lavfi: add xbr filter xBR

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

7 files changed, 767 insertions, 0 deletions

diff --git a/Changelog b/Changelog
index 2cd73ebf7d..a7160e3780 100644
--- a/Changelog
+++ b/Changelog
@@ -10,6 +10,7 @@ version <next>:
 - libutvideo YUV 4:2:2 10bit support
 - XCB-based screen-grabber
 - UDP-Lite support (RFC 3828)
+- xBR scaler
 
 version 2.4:
 - Icecast protocol
diff --git a/LICENSE.md b/LICENSE.md
index e0a431bd2b..dd39b9037c 100644
--- a/LICENSE.md
+++ b/LICENSE.md
@@ -49,6 +49,7 @@ Specifically, the GPL parts of FFmpeg are:
     - vf_stereo3d.c
     - vf_super2xsai.c
     - vf_tinterlace.c
+    - vf_xbr.c
     - vsrc_mptestsrc.c
 
 Should you, for whatever reason, prefer to use version 3 of the (L)GPL, then
diff --git a/configure b/configure
index 978ef1203e..a2d872b68d 100755
--- a/configure
+++ b/configure
@@ -2608,6 +2608,7 @@ vidstabtransform_filter_deps="libvidstab"
 pixfmts_super2xsai_test_deps="super2xsai_filter"
 tinterlace_merge_test_deps="tinterlace_filter"
 tinterlace_pad_test_deps="tinterlace_filter"
+xbr_filter_deps="gpl"
 zmq_filter_deps="libzmq"
 zoompan_filter_deps="swscale"
 
diff --git a/doc/filters.texi b/doc/filters.texi
index be4d9c25e1..5077d5c13f 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -9196,6 +9196,10 @@ Only deinterlace frames marked as interlaced.
 Default value is @samp{all}.
 @end table
 
+@section xbr
+Apply high-quality magnification filter which is designed for pixel art. It follows a set
+of edge-detection rules, see @url{http://www.libretro.com/forums/viewtopic.php?f=6&t=134}.
+
 @anchor{yadif}
 @section yadif
 
diff --git a/libavfilter/Makefile b/libavfilter/Makefile
index 6d868e7973..2c56e383c2 100644
--- a/libavfilter/Makefile
+++ b/libavfilter/Makefile
@@ -198,6 +198,7 @@ OBJS-$(CONFIG_VIDSTABDETECT_FILTER)          += vidstabutils.o vf_vidstabdetect.
 OBJS-$(CONFIG_VIDSTABTRANSFORM_FILTER)       += vidstabutils.o vf_vidstabtransform.o
 OBJS-$(CONFIG_VIGNETTE_FILTER)               += vf_vignette.o
 OBJS-$(CONFIG_W3FDIF_FILTER)                 += vf_w3fdif.o
+OBJS-$(CONFIG_XBR_FILTER)                    += vf_xbr.o
 OBJS-$(CONFIG_YADIF_FILTER)                  += vf_yadif.o
 OBJS-$(CONFIG_ZMQ_FILTER)                    += f_zmq.o
 OBJS-$(CONFIG_ZOOMPAN_FILTER)                += vf_zoompan.o
diff --git a/libavfilter/allfilters.c b/libavfilter/allfilters.c
index d88a9ad25c..2352d44bf9 100644
--- a/libavfilter/allfilters.c
+++ b/libavfilter/allfilters.c
@@ -213,6 +213,7 @@ void avfilter_register_all(void)
     REGISTER_FILTER(VIDSTABTRANSFORM, vidstabtransform, vf);
     REGISTER_FILTER(VIGNETTE,       vignette,       vf);
     REGISTER_FILTER(W3FDIF,         w3fdif,         vf);
+    REGISTER_FILTER(XBR,            xbr,            vf);
     REGISTER_FILTER(YADIF,          yadif,          vf);
     REGISTER_FILTER(ZMQ,            zmq,            vf);
     REGISTER_FILTER(ZOOMPAN,        zoompan,        vf);
diff --git a/libavfilter/vf_xbr.c b/libavfilter/vf_xbr.c
new file mode 100644
index 0000000000..d4ad75b624
--- /dev/null
+++ b/libavfilter/vf_xbr.c
@@ -0,0 +1,758 @@
+/*
+ * This file is part of FFmpeg.
+ *
+ * Copyright (C) 2011, 2012 Hyllian/Jararaca - sergiogdb@gmail.com
+ *
+ * Copyright (c) 2014 Arwa Arif <arwaarif1994@gmail.com>
+ *
+ * FFmpeg is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with FFmpeg; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+/**
+ * @file
+ * XBR Filter is used for depixelization of image.
+ * This is based on Hyllian's 2xBR shader.
