( int plane = 0; plane <= 2 && !( plane && ( !weights[0].weightfn || b_lookahead ) ); plane++ )
+ {
+ int offset_search;
+ int minoff, minscale, mindenom;
+ unsigned int minscore, origscore;
+ int found;
+ float fenc_var = fenc->i_pixel_ssd[plane] + !ref->i_pixel_ssd[plane];
+ float ref_var = ref->i_pixel_ssd[plane] + !ref->i_pixel_ssd[plane];
+ float guess_scale = sqrtf( fenc_var / ref_var );
+ float fenc_mean = (float)fenc->i_pixel_sum[plane] / (fenc->i_lines[!!plane] * fenc->i_width[!!plane]);
+ float ref_mean = (float) ref->i_pixel_sum[plane] / (fenc->i_lines[!!plane] * fenc->i_width[!!plane]);
+
+ //early termination
+ if( fabsf( ref_mean - fenc_mean ) < 0.5f && fabsf( 1.f - guess_scale ) < epsilon )
+ {
+ SET_WEIGHT( weights[plane], 0, 1, 0, 0 );
+ continue;
+ }
+
+ if( plane )
+ {
+ weights[plane].i_denom = 6;
+ weights[plane].i_scale = x264_clip3( round( guess_scale * 64 ), 0, 255 );
+ if( weights[plane].i_scale > 127 )
+ {
+ weights[1].weightfn = weights[2].weightfn = NULL;
+ break;
+ }
+ }
+ else
+ x264_weight_get_h264( round( guess_scale * 128 ), 0, &weights[plane] );
+
+ found = 0;
+ mindenom = weights[plane].i_denom;
+ minscale = weights[plane].i_scale;
+ minoff = 0;
+
+ pixel *mcbuf;
+ if( !plane )
+ {
+ if( !fenc->b_intra_calculated )
+ {
+ x264_mb_analysis_t a;
+ x264_lowres_context_init( h, &a );
+ x264_slicetype_frame_cost( h, &a, &fenc, 0, 0, 0, 0 );
+ }
+ mcbuf = x264_weight_cost_init_luma( h, fenc, ref, h->mb.p_weight_buf[0] );
+ origscore = minscore = x264_weight_cost_luma( h, fenc, mcbuf, NULL );
+ }
+ else
+ {
+ pixel *dstu = h->mb.p_weight_buf[0];
+ pixel *dstv = h->mb.p_weight_buf[0]+fenc->i_stride[1]*fenc->i_lines[1];
+ /* Only initialize chroma data once. */
+ if( plane == 1 )
+ x264_weight_cost_init_chroma( h, fenc, ref, dstu, dstv );
+ mcbuf = plane == 1 ? dstu : dstv;
+ origscore = minscore = x264_weight_cost_chroma( h, fenc, mcbuf, NULL );
+ }
+
+ if( !minscore )
+ continue;
+
+ // This gives a slight improvement due to rounding errors but only tests
+ // one offset on lookahead.
+ // TODO: currently searches only offset +1. try other offsets/multipliers/combinations thereof?
+ offset_search = x264_clip3( fenc_mean - ref_mean * minscale / (1 << mindenom) + 0.5f * b_lookahead, -128, 126 );
+ for( int i_off = offset_search; i_off <= offset_search+!b_lookahead; i_off++ )
+ {
+ SET_WEIGHT( weights[plane], 1, minscale, mindenom, i_off );
+ unsigned int s;
+ if( plane )
+ s = x264_weight_cost_chroma( h, fenc, mcbuf, &weights[plane] );
+ else
+ s = x264_weight_cost_luma( h, fenc, mcbuf, &weights[plane] );
+ COPY3_IF_LT( minscore, s, minoff, i_off, found, 1 );
+ }
+ x264_emms();
+
+ /* FIXME: More analysis can be done here on SAD vs. SATD termination. */
+ /* 0.2% termination derived experimentally to avoid weird weights in frames that are mostly intra. */
+ if( !found || (minscale == 1 << mindenom && minoff == 0) || (float)minscore / origscore > 0.998f )
+ {
+ SET_WEIGHT( weights[plane], 0, 1, 0, 0 );
+ continue;
+ }
+ else
+ SET_WEIGHT( weights[plane], 1, minscale, mindenom, minoff );
+
+ if( h->param.analyse.i_weighted_pred == X264_WEIGHTP_FAKE && weights[0].weightfn && !plane )
+ fenc->f_weighted_cost_delta[i_delta_index] = (float)minscore / origscore;
+ }
+
+ //FIXME, what is the correct way to deal with this?
+ if( weights[1].weightfn && weights[2].weightfn && weights[1].i_denom != weights[2].i_denom )
+ {
+ int denom = X264_MIN( weights[1].i_denom, weights[2].i_denom );
+ int i;
+ for( i = 1; i <= 2; i++ )
+ {
+ weights[i].i_scale = x264_clip3( weights[i].i_scale >> ( weights[i].i_denom - denom ), 0, 255 );
+ weights[i].i_denom = denom;
+ h->mc.weight_cache( h, &weights[i] );
+ }
+ }
+
+ if( weights[0].weightfn && b_lookahead )
+ {
+ //scale lowres in lookahead for slicetype_frame_cost
+ pixel *src = ref->buffer_lowres[0];
+ pixel *dst = h->mb.p_weight_buf[0];
+ int width = ref->i_width_lowres + PADH*2;
+ int height = ref->i_lines_lowres + PADV*2;
+ x264_weight_scale_plane( h, dst, ref->i_stride_lowres, src, ref->i_stride_lowres,
+ width, height, &weights[0] );
+ fenc->weighted[0] = h->mb.p_weight_buf[0] + PADH + ref->i_stride_lowres * PADV;
+ }
+}
+
+static void x264_slicetype_mb_cost( x264_t *h, x264_mb_analysis_t *a,
+ x264_frame_t **frames, int p0, int p1, int b,
+ int dist_scale_factor, int do_search[2], const x264_weight_t *w )