@@ -22,6 +22,7 @@ version <next>:

 - RF64 support in WAV muxer

 - noise filter ported from libmpcodecs

 - Subtitles character encoding conversion

+- blend filter

 version 1.1:

@@ -1778,6 +1778,114 @@ threshold, and defaults to 98.

 @var{threshold} is the threshold below which a pixel value is

 considered black, and defaults to 32.

+@section blend

+

+Blend two video frames into each other.

+

+It takes two input streams and outputs one stream, the first input is the

+"top" layer and second input is "bottom" layer.

+Output terminates when shortest input terminates.

+

+This filter accepts a list of options in the form of @var{key}=@var{value}

+pairs separated by ":". A description of the accepted options follows.

+

+@table @option

+@item c0_mode

+@item c1_mode

+@item c2_mode

+@item c3_mode

+@item all_mode

+Set blend mode for specific pixel component or all pixel components in case

+of @var{all_mode}. Default value is @code{normal}.

+

+Available values for component modes are:

+@table @samp

+@item addition

+@item and

+@item average

+@item burn

+@item darken

+@item difference

+@item divide

+@item dodge

+@item exclusion

+@item hardlight

+@item lighten

+@item multiply

+@item negation

+@item normal

+@item or

+@item overlay

+@item phoenix

+@item pinlight

+@item reflect

+@item screen

+@item softlight

+@item subtract

+@item vividlight

+@item xor

+@end table

+

+@item c0_opacity

+@item c1_opacity

+@item c2_opacity

+@item c3_opacity

+@item all_opacity

+Set blend opacity for specific pixel component or all pixel components in case

+of @var{all_expr}. Only used in combination with pixel component blend modes.

+

+@item c0_expr

+@item c1_expr

+@item c2_expr

+@item c3_expr

+@item all_expr

+Set blend expression for specific pixel component or all pixel components in case

+of @var{all_expr}. Note that related mode options will be ignored if those are set.

+

+The expressions can use the following variables:

+

+@table @option

+@item X

+@item Y

+the coordinates of the current sample

+

+@item W

+@item H

+the width and height of currently filtered plane

+

+@item SW

+@item SH

+Width and height scale depending on the currently filtered plane. It is the

+ratio between the corresponding luma plane number of pixels and the current

+plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and

+@code{0.5,0.5} for chroma planes.

+

+@item T

+Time of the current frame, expressed in seconds.

+

+@item TOP, A

+Value of pixel component at current location for first video frame (top layer).

+

+@item BOTTOM, B

+Value of pixel component at current location for second video frame (bottom layer).

+@end table

+@end table

+

+@itemize

+

+@item

+Apply transition from bottom layer to top layer in first 10 seconds:

+@example

+blend=all_expr='A*(if(gte(T,10),1,T/10))+B*(1-(if(gte(T,10),1,T/10)))'

+@end example

+

+@item

+Apply 1x1 checkerboard effect:

+@example

+blend=all_expr='if(eq(mod(X,2),mod(Y,2)),A,B)'

+@end example

+@end itemize

+

 @section boxblur

 Apply boxblur algorithm to the input video.

@@ -100,6 +100,7 @@ OBJS-$(CONFIG_ALPHAMERGE_FILTER)             += vf_alphamerge.o

 OBJS-$(CONFIG_BBOX_FILTER)                   += bbox.o vf_bbox.o

 OBJS-$(CONFIG_BLACKDETECT_FILTER)            += vf_blackdetect.o

 OBJS-$(CONFIG_BLACKFRAME_FILTER)             += vf_blackframe.o

+OBJS-$(CONFIG_BLEND_FILTER)                  += vf_blend.o

 OBJS-$(CONFIG_BOXBLUR_FILTER)                += vf_boxblur.o

 OBJS-$(CONFIG_COLORMATRIX_FILTER)            += vf_colormatrix.o

 OBJS-$(CONFIG_COPY_FILTER)                   += vf_copy.o

@@ -94,6 +94,7 @@ void avfilter_register_all(void)