+ *
+ * @see : http://www.libretro.com/forums/viewtopic.php?f=6&t=134
+ * @see : https://github.com/yoyofr/iFBA/blob/master/fba_src/src/intf/video/scalers/xbr.cpp
+ * Future work : To implement x3 and x4 scale, and threading.
+ */
+
+#include "libavutil/opt.h"
+#include "libavutil/avassert.h"
+#include "libavutil/pixdesc.h"
+#include "internal.h"
+
+#define RGB_MASK      0x00FFFFFF
+#define LB_MASK       0x00FEFEFE
+#define RED_BLUE_MASK 0x00FF00FF
+#define GREEN_MASK    0x0000FF00
+
+typedef struct {
+    const AVClass *class;
+    int n;
+    uint32_t rgbtoyuv[1<<24];
+} xBRContext;
+
+#define OFFSET(x) offsetof(xBRContext, x)
+static const AVOption xbr_options[] = {
+    { "n", "set scale factor", OFFSET(n), AV_OPT_TYPE_INT, {.i64 = 3}, 2, 4, },
+    { NULL }
+};
+
+AVFILTER_DEFINE_CLASS(xbr);
+
+static uint32_t df(uint32_t x, uint32_t y, const uint32_t *r2y)
+{
+#define YMASK 0xff0000
+#define UMASK 0x00ff00
+#define VMASK 0x0000ff
+
+    uint32_t yuv1 = r2y[x & 0xffffff];
+    uint32_t yuv2 = r2y[y & 0xffffff];
+
+    return (abs((yuv1 & YMASK) - (yuv2 & YMASK)) >> 16) +
+           (abs((yuv1 & UMASK) - (yuv2 & UMASK)) >>  8) +
+           abs((yuv1 & VMASK) - (yuv2 & VMASK));
+}
+
+#define ALPHA_BLEND_128_W(dst, src) dst = ((src & LB_MASK) >> 1) + ((dst & LB_MASK) >> 1)
+
+#define ALPHA_BLEND_32_W(dst, src) \
+    dst = ((RED_BLUE_MASK & ((dst & RED_BLUE_MASK) + ((((src & RED_BLUE_MASK) - \
+          (dst & RED_BLUE_MASK))) >>3))) | (GREEN_MASK & ((dst & GREEN_MASK) + \
+          ((((src & GREEN_MASK) - (dst & GREEN_MASK))) >>3))))
+
+#define ALPHA_BLEND_64_W(dst, src) \
+    dst = ((RED_BLUE_MASK & ((dst & RED_BLUE_MASK) + ((((src & RED_BLUE_MASK) - \
+          (dst & RED_BLUE_MASK))) >>2))) | (GREEN_MASK & ((dst & GREEN_MASK) + \
+          ((((src & GREEN_MASK) - (dst & GREEN_MASK))) >>2))))
+
+#define ALPHA_BLEND_192_W(dst, src) \
+    dst = ((RED_BLUE_MASK & ((dst & RED_BLUE_MASK) + ((((src & RED_BLUE_MASK) - \
+          (dst & RED_BLUE_MASK)) * 3) >>2))) | (GREEN_MASK & ((dst & GREEN_MASK) + \
+          ((((src & GREEN_MASK) - (dst & GREEN_MASK)) * 3) >>2))))
+
+#define ALPHA_BLEND_224_W(dst, src) \
+    dst = ((RED_BLUE_MASK & ((dst & RED_BLUE_MASK) + ((((src & RED_BLUE_MASK) - \
+          (dst & RED_BLUE_MASK)) * 7) >>3))) | (GREEN_MASK & ((dst & GREEN_MASK) + \
+          ((((src & GREEN_MASK) - (dst & GREEN_MASK)) * 7) >>3))))
+
+#define LEFT_UP_2_2X(N3, N2, N1, PIXEL)\
+    ALPHA_BLEND_224_W(E[N3], PIXEL); \
+    ALPHA_BLEND_64_W( E[N2], PIXEL); \
+    E[N1] = E[N2]; \
+
+#define LEFT_2_2X(N3, N2, PIXEL)\
+    ALPHA_BLEND_192_W(E[N3], PIXEL); \
+    ALPHA_BLEND_64_W( E[N2], PIXEL); \
+
+#define UP_2_2X(N3, N1, PIXEL)\
+    ALPHA_BLEND_192_W(E[N3], PIXEL); \
+    ALPHA_BLEND_64_W( E[N1], PIXEL); \
+
+#define DIA_2X(N3, PIXEL)\
+    ALPHA_BLEND_128_W(E[N3], PIXEL); \
+
+#define eq(A, B, r2y)\
+    (df(A, B, r2y) < 155)\
+
+#define FILTRO(PE, PI, PH, PF, PG, PC, PD, PB, PA, G5, C4, G0, D0, C1, B1, F4, I4, H5, I5, A0, A1, N0, N1, N2, N3,r2y) \
+     ex   = (PE!=PH && PE!=PF); \
+     if ( ex )\
+     {\
+          e = (df(PE,PC,r2y)+df(PE,PG,r2y)+df(PI,H5,r2y)+df(PI,F4,r2y))+(df(PH,PF,r2y)<<2); \
+          i = (df(PH,PD,r2y)+df(PH,I5,r2y)+df(PF,I4,r2y)+df(PF,PB,r2y))+(df(PE,PI,r2y)<<2); \
+          if ((e<i)  && ( !eq(PF,PB,r2y) && !eq(PH,PD,r2y) || eq(PE,PI,r2y) && (!eq(PF,I4,r2y) && !eq(PH,I5,r2y)) || eq(PE,PG,r2y) || eq(PE,PC,r2y)) )\
+          {\
+              ke=df(PF,PG,r2y); ki=df(PH,PC,r2y); \
+              ex2 = (PE!=PC && PB!=PC); ex3 = (PE!=PG && PD!=PG); px = (df(PE,PF,r2y) <= df(PE,PH,r2y)) ? PF : PH; \
+              if ( ((ke<<1)<=ki) && ex3 && (ke>=(ki<<1)) && ex2 ) \
+              {\
+                     LEFT_UP_2_2X(N3, N2, N1, px)\
+              }\
+              else if ( ((ke<<1)<=ki) && ex3 ) \
+              {\
+                     LEFT_2_2X(N3, N2, px);\
+              }\
+              else if ( (ke>=(ki<<1)) && ex2 ) \
+              {\
+                     UP_2_2X(N3, N1, px);\
+              }\
+              else \
+              {\
+                     DIA_2X(N3, px);\
+              }\
+          }\
+          else if (e<=i)\
+          {\
+               ALPHA_BLEND_128_W( E[N3], ((df(PE,PF,r2y) <= df(PE,PH,r2y)) ? PF : PH)); \
+          }\
+     }\
+
+static void xbr2x(AVFrame * input, AVFrame * output, const uint32_t * r2y)
+{
+    unsigned int e, i,px;
+    unsigned int ex, ex2, ex3;
+    unsigned int ke, ki;
+    int x,y;
+
+    int next_line = output->linesize[0]>>2;
+
+    for (y = 0; y < input->height; y++) {
+
+        uint32_t pprev;
+        uint32_t pprev2;
+
+        uint32_t * E = (uint32_t *)(output->data[0] + y * output->linesize[0] * 2);
+
+        /* middle. Offset of -8 is given */
+        uint32_t * sa2 = (uint32_t *)(input->data[0] + y * input->linesize[0] - 8);
+        /* up one */
+        uint32_t * sa1 = sa2 - (input->linesize[0]>>2);
+        /* up two */
+        uint32_t * sa0 = sa1 - (input->linesize[0]>>2);
+        /* down one */
+        uint32_t * sa3 = sa2 + (input->linesize[0]>>2);
+        /* down two */
+        uint32_t * sa4 = sa3 + (input->linesize[0]>>2);
+
+        if (y <= 1) {
+            sa0 = sa1;
+            if (y == 0) {
+                sa0 = sa1 = sa2;
+            }
+        }
+
+        if (y >= input->height - 2) {
+            sa4 = sa3;
+            if (y == input->height - 1) {
+                sa4 = sa3 = sa2;
+            }
+        }
+
+        pprev = pprev2 = 2;
+
+        for (x = 0; x < input->width; x++) {
+            uint32_t B1 = sa0[2];
+            uint32_t PB = sa1[2];
+            uint32_t PE = sa2[2];
+            uint32_t PH = sa3[2];
+            uint32_t H5 = sa4[2];
+
+            uint32_t A1 = sa0[pprev];
+            uint32_t PA = sa1[pprev];
+            uint32_t PD = sa2[pprev];
+            uint32_t PG = sa3[pprev];
+            uint32_t G5 = sa4[pprev];
+
+            uint32_t A0 = sa1[pprev2];
+            uint32_t D0 = sa2[pprev2];
+            uint32_t G0 = sa3[pprev2];
+
+            uint32_t C1 = 0;
+            uint32_t PC = 0;
+            uint32_t PF = 0;
+            uint32_t PI = 0;
+            uint32_t I5 = 0;
+
+            uint32_t C4 = 0;
+            uint32_t F4 = 0;
+            uint32_t I4 = 0;
+
+            if (x >= input->width - 2) {
+                if (x == input->width - 1) {
+                    C1 = sa0[2];
+                    PC = sa1[2];
+                    PF = sa2[2];
+                    PI = sa3[2];
+                    I5 = sa4[2];
+
+                    C4 = sa1[2];
+                    F4 = sa2[2];
+                    I4 = sa3[2];
+                } else {
+                    C1 = sa0[3];
+                    PC = sa1[3];
+                    PF = sa2[3];
+                    PI = sa3[3];
+                    I5 = sa4[3];
+