     REGISTER_FILTER(BBOX,           bbox,           vf);

     REGISTER_FILTER(BLACKDETECT,    blackdetect,    vf);

     REGISTER_FILTER(BLACKFRAME,     blackframe,     vf);

+    REGISTER_FILTER(BLEND,          blend,          vf);

     REGISTER_FILTER(BOXBLUR,        boxblur,        vf);

     REGISTER_FILTER(COLORMATRIX,    colormatrix,    vf);

     REGISTER_FILTER(COPY,           copy,           vf);

@@ -29,8 +29,8 @@

 #include "libavutil/avutil.h"

 #define LIBAVFILTER_VERSION_MAJOR  3

-#define LIBAVFILTER_VERSION_MINOR  38

-#define LIBAVFILTER_VERSION_MICRO 106

+#define LIBAVFILTER_VERSION_MINOR  39

+#define LIBAVFILTER_VERSION_MICRO 100

 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \

                                                LIBAVFILTER_VERSION_MINOR, \

new file mode 100644

@@ -0,0 +1,474 @@

+/*

+ * Copyright (c) 2013 Paul B Mahol

+ *

+ * This file is part of FFmpeg.

+ *

+ * FFmpeg is free software; you can redistribute it and/or

+ * modify it under the terms of the GNU Lesser General Public

+ * License as published by the Free Software Foundation; either

+ * version 2.1 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

+ * Lesser General Public License for more details.

+ *

+ * You should have received a copy of the GNU Lesser 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

+ */

+

+#include "libavutil/imgutils.h"

+#include "libavutil/eval.h"

+#include "libavutil/opt.h"

+#include "libavutil/pixfmt.h"

+#include "avfilter.h"

+#include "bufferqueue.h"

+#include "formats.h"

+#include "internal.h"

+#include "video.h"

+

+#define TOP    0

+#define BOTTOM 1

+

+enum BlendMode {

+    BLEND_UNSET = -1,

+    BLEND_NORMAL,

+    BLEND_ADDITION,

+    BLEND_AND,

+    BLEND_AVERAGE,

+    BLEND_BURN,

+    BLEND_DARKEN,

+    BLEND_DIFFERENCE,

+    BLEND_DIVIDE,

+    BLEND_DODGE,

+    BLEND_EXCLUSION,

+    BLEND_HARDLIGHT,

+    BLEND_LIGHTEN,

+    BLEND_MULTIPLY,

+    BLEND_NEGATION,

+    BLEND_OR,

+    BLEND_OVERLAY,

+    BLEND_PHOENIX,

+    BLEND_PINLIGHT,

+    BLEND_REFLECT,

+    BLEND_SCREEN,

+    BLEND_SOFTLIGHT,

+    BLEND_SUBTRACT,

+    BLEND_VIVIDLIGHT,

+    BLEND_XOR,

+    BLEND_NB

+};

+

+static const char *const var_names[] = {   "X",   "Y",   "W",   "H",   "SW",   "SH",   "T",     "A",        "B",   "TOP",   "BOTTOM",        NULL };

+enum                                   { VAR_X, VAR_Y, VAR_W, VAR_H, VAR_SW, VAR_SH, VAR_T,   VAR_A,      VAR_B, VAR_TOP, VAR_BOTTOM, VAR_VARS_NB };

+

+typedef struct FilterParams {

+    enum BlendMode mode;

+    double values[VAR_VARS_NB];

+    double opacity;

+    AVExpr *e;

+    char *expr_str;

+    void (*blend)(const uint8_t *top, int top_linesize,

+                  const uint8_t *bottom, int bottom_linesize,

+                  uint8_t *dst, int dst_linesize,

+                  int width, int height, struct FilterParams *param);

+} FilterParams;

+

+typedef struct {

+    const AVClass *class;

+    struct FFBufQueue queue_top;

+    struct FFBufQueue queue_bottom;

+    int hsub, vsub;             ///< chroma subsampling values

+    int frame_requested;

+    char *all_expr;

+    enum BlendMode all_mode;

+    double all_opacity;

+

+    FilterParams params[4];

+} BlendContext;

+

+#define OFFSET(x) offsetof(BlendContext, x)

+#define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM

+

+static const AVOption blend_options[] = {

+    { "c0_mode", "set component #0 blend mode", OFFSET(params[0].mode), AV_OPT_TYPE_INT, {.i64=0}, 0, BLEND_NB-1, FLAGS, "mode"},

+    { "c1_mode", "set component #1 blend mode", OFFSET(params[1].mode), AV_OPT_TYPE_INT, {.i64=0}, 0, BLEND_NB-1, FLAGS, "mode"},

+    { "c2_mode", "set component #2 blend mode", OFFSET(params[2].mode), AV_OPT_TYPE_INT, {.i64=0}, 0, BLEND_NB-1, FLAGS, "mode"},

+    { "c3_mode", "set component #3 blend mode", OFFSET(params[3].mode), AV_OPT_TYPE_INT, {.i64=0}, 0, BLEND_NB-1, FLAGS, "mode"},

+    { "all_mode", "set blend mode for all components", OFFSET(all_mode), AV_OPT_TYPE_INT, {.i64=-1},-1, BLEND_NB-1, FLAGS, "mode"},

+    { "addition",   "", 0, AV_OPT_TYPE_CONST, {.i64=BLEND_ADDITION},   0, 0, FLAGS, "mode" },

+    { "and",        "", 0, AV_OPT_TYPE_CONST, {.i64=BLEND_AND},        0, 0, FLAGS, "mode" },

+    { "average",    "", 0, AV_OPT_TYPE_CONST, {.i64=BLEND_AVERAGE},    0, 0, FLAGS, "mode" },

+    { "burn",       "", 0, AV_OPT_TYPE_CONST, {.i64=BLEND_BURN},       0, 0, FLAGS, "mode" },

+    { "darken",     "", 0, AV_OPT_TYPE_CONST, {.i64=BLEND_DARKEN},     0, 0, FLAGS, "mode" },

+    { "difference", "", 0, AV_OPT_TYPE_CONST, {.i64=BLEND_DIFFERENCE}, 0, 0, FLAGS, "mode" },

+    { "divide",     "", 0, AV_OPT_TYPE_CONST, {.i64=BLEND_DIVIDE},     0, 0, FLAGS, "mode" },

+    { "dodge",      "", 0, AV_OPT_TYPE_CONST, {.i64=BLEND_DODGE},      0, 0, FLAGS, "mode" },

+    { "exclusion",  "", 0, AV_OPT_TYPE_CONST, {.i64=BLEND_EXCLUSION},  0, 0, FLAGS, "mode" },

+    { "hardlight",  "", 0, AV_OPT_TYPE_CONST, {.i64=BLEND_HARDLIGHT},  0, 0, FLAGS, "mode" },

+    { "lighten",    "", 0, AV_OPT_TYPE_CONST, {.i64=BLEND_LIGHTEN},    0, 0, FLAGS, "mode" },

+    { "multiply",   "", 0, AV_OPT_TYPE_CONST, {.i64=BLEND_MULTIPLY},   0, 0, FLAGS, "mode" },

+    { "negation",   "", 0, AV_OPT_TYPE_CONST, {.i64=BLEND_NEGATION},   0, 0, FLAGS, "mode" },

+    { "normal",     "", 0, AV_OPT_TYPE_CONST, {.i64=BLEND_NORMAL},     0, 0, FLAGS, "mode" },

+    { "or",         "", 0, AV_OPT_TYPE_CONST, {.i64=BLEND_OR},         0, 0, FLAGS, "mode" },