+                    C4 = sa1[3];
+                    F4 = sa2[3];
+                    I4 = sa3[3];
+                }
+            } else {
+                C1 = sa0[3];
+                PC = sa1[3];
+                PF = sa2[3];
+                PI = sa3[3];
+                I5 = sa4[3];
+
+                C4 = sa1[4];
+                F4 = sa2[4];
+                I4 = sa3[4];
+            }
+
+            E[0] = E[1] = E[next_line] = E[next_line + 1] = PE; // 0, 1, 2, 3
+
+            FILTRO(PE, PI, PH, PF, PG, PC, PD, PB, PA, G5, C4, G0, D0, C1, B1, F4, I4, H5, I5, A0, A1, 0, 1, next_line, next_line+1,r2y);
+            FILTRO(PE, PC, PF, PB, PI, PA, PH, PD, PG, I4, A1, I5, H5, A0, D0, B1, C1, F4, C4, G5, G0, next_line, 0, next_line+1, 1,r2y);
+            FILTRO(PE, PA, PB, PD, PC, PG, PF, PH, PI, C1, G0, C4, F4, G5, H5, D0, A0, B1, A1, I4, I5, next_line+1, next_line, 1, 0,r2y);
+            FILTRO(PE, PG, PD, PH, PA, PI, PB, PF, PC, A0, I5, A1, B1, I4, F4, H5, G5, D0, G0, C1, C4, 1, next_line+1, 0, next_line,r2y);
+
+            sa0 += 1;
+            sa1 += 1;
+            sa2 += 1;
+            sa3 += 1;
+            sa4 += 1;
+
+            E += 2;
+
+            if (pprev2){
+                pprev2--;
+                pprev = 1;
+            }
+        }
+    }
+}
+#undef FILTRO
+
+#define LEFT_UP_2_3X(N7, N5, N6, N2, N8, PIXEL)\
+    ALPHA_BLEND_192_W(E[N7], PIXEL); \
+    ALPHA_BLEND_64_W( E[N6], PIXEL); \
+    E[N5] = E[N7]; \
+    E[N2] = E[N6]; \
+    E[N8] =  PIXEL;\
+
+#define LEFT_2_3X(N7, N5, N6, N8, PIXEL)\
+    ALPHA_BLEND_192_W(E[N7], PIXEL); \
+    ALPHA_BLEND_64_W( E[N5], PIXEL); \
+    ALPHA_BLEND_64_W( E[N6], PIXEL); \
+    E[N8] =  PIXEL;\
+
+#define UP_2_3X(N5, N7, N2, N8, PIXEL)\
+    ALPHA_BLEND_192_W(E[N5], PIXEL); \
+    ALPHA_BLEND_64_W( E[N7], PIXEL); \
+    ALPHA_BLEND_64_W( E[N2], PIXEL); \
+    E[N8] =  PIXEL;\
+
+#define DIA_3X(N8, N5, N7, PIXEL)\
+    ALPHA_BLEND_224_W(E[N8], PIXEL); \
+    ALPHA_BLEND_32_W(E[N5], PIXEL); \
+    ALPHA_BLEND_32_W(E[N7], PIXEL); \
+
+#define FILTRO(PE, PI, PH, PF, PG, PC, PD, PB, PA, G5, C4, G0, D0, C1, B1, F4, I4, H5, I5, A0, A1, N0, N1, N2, N3, N4, N5, N6, N7, N8,r2y) \
+     ex   = (PE!=PH && PE!=PF); \
+     if ( ex )\
+     {\
+          e = (df(PE,PC,r2y)+df(PE,PG,r2y)+df(PI,H5,r2y)+df(PI,F4,r2y))+(df(PH,PF,r2y)<<2); \
+          i = (df(PH,PD,r2y)+df(PH,I5,r2y)+df(PF,I4,r2y)+df(PF,PB,r2y))+(df(PE,PI,r2y)<<2); \
+          if ((e<i)  && ( !eq(PF,PB,r2y) && !eq(PF,PC,r2y) || !eq(PH,PD,r2y) && !eq(PH,PG,r2y) || eq(PE,PI,r2y) && (!eq(PF,F4,r2y) && !eq(PF,I4,r2y) || !eq(PH,H5,r2y) && !eq(PH,I5,r2y)) || eq(PE,PG,r2y) || eq(PE,PC,r2y)) )\
+          {\
+              ke=df(PF,PG,r2y); ki=df(PH,PC,r2y); \
+              ex2 = (PE!=PC && PB!=PC); ex3 = (PE!=PG && PD!=PG); px = (df(PE,PF,r2y) <= df(PE,PH,r2y)) ? PF : PH; \
+              if ( ((ke<<1)<=ki) && ex3 && (ke>=(ki<<1)) && ex2 ) \
+              {\
+                     LEFT_UP_2_3X(N7, N5, N6, N2, N8, px)\
+              }\
+              else if ( ((ke<<1)<=ki) && ex3 ) \
+              {\
+                     LEFT_2_3X(N7, N5, N6, N8, px);\
+              }\
+              else if ( (ke>=(ki<<1)) && ex2 ) \
+              {\
+                     UP_2_3X(N5, N7, N2, N8, px);\
+              }\
+              else \
+              {\
+                     DIA_3X(N8, N5, N7, px);\
+              }\
+          }\
+          else if (e<=i)\