+    { "overlay",    "", 0, AV_OPT_TYPE_CONST, {.i64=BLEND_OVERLAY},    0, 0, FLAGS, "mode" },

+    { "phoenix",    "", 0, AV_OPT_TYPE_CONST, {.i64=BLEND_PHOENIX},    0, 0, FLAGS, "mode" },

+    { "pinlight",   "", 0, AV_OPT_TYPE_CONST, {.i64=BLEND_PINLIGHT},   0, 0, FLAGS, "mode" },

+    { "reflect",    "", 0, AV_OPT_TYPE_CONST, {.i64=BLEND_REFLECT},    0, 0, FLAGS, "mode" },

+    { "screen",     "", 0, AV_OPT_TYPE_CONST, {.i64=BLEND_SCREEN},     0, 0, FLAGS, "mode" },

+    { "softlight",  "", 0, AV_OPT_TYPE_CONST, {.i64=BLEND_SOFTLIGHT},  0, 0, FLAGS, "mode" },

+    { "subtract",   "", 0, AV_OPT_TYPE_CONST, {.i64=BLEND_SUBTRACT},   0, 0, FLAGS, "mode" },

+    { "vividlight", "", 0, AV_OPT_TYPE_CONST, {.i64=BLEND_VIVIDLIGHT}, 0, 0, FLAGS, "mode" },

+    { "xor",        "", 0, AV_OPT_TYPE_CONST, {.i64=BLEND_XOR},        0, 0, FLAGS, "mode" },

+    { "c0_expr",  "set color component #0 expression", OFFSET(params[0].expr_str), AV_OPT_TYPE_STRING, {.str=NULL}, CHAR_MIN, CHAR_MAX, FLAGS },

+    { "c1_expr",  "set color component #1 expression", OFFSET(params[1].expr_str), AV_OPT_TYPE_STRING, {.str=NULL}, CHAR_MIN, CHAR_MAX, FLAGS },

+    { "c2_expr",  "set color component #2 expression", OFFSET(params[2].expr_str), AV_OPT_TYPE_STRING, {.str=NULL}, CHAR_MIN, CHAR_MAX, FLAGS },

+    { "c3_expr",  "set color component #3 expression", OFFSET(params[3].expr_str), AV_OPT_TYPE_STRING, {.str=NULL}, CHAR_MIN, CHAR_MAX, FLAGS },

+    { "all_expr", "set expression for all color components", OFFSET(all_expr), AV_OPT_TYPE_STRING, {.str=NULL}, CHAR_MIN, CHAR_MAX, FLAGS },

+    { "c0_opacity",  "set color component #0 opacity", OFFSET(params[0].opacity), AV_OPT_TYPE_DOUBLE, {.dbl=1}, 0, 1, FLAGS },

+    { "c1_opacity",  "set color component #1 opacity", OFFSET(params[1].opacity), AV_OPT_TYPE_DOUBLE, {.dbl=1}, 0, 1, FLAGS },

+    { "c2_opacity",  "set color component #2 opacity", OFFSET(params[2].opacity), AV_OPT_TYPE_DOUBLE, {.dbl=1}, 0, 1, FLAGS },

+    { "c3_opacity",  "set color component #3 opacity", OFFSET(params[3].opacity), AV_OPT_TYPE_DOUBLE, {.dbl=1}, 0, 1, FLAGS },

+    { "all_opacity", "set opacity for all color components", OFFSET(all_opacity), AV_OPT_TYPE_DOUBLE, {.dbl=1}, 0, 1, FLAGS},

+    { NULL },

+};

+

+AVFILTER_DEFINE_CLASS(blend);

+

+static void blend_normal(const uint8_t *top, int top_linesize,

+                         const uint8_t *bottom, int bottom_linesize,

+                         uint8_t *dst, int dst_linesize,

+                         int width, int height, FilterParams *param)

+{

+    av_image_copy_plane(dst, dst_linesize, top, top_linesize, width, height);