+          {\
+               ALPHA_BLEND_128_W( E[N8], ((df(PE,PF,r2y) <= df(PE,PH,r2y)) ? PF : PH)); \
+          }\
+     }\
+
+static void xbr3x(AVFrame * input, AVFrame * output, const uint32_t * r2y)
+{
+    const int nl = output->linesize[0]>>2;
+    const int nl1 = nl + nl;
+
+    unsigned int e, i,px;
+    unsigned int ex, ex2, ex3;
+    unsigned int ke, ki;
+
+    uint32_t pprev;
+    uint32_t pprev2;
+
+    int x,y;
+
+    for (y = 0; y < input->height; y++) {
+
+        uint32_t * E = (uint32_t *)(output->data[0] + y * output->linesize[0] * 3);
+
+        /* middle. Offset of -8 is given */
+        uint32_t * sa2 = (uint32_t *)(input->data[0] + y * input->linesize[0] - 8);
+        /* up one */
+        uint32_t * sa1 = sa2 - (input->linesize[0]>>2);
+        /* up two */
+        uint32_t * sa0 = sa1 - (input->linesize[0]>>2);
+        /* down one */
+        uint32_t * sa3 = sa2 + (input->linesize[0]>>2);
+        /* down two */
+        uint32_t * sa4 = sa3 + (input->linesize[0]>>2);
+
+        if (y <= 1){
+            sa0 = sa1;
+            if (y == 0){
+                sa0 = sa1 = sa2;
+            }
+        }
+
+        if (y >= input->height - 2){
+            sa4 = sa3;
+            if (y == input->height - 1){
+                sa4 = sa3 = sa2;
+            }
+        }
+
+        pprev = pprev2 = 2;
+
+        for (x = 0; x < input->width; x++){
+            uint32_t B1 = sa0[2];
+            uint32_t PB = sa1[2];
+            uint32_t PE = sa2[2];
+            uint32_t PH = sa3[2];
+            uint32_t H5 = sa4[2];
+
+            uint32_t A1 = sa0[pprev];
+            uint32_t PA = sa1[pprev];
+            uint32_t PD = sa2[pprev];
+            uint32_t PG = sa3[pprev];
+            uint32_t G5 = sa4[pprev];
+
+            uint32_t A0 = sa1[pprev2];
+            uint32_t D0 = sa2[pprev2];
+            uint32_t G0 = sa3[pprev2];
+
+            uint32_t C1 = 0;
+            uint32_t PC = 0;
+            uint32_t PF = 0;
+            uint32_t PI = 0;
+            uint32_t I5 = 0;
+
+            uint32_t C4 = 0;
+            uint32_t F4 = 0;
+            uint32_t I4 = 0;
+
+            if (x >= input->width - 2){
+                if (x == input->width - 1){
+                    C1 = sa0[2];
+                    PC = sa1[2];
+                    PF = sa2[2];
+                    PI = sa3[2];
+                    I5 = sa4[2];
+
+                    C4 = sa1[2];
+                    F4 = sa2[2];
+                    I4 = sa3[2];
+                } else {
+                    C1 = sa0[3];
+                    PC = sa1[3];
+                    PF = sa2[3];
+                    PI = sa3[3];
+                    I5 = sa4[3];
+
+                    C4 = sa1[3];
+                    F4 = sa2[3];
+                    I4 = sa3[3];
+                }
+            } else {
+                C1 = sa0[3];
+                PC = sa1[3];
+                PF = sa2[3];
+                PI = sa3[3];
+                I5 = sa4[3];
+
+                C4 = sa1[4];
+                F4 = sa2[4];
+                I4 = sa3[4];
+            }
+
+            E[0]   = E[1]     = E[2]     = PE;
+            E[nl]  = E[nl+1]  = E[nl+2]  = PE; // 3, 4, 5
+            E[nl1] = E[nl1+1] = E[nl1+2] = PE; // 6, 7, 8
+
+            FILTRO(PE, PI, PH, PF, PG, PC, PD, PB, PA, G5, C4, G0, D0, C1, B1, F4, I4, H5, I5, A0, A1, 0, 1, 2, nl, nl+1, nl+2, nl1, nl1+1, nl1+2,r2y);