+}

+

+#define DEFINE_BLEND(name, expr)                                      \

+static void blend_## name(const uint8_t *top, int top_linesize,       \

+                          const uint8_t *bottom, int bottom_linesize, \

+                          uint8_t *dst, int dst_linesize,             \

+                          int width, int height, FilterParams *param) \

+{                                                                     \

+    double opacity = param->opacity;                                  \

+    int i, j;                                                         \

+                                                                      \

+    for (i = 0; i < height; i++) {                                    \

+        for (j = 0; j < width; j++) {                                 \

+            dst[j] = top[j] + ((expr) - top[j]) * opacity;            \

+        }                                                             \

+        dst    += dst_linesize;                                       \

+        top    += top_linesize;                                       \

+        bottom += bottom_linesize;                                    \

+    }                                                                 \

+}

+

+#define A top[j]

+#define B bottom[j]

+

+#define MULTIPLY(x, a, b) (x * ((a * b) / 255))

+#define SCREEN(x, a, b)   (255 - x * ((255 - a) * (255 - b) / 255))

+#define BURN(a, b)        ((a == 0) ? a : FFMAX(0, 255 - ((255 - b) << 8) / a))

+#define DODGE(a, b)       ((a == 255) ? a : FFMIN(255, ((b << 8) / (255 - a))))

+

+DEFINE_BLEND(addition,   FFMIN(255, A + B))

+DEFINE_BLEND(average,    (A + B) / 2)

+DEFINE_BLEND(subtract,   FFMAX(0, A - B))

+DEFINE_BLEND(multiply,   MULTIPLY(1, A, B))

+DEFINE_BLEND(negation,   255 - FFABS(255 - A - B))

+DEFINE_BLEND(difference, FFABS(A - B))

+DEFINE_BLEND(screen,     SCREEN(1, A, B))

+DEFINE_BLEND(overlay,    (A < 128) ? MULTIPLY(2, A, B) : SCREEN(2, A, B))

+DEFINE_BLEND(hardlight,  (B < 128) ? MULTIPLY(2, B, A) : SCREEN(2, B, A))

+DEFINE_BLEND(darken,     FFMIN(A, B))

+DEFINE_BLEND(lighten,    FFMAX(A, B))

+DEFINE_BLEND(divide,     ((float)A / ((float)B) * 255))

+DEFINE_BLEND(dodge,      DODGE(A, B))

+DEFINE_BLEND(burn,       BURN(A, B))

+DEFINE_BLEND(softlight,  (A > 127) ? B + (255 - B) * (A - 127.5) / 127.5 * (0.5 - FFABS(B - 127.5) / 255): B - B * ((127.5 - A) / 127.5) * (0.5 - FFABS(B - 127.5)/255))

+DEFINE_BLEND(exclusion,  A + B - 2 * A * B / 255)

+DEFINE_BLEND(pinlight,   (B < 128) ? FFMIN(A, 2 * B) : FFMAX(A, 2 * (B - 128)))

+DEFINE_BLEND(phoenix,    FFMIN(A, B) - FFMAX(A, B) + 255)

+DEFINE_BLEND(reflect,    (B == 255) ? B : FFMIN(255, (A * A / (255 - B))))

+DEFINE_BLEND(and,        A & B)

+DEFINE_BLEND(or,         A | B)

+DEFINE_BLEND(xor,        A ^ B)

+DEFINE_BLEND(vividlight, (B < 128) ? BURN(A, 2 * B) : DODGE(A, 2 * (B - 128)))

+

+static void blend_expr(const uint8_t *top, int top_linesize,

+                       const uint8_t *bottom, int bottom_linesize,

+                       uint8_t *dst, int dst_linesize,

+                       int width, int height,

+                       FilterParams *param)

+{

+    AVExpr *e = param->e;

+    double *values = param->values;

+    int y, x;

+

+    for (y = 0; y < height; y++) {

+        values[VAR_Y] = y;

+        for (x = 0; x < width; x++) {

+            values[VAR_X]      = x;

+            values[VAR_TOP]    = values[VAR_A] = top[x];

+            values[VAR_BOTTOM] = values[VAR_B] = bottom[x];

+            dst[x] = av_expr_eval(e, values, NULL);

+        }

+        dst    += dst_linesize;

+        top    += top_linesize;

+        bottom += bottom_linesize;

+    }

+}

+

+static av_cold int init(AVFilterContext *ctx, const char *args)

+{

+    BlendContext *b = ctx->priv;

+    int ret, plane;

+

+    b->class = &blend_class;

+    av_opt_set_defaults(b);

+

+    if ((ret = av_set_options_string(b, args, "=", ":")) < 0)

+        return ret;

+

+    for (plane = 0; plane < FF_ARRAY_ELEMS(b->params); plane++) {

+        FilterParams *param = &b->params[plane];

+

+        if (b->all_mode >= 0)

+            param->mode = b->all_mode;

+        if (b->all_opacity < 1)

+            param->opacity = b->all_opacity;

+

+        switch (param->mode) {

+        case BLEND_ADDITION:   param->blend = blend_addition;   break;

+        case BLEND_AND:        param->blend = blend_and;        break;

+        case BLEND_AVERAGE:    param->blend = blend_average;    break;

+        case BLEND_BURN:       param->blend = blend_burn;       break;

+        case BLEND_DARKEN:     param->blend = blend_darken;     break;

+        case BLEND_DIFFERENCE: param->blend = blend_difference; break;

+        case BLEND_DIVIDE:     param->blend = blend_divide;     break;

+        case BLEND_DODGE:      param->blend = blend_dodge;      break;

+        case BLEND_EXCLUSION:  param->blend = blend_exclusion;  break;

+        case BLEND_HARDLIGHT:  param->blend = blend_hardlight;  break;

+        case BLEND_LIGHTEN:    param->blend = blend_lighten;    break;

+        case BLEND_MULTIPLY:   param->blend = blend_multiply;   break;

+        case BLEND_NEGATION:   param->blend = blend_negation;   break;

+        case BLEND_NORMAL:     param->blend = blend_normal;     break;

+        case BLEND_OR:         param->blend = blend_or;         break;

+        case BLEND_OVERLAY:    param->blend = blend_overlay;    break;

+        case BLEND_PHOENIX:    param->blend = blend_phoenix;    break;

+        case BLEND_PINLIGHT:   param->blend = blend_pinlight;   break;

+        case BLEND_REFLECT:    param->blend = blend_reflect;    break;

+        case BLEND_SCREEN:     param->blend = blend_screen;     break;

+        case BLEND_SOFTLIGHT:  param->blend = blend_softlight;  break;

+        case BLEND_SUBTRACT:   param->blend = blend_subtract;   break;

+        case BLEND_VIVIDLIGHT: param->blend = blend_vividlight; break;

+        case BLEND_XOR:        param->blend = blend_xor;        break;

+        }

+

+        if (b->all_expr && !param->expr_str) {

+            param->expr_str = av_strdup(b->all_expr);

+            if (!param->expr_str)

+                return AVERROR(ENOMEM);

+        }

+        if (param->expr_str) {

+            ret = av_expr_parse(&param->e, param->expr_str, var_names,

+                                NULL, NULL, NULL, NULL, 0, ctx);

+            if (ret < 0)

+                return ret;

+            param->blend = blend_expr;

+        }

+    }

+

+    return 0;

+}

+

+static int query_formats(AVFilterContext *ctx)

+{

+    static const enum AVPixelFormat pix_fmts[] = {

+        AV_PIX_FMT_YUVA444P, AV_PIX_FMT_YUVA422P, AV_PIX_FMT_YUVA420P,

+        AV_PIX_FMT_YUV444P, AV_PIX_FMT_YUV422P, AV_PIX_FMT_YUV420P,

+        AV_PIX_FMT_GBRP, AV_PIX_FMT_GRAY8, AV_PIX_FMT_NONE

+    };