+            FILTRO(PE, PC, PF, PB, PI, PA, PH, PD, PG, I4, A1, I5, H5, A0, D0, B1, C1, F4, C4, G5, G0, nl1, nl, 0, nl1+1, nl+1, 1, nl1+2, nl+2, 2,r2y);
+            FILTRO(PE, PA, PB, PD, PC, PG, PF, PH, PI, C1, G0, C4, F4, G5, H5, D0, A0, B1, A1, I4, I5, nl1+2, nl1+1, nl1, nl+2, nl+1, nl, 2, 1, 0,r2y);
+            FILTRO(PE, PG, PD, PH, PA, PI, PB, PF, PC, A0, I5, A1, B1, I4, F4, H5, G5, D0, G0, C1, C4, 2, nl+2, nl1+2, 1, nl+1, nl1+1, 0, nl, nl1,r2y);
+
+            sa0 += 1;
+            sa1 += 1;
+            sa2 += 1;
+            sa3 += 1;
+            sa4 += 1;
+
+            E += 3;
+
+            if (pprev2){
+                pprev2--;
+                pprev = 1;
+            }
+        }
+    }
+}
+#undef FILTRO
+
+#define LEFT_UP_2(N15, N14, N11, N13, N12, N10, N7, N3, PIXEL)\
+    ALPHA_BLEND_192_W(E[N13], PIXEL); \
+    ALPHA_BLEND_64_W( E[N12], PIXEL); \
+    E[N15] = E[N14] = E[N11] = PIXEL; \
+    E[N10] = E[N3] = E[N12]; \
+    E[N7]  = E[N13]; \
+
+#define LEFT_2(N15, N14, N11, N13, N12, N10, PIXEL)\
+    ALPHA_BLEND_192_W(E[N11], PIXEL); \
+    ALPHA_BLEND_192_W(E[N13], PIXEL); \
+    ALPHA_BLEND_64_W( E[N10], PIXEL); \
+    ALPHA_BLEND_64_W( E[N12], PIXEL); \
+    E[N14] = PIXEL; \
+    E[N15] = PIXEL; \
+
+#define UP_2(N15, N14, N11, N3, N7, N10, PIXEL)\
+    ALPHA_BLEND_192_W(E[N14], PIXEL); \
+    ALPHA_BLEND_192_W(E[N7 ], PIXEL); \
+    ALPHA_BLEND_64_W( E[N10], PIXEL); \
+    ALPHA_BLEND_64_W( E[N3 ], PIXEL); \
+    E[N11] = PIXEL; \
+    E[N15] = PIXEL; \
+
+#define DIA(N15, N14, N11, PIXEL)\
+    ALPHA_BLEND_128_W(E[N11], PIXEL); \
+    ALPHA_BLEND_128_W(E[N14], PIXEL); \
+    E[N15] = PIXEL; \
+
+#define FILTRO(PE, PI, PH, PF, PG, PC, PD, PB, PA, G5, C4, G0, D0, C1, B1, F4, I4, H5, I5, A0, A1, N15, N14, N11, N3, N7, N10, N13, N12, N9, N6, N2, N1, N5, N8, N4, N0,r2y) \
+     ex   = (PE!=PH && PE!=PF); \
+     if ( ex )\
+     {\
+          e = (df(PE,PC,r2y)+df(PE,PG,r2y)+df(PI,H5,r2y)+df(PI,F4,r2y))+(df(PH,PF,r2y)<<2); \
+          i = (df(PH,PD,r2y)+df(PH,I5,r2y)+df(PF,I4,r2y)+df(PF,PB,r2y))+(df(PE,PI,r2y)<<2); \
+          if ((e<i)  && ( !eq(PF,PB,r2y) && !eq(PH,PD,r2y) || eq(PE,PI,r2y) && (!eq(PF,I4,r2y) && !eq(PH,I5,r2y)) || eq(PE,PG,r2y) || eq(PE,PC,r2y)) )\
+          {\
+              ke=df(PF,PG,r2y); ki=df(PH,PC,r2y); \
+              ex2 = (PE!=PC && PB!=PC); ex3 = (PE!=PG && PD!=PG); px = (df(PE,PF,r2y) <= df(PE,PH,r2y)) ? PF : PH; \
+              if ( ((ke<<1)<=ki) && ex3 && (ke>=(ki<<1)) && ex2 ) \
+              {\
+                     LEFT_UP_2(N15, N14, N11, N13, N12, N10, N7, N3, px)\
+              }\
+              else if ( ((ke<<1)<=ki) && ex3 ) \
+              {\
+                     LEFT_2(N15, N14, N11, N13, N12, N10, px)\
+              }\
+              else if ( (ke>=(ki<<1)) && ex2 ) \
+              {\
+                     UP_2(N15, N14, N11, N3, N7, N10, px)\
+              }\
+              else \
+              {\
+                     DIA(N15, N14, N11, px)\
+              }\
+          }\
+          else if (e<=i)\
+          {\
+               ALPHA_BLEND_128_W( E[N15], ((df(PE,PF,r2y) <= df(PE,PH,r2y)) ? PF : PH)); \
+          }\
+     }\
+
+static void xbr4x(AVFrame * input, AVFrame * output, const uint32_t * r2y)
+{
+
+    const int nl = output->linesize[0]>>2;
+    const int nl1 = nl + nl;
+    const int nl2 = nl1 + nl;
+
+    unsigned int e, i, px;
+    unsigned int ex, ex2, ex3;