+

+    ff_set_common_formats(ctx, ff_make_format_list(pix_fmts));

+    return 0;

+}

+

+static int config_output(AVFilterLink *outlink)

+{

+    AVFilterContext *ctx = outlink->src;

+    AVFilterLink *toplink = ctx->inputs[TOP];

+    AVFilterLink *bottomlink = ctx->inputs[BOTTOM];

+

+    if (toplink->format != bottomlink->format) {

+        av_log(ctx, AV_LOG_ERROR, "inputs must be of same pixel format\n");

+        return AVERROR(EINVAL);

+    }

+    if (toplink->w                        != bottomlink->w ||

+        toplink->h                        != bottomlink->h ||

+        toplink->sample_aspect_ratio.num != bottomlink->sample_aspect_ratio.num ||

+        toplink->sample_aspect_ratio.den != bottomlink->sample_aspect_ratio.den) {

+        av_log(ctx, AV_LOG_ERROR, "First input link %s parameters "

+               "(size %dx%d, SAR %d:%d) do not match the corresponding "

+               "second input link %s parameters (%dx%d, SAR %d:%d)\n",

+               ctx->input_pads[TOP].name, toplink->w, toplink->h,

+               toplink->sample_aspect_ratio.num,

+               toplink->sample_aspect_ratio.den,

+               ctx->input_pads[BOTTOM].name, bottomlink->w, bottomlink->h,

+               bottomlink->sample_aspect_ratio.num,

+               bottomlink->sample_aspect_ratio.den);

+        return AVERROR(EINVAL);

+    }

+

+    outlink->w = toplink->w;

+    outlink->h = bottomlink->h;

+    outlink->time_base = toplink->time_base;

+    outlink->sample_aspect_ratio = toplink->sample_aspect_ratio;

+    outlink->frame_rate = toplink->frame_rate;

+    return 0;

+}

+

+static int config_input_top(AVFilterLink *inlink)

+{

+    BlendContext *b = inlink->dst->priv;

+    const AVPixFmtDescriptor *pix_desc = av_pix_fmt_desc_get(inlink->format);

+

+    b->hsub = pix_desc->log2_chroma_w;

+    b->vsub = pix_desc->log2_chroma_h;

+    return 0;

+}

+

+static av_cold void uninit(AVFilterContext *ctx)

+{

+    BlendContext *b = ctx->priv;

+    int i;

+

+    av_opt_free(b);

+    ff_bufqueue_discard_all(&b->queue_top);

+    ff_bufqueue_discard_all(&b->queue_bottom);

+

+    for (i = 0; i < FF_ARRAY_ELEMS(b->params); i++)

+        av_expr_free(b->params[i].e);

+}

+

+static int request_frame(AVFilterLink *outlink)

+{

+    AVFilterContext *ctx = outlink->src;

+    BlendContext *b = ctx->priv;

+    int in, ret;

+

+    b->frame_requested = 1;

+    while (b->frame_requested) {

+        in = ff_bufqueue_peek(&b->queue_top, TOP) ? BOTTOM : TOP;

+        ret = ff_request_frame(ctx->inputs[in]);

+        if (ret < 0)

+            return ret;

+    }

+    return 0;

+}

+

+static void blend_frame(AVFilterContext *ctx,

+                        AVFilterBufferRef *top_buf,

+                        AVFilterBufferRef *bottom_buf,

+                        AVFilterBufferRef *dst_buf)

+{

+    BlendContext *b = ctx->priv;

+    AVFilterLink *inlink = ctx->inputs[0];

+    FilterParams *param;

+    int plane;

+

+    for (plane = 0; dst_buf->data[plane]; plane++) {

+        int hsub = plane == 1 || plane == 2 ? b->hsub : 0;

+        int vsub = plane == 1 || plane == 2 ? b->vsub : 0;

+        int outw = dst_buf->video->w >> hsub;

+        int outh = dst_buf->video->h >> vsub;

+        uint8_t *dst    = dst_buf->data[plane];

+        uint8_t *top    = top_buf->data[plane];

+        uint8_t *bottom = bottom_buf->data[plane];

+

+        param = &b->params[plane];

+        param->values[VAR_T]  = dst_buf->pts == AV_NOPTS_VALUE ? NAN : dst_buf->pts * av_q2d(inlink->time_base);

+        param->values[VAR_W]  = outw;

+        param->values[VAR_H]  = outh;

+        param->values[VAR_SW] = outw / dst_buf->video->w;

+        param->values[VAR_SH] = outh / dst_buf->video->h;

+        param->blend(top, top_buf->linesize[plane],

+                     bottom, bottom_buf->linesize[plane],

+                     dst, dst_buf->linesize[plane], outw, outh, param);

+    }

+}

+

+static int filter_frame(AVFilterLink *inlink, AVFilterBufferRef *buf)

+{

+    AVFilterContext *ctx = inlink->dst;

+    AVFilterLink *outlink = ctx->outputs[0];

+    BlendContext *b = ctx->priv;

+

+    int ret = 0;

+    int is_bottom = (inlink == ctx->inputs[BOTTOM]);

+    struct FFBufQueue *queue =

+        (is_bottom ? &b->queue_bottom : &b->queue_top);

+    ff_bufqueue_add(ctx, queue, buf);

+

+    while (1) {

+        AVFilterBufferRef *top_buf, *bottom_buf, *out_buf;

+

+        if (!ff_bufqueue_peek(&b->queue_top, TOP) ||

+            !ff_bufqueue_peek(&b->queue_bottom, BOTTOM)) break;

+

+        top_buf = ff_bufqueue_get(&b->queue_top);

+        bottom_buf = ff_bufqueue_get(&b->queue_bottom);

+

+        out_buf = ff_get_video_buffer(outlink, AV_PERM_WRITE,

+                                      outlink->w, outlink->h);

+        if (!out_buf) {

+            return AVERROR(ENOMEM);

+        }

+        avfilter_copy_buffer_ref_props(out_buf, top_buf);

+

+        b->frame_requested = 0;

+        blend_frame(ctx, top_buf, bottom_buf, out_buf);

+        ret = ff_filter_frame(ctx->outputs[0], out_buf);

+        avfilter_unref_buffer(top_buf);

+        avfilter_unref_buffer(bottom_buf);

+    }

+    return ret;

+}

+

+static const AVFilterPad blend_inputs[] = {

+    {

+        .name             = "top",

+        .type             = AVMEDIA_TYPE_VIDEO,

+        .config_props     = config_input_top,

+        .filter_frame     = filter_frame,

+        .min_perms        = AV_PERM_READ | AV_PERM_PRESERVE,

+    },{

+        .name             = "bottom",

+        .type             = AVMEDIA_TYPE_VIDEO,

+        .filter_frame     = filter_frame,

+        .min_perms        = AV_PERM_READ | AV_PERM_PRESERVE,

+    },

+    { NULL }

+};

+

+static const AVFilterPad blend_outputs[] = {

+    {

+        .name          = "default",

+        .type          = AVMEDIA_TYPE_VIDEO,

+        .config_props  = config_output,

+        .request_frame = request_frame,

+    },

+    { NULL }

+};

+

+AVFilter avfilter_vf_blend = {

+    .name          = "blend",

+    .description   = NULL_IF_CONFIG_SMALL("Blend two video frames into each other."),

+    .init          = init,

+    .uninit        = uninit,

+    .priv_size     = sizeof(BlendContext),

+    .query_formats = query_formats,

+    .inputs        = blend_inputs,

+    .outputs       = blend_outputs,

+    .priv_class    = &blend_class,

+};