+    unsigned int ke, ki;
+
+    uint32_t pprev;
+    uint32_t pprev2;
+
+    int x,y;
+
+    for (y = 0; y < input->height; y++){
+
+        uint32_t * E = (uint32_t *)(output->data[0] + y * output->linesize[0] * 4);
+
+        /* middle. Offset of -8 is given */
+        uint32_t * sa2 = (uint32_t *)(input->data[0] + y * input->linesize[0] - 8);
+        /* up one */
+        uint32_t * sa1 = sa2 - (input->linesize[0]>>2);
+        /* up two */
+        uint32_t * sa0 = sa1 - (input->linesize[0]>>2);
+        /* down one */
+        uint32_t * sa3 = sa2 + (input->linesize[0]>>2);
+        /* down two */
+        uint32_t * sa4 = sa3 + (input->linesize[0]>>2);
+
+        if (y <= 1){
+            sa0 = sa1;
+            if (y == 0){
+                sa0 = sa1 = sa2;
+            }
+        }
+
+        if (y >= input->height - 2){
+            sa4 = sa3;
+            if (y == input->height - 1){
+                sa4 = sa3 = sa2;
+            }
+        }
+
+        pprev = pprev2 = 2;
+
+        for (x = 0; x < input->width; x++){
+            uint32_t B1 = sa0[2];
+            uint32_t PB = sa1[2];
+            uint32_t PE = sa2[2];
+            uint32_t PH = sa3[2];
+            uint32_t H5 = sa4[2];
+
+            uint32_t A1 = sa0[pprev];
+            uint32_t PA = sa1[pprev];
+            uint32_t PD = sa2[pprev];
+            uint32_t PG = sa3[pprev];
+            uint32_t G5 = sa4[pprev];
+
+            uint32_t A0 = sa1[pprev2];
+            uint32_t D0 = sa2[pprev2];
+            uint32_t G0 = sa3[pprev2];
+
+            uint32_t C1 = 0;
+            uint32_t PC = 0;
+            uint32_t PF = 0;
+            uint32_t PI = 0;
+            uint32_t I5 = 0;
+
+            uint32_t C4 = 0;
+            uint32_t F4 = 0;
+            uint32_t I4 = 0;
+
+            if (x >= input->width - 2){
+                if (x == input->width - 1){
+                    C1 = sa0[2];
+                    PC = sa1[2];
+                    PF = sa2[2];
+                    PI = sa3[2];
+                    I5 = sa4[2];
+
+                    C4 = sa1[2];
+                    F4 = sa2[2];
+                    I4 = sa3[2];
+                } else {
+                    C1 = sa0[3];
+                    PC = sa1[3];
+                    PF = sa2[3];
+                    PI = sa3[3];
+                    I5 = sa4[3];
+
+                    C4 = sa1[3];
+                    F4 = sa2[3];
+                    I4 = sa3[3];
+                }
+            } else {
+                C1 = sa0[3];
+                PC = sa1[3];
+                PF = sa2[3];
+                PI = sa3[3];
+                I5 = sa4[3];
+
+                C4 = sa1[4];
+                F4 = sa2[4];
+                I4 = sa3[4];
+            }
+
+            E[0]   = E[1]     = E[2]     = E[3]     = PE;
+            E[nl]  = E[nl+1]  = E[nl+2]  = E[nl+3]  = PE; //  4,  5,  6,  7
+            E[nl1] = E[nl1+1] = E[nl1+2] = E[nl1+3] = PE; //  8,  9, 10, 11
+            E[nl2] = E[nl2+1] = E[nl2+2] = E[nl2+3] = PE; // 12, 13, 14, 15
+
+            FILTRO(PE, PI, PH, PF, PG, PC, PD, PB, PA, G5, C4, G0, D0, C1, B1, F4, I4, H5, I5, A0, A1, nl2+3, nl2+2, nl1+3,  3,  nl+3, nl1+2, nl2+1, nl2,  nl1+1,  nl+2, 2,  1, nl+1, nl1, nl, 0,r2y);
+            FILTRO(PE, PC, PF, PB, PI, PA, PH, PD, PG, I4, A1, I5, H5, A0, D0, B1, C1, F4, C4, G5, G0,  3,  nl+3,  2,  0,  1,  nl+2, nl1+3, nl2+3, nl1+2,  nl+1, nl,  nl1, nl1+1,nl2+2,nl2+1,nl2,r2y);
+            FILTRO(PE, PA, PB, PD, PC, PG, PF, PH, PI, C1, G0, C4, F4, G5, H5, D0, A0, B1, A1, I4, I5,  0,  1,  nl, nl2,  nl1,  nl+1,  2,  3,  nl+2,  nl1+1, nl2+1,nl2+2,nl1+2, nl+3,nl1+3,nl2+3,r2y);
+            FILTRO(PE, PG, PD, PH, PA, PI, PB, PF, PC, A0, I5, A1, B1, I4, F4, H5, G5, D0, G0, C1, C4, nl2,  nl1, nl2+1, nl2+3, nl2+2,  nl1+1,  nl,  0,  nl+1, nl1+2, nl1+3, nl+3, nl+2, 1, 2, 3,r2y);
+
+            sa0 += 1;
+            sa1 += 1;
+            sa2 += 1;
+            sa3 += 1;
+            sa4 += 1;
+
+            E += 4;
+
+            if (pprev2){
+                pprev2--;
+                pprev = 1;
+            }
+        }
+    }
+}
+#undef FILTRO
+
+static int config_output(AVFilterLink *outlink)
+{
+    AVFilterContext *ctx = outlink->src;
+    xBRContext *xbr = ctx->priv;
+    AVFilterLink *inlink = ctx->inputs[0];
+
+    outlink->w = inlink->w * xbr->n;
+    outlink->h = inlink->h * xbr->n;
+    return 0;
+}
+
+static int query_formats(AVFilterContext *ctx)
+{
+    static const enum AVPixelFormat pix_fmts[] = {
+        AV_PIX_FMT_0RGB32, AV_PIX_FMT_NONE,
+    };
+
+    ff_set_common_formats(ctx, ff_make_format_list(pix_fmts));
+    return 0;
+}
+
+static int filter_frame(AVFilterLink *inlink, AVFrame *in)
+{
+    AVFilterContext *ctx = inlink->dst;
+    AVFilterLink *outlink = ctx->outputs[0];
+    xBRContext *xbr = ctx->priv;
+    const uint32_t *r2y = xbr->rgbtoyuv;
+
+    AVFrame *out = ff_get_video_buffer(outlink, outlink->w, outlink->h);
+    if (!out) {
+        av_frame_free(&in);
+        return AVERROR(ENOMEM);
+    }
+
+    av_frame_copy_props(out, in);
+    if(xbr->n == 4)
+        xbr4x(in,out,r2y);
+    else if(xbr->n == 3)
+        xbr3x(in,out,r2y);
+    else
+        xbr2x(in,out,r2y);
+
+    out->width  = outlink->w;
+    out->height = outlink->h;
+
+    av_frame_free(&in);
+    return ff_filter_frame(outlink, out);
+}
+
+static int init(AVFilterContext *ctx)
+{
+    xBRContext *xbr = ctx->priv;
+    uint32_t c;
+    int bg, rg, g;
+
+    for (bg=-255; bg<256; bg++) {
+        for (rg=-255; rg<256; rg++) {
+            const uint32_t u = (uint32_t)((-169*rg + 500*bg)/1000) + 128;
+            const uint32_t v = (uint32_t)(( 500*rg -  81*bg)/1000) + 128;
+            int startg = FFMAX3(-bg, -rg, 0);
+            int endg = FFMIN3(255-bg, 255-rg, 255);
+            uint32_t y = (uint32_t)(( 299*rg + 1000*startg + 114*bg)/1000);
+            c = bg + (rg<<16) + 0x010101 * startg;
+            for (g = startg; g <= endg; g++) {
+                xbr->rgbtoyuv[c] = ((y++) << 16) + (u << 8) + v;
+                c+= 0x010101;
+            }
+        }
+    }
+
+    return 0;
+}
+
+static const AVFilterPad xbr_inputs[] = {
+    {
+        .name         = "default",
+        .type         = AVMEDIA_TYPE_VIDEO,
+        .filter_frame = filter_frame,
+    },
+    { NULL }
+};
+
+static const AVFilterPad xbr_outputs[] = {
+    {
+        .name         = "default",
+        .type         = AVMEDIA_TYPE_VIDEO,
+        .config_props = config_output,
+    },
+    { NULL }
+};
+
+AVFilter ff_vf_xbr = {
+    .name          = "xbr",
+    .description   = NULL_IF_CONFIG_SMALL("Scale the input by 2 using xbr algorithm."),
+    .inputs        = xbr_inputs,
+    .outputs       = xbr_outputs,
+    .query_formats = query_formats,
+    .priv_size     = sizeof(xBRContext),
+    .priv_class    = &xbr_class,
+    .init          = init,
+};