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  1. /*
  2.  * Copyright (c) 2013 Paul B Mahol
  3.  *
  4.  * This file is part of FFmpeg.
  5.  *
  6.  * FFmpeg is free software; you can redistribute it and/or
  7.  * modify it under the terms of the GNU Lesser General Public
  8.  * License as published by the Free Software Foundation; either
  9.  * version 2.1 of the License, or (at your option) any later version.
  10.  *
  11.  * FFmpeg is distributed in the hope that it will be useful,
  12.  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13.  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14.  * Lesser General Public License for more details.
  15.  *
  16.  * You should have received a copy of the GNU Lesser General Public
  17.  * License along with FFmpeg; if not, write to the Free Software
  18.  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  19.  */
  20.  
  21. #include "libavutil/imgutils.h"
  22. #include "libavutil/eval.h"
  23. #include "libavutil/opt.h"
  24. #include "libavutil/pixfmt.h"
  25. #include "avfilter.h"
  26. #include "bufferqueue.h"
  27. #include "formats.h"
  28. #include "internal.h"
  29. #include "dualinput.h"
  30. #include "video.h"
  31.  
  32. #define TOP    0
  33. #define BOTTOM 1
  34.  
  35. enum BlendMode {
  36.     BLEND_UNSET = -1,
  37.     BLEND_NORMAL,
  38.     BLEND_ADDITION,
  39.     BLEND_AND,
  40.     BLEND_AVERAGE,
  41.     BLEND_BURN,
  42.     BLEND_DARKEN,
  43.     BLEND_DIFFERENCE,
  44.     BLEND_DIVIDE,
  45.     BLEND_DODGE,
  46.     BLEND_EXCLUSION,
  47.     BLEND_HARDLIGHT,
  48.     BLEND_LIGHTEN,
  49.     BLEND_MULTIPLY,
  50.     BLEND_NEGATION,
  51.     BLEND_OR,
  52.     BLEND_OVERLAY,
  53.     BLEND_PHOENIX,
  54.     BLEND_PINLIGHT,
  55.     BLEND_REFLECT,
  56.     BLEND_SCREEN,
  57.     BLEND_SOFTLIGHT,
  58.     BLEND_SUBTRACT,
  59.     BLEND_VIVIDLIGHT,
  60.     BLEND_XOR,
  61.     BLEND_NB
  62. };
  63.  
  64. static const char *const var_names[] = {   "X",   "Y",   "W",   "H",   "SW",   "SH",   "T",   "N",   "A",   "B",   "TOP",   "BOTTOM",        NULL };
  65. enum                                   { VAR_X, VAR_Y, VAR_W, VAR_H, VAR_SW, VAR_SH, VAR_T, VAR_N, VAR_A, VAR_B, VAR_TOP, VAR_BOTTOM, VAR_VARS_NB };
  66.  
  67. typedef struct FilterParams {
  68.     enum BlendMode mode;
  69.     double opacity;
  70.     AVExpr *e;
  71.     char *expr_str;
  72.     void (*blend)(const uint8_t *top, int top_linesize,
  73.                   const uint8_t *bottom, int bottom_linesize,
  74.                   uint8_t *dst, int dst_linesize,
  75.                   int width, int start, int end,
  76.                   struct FilterParams *param, double *values);
  77. } FilterParams;
  78.  
  79. typedef struct ThreadData {
  80.     const AVFrame *top, *bottom;
  81.     AVFrame *dst;
  82.     AVFilterLink *inlink;
  83.     int plane;
  84.     int w, h;
  85.     FilterParams *param;
  86. } ThreadData;
  87.  
  88. typedef struct {
  89.     const AVClass *class;
  90.     FFDualInputContext dinput;
  91.     int hsub, vsub;             ///< chroma subsampling values
  92.     int nb_planes;
  93.     char *all_expr;
  94.     enum BlendMode all_mode;
  95.     double all_opacity;
  96.  
  97.     FilterParams params[4];
  98. } BlendContext;
  99.  
  100. #define OFFSET(x) offsetof(BlendContext, x)
  101. #define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
  102.  
  103. static const AVOption blend_options[] = {
  104.     { "c0_mode", "set component #0 blend mode", OFFSET(params[0].mode), AV_OPT_TYPE_INT, {.i64=0}, 0, BLEND_NB-1, FLAGS, "mode"},
  105.     { "c1_mode", "set component #1 blend mode", OFFSET(params[1].mode), AV_OPT_TYPE_INT, {.i64=0}, 0, BLEND_NB-1, FLAGS, "mode"},
  106.     { "c2_mode", "set component #2 blend mode", OFFSET(params[2].mode), AV_OPT_TYPE_INT, {.i64=0}, 0, BLEND_NB-1, FLAGS, "mode"},
  107.     { "c3_mode", "set component #3 blend mode", OFFSET(params[3].mode), AV_OPT_TYPE_INT, {.i64=0}, 0, BLEND_NB-1, FLAGS, "mode"},
  108.     { "all_mode", "set blend mode for all components", OFFSET(all_mode), AV_OPT_TYPE_INT, {.i64=-1},-1, BLEND_NB-1, FLAGS, "mode"},
  109.     { "addition",   "", 0, AV_OPT_TYPE_CONST, {.i64=BLEND_ADDITION},   0, 0, FLAGS, "mode" },
  110.     { "and",        "", 0, AV_OPT_TYPE_CONST, {.i64=BLEND_AND},        0, 0, FLAGS, "mode" },
  111.     { "average",    "", 0, AV_OPT_TYPE_CONST, {.i64=BLEND_AVERAGE},    0, 0, FLAGS, "mode" },
  112.     { "burn",       "", 0, AV_OPT_TYPE_CONST, {.i64=BLEND_BURN},       0, 0, FLAGS, "mode" },
  113.     { "darken",     "", 0, AV_OPT_TYPE_CONST, {.i64=BLEND_DARKEN},     0, 0, FLAGS, "mode" },
  114.     { "difference", "", 0, AV_OPT_TYPE_CONST, {.i64=BLEND_DIFFERENCE}, 0, 0, FLAGS, "mode" },
  115.     { "divide",     "", 0, AV_OPT_TYPE_CONST, {.i64=BLEND_DIVIDE},     0, 0, FLAGS, "mode" },
  116.     { "dodge",      "", 0, AV_OPT_TYPE_CONST, {.i64=BLEND_DODGE},      0, 0, FLAGS, "mode" },
  117.     { "exclusion",  "", 0, AV_OPT_TYPE_CONST, {.i64=BLEND_EXCLUSION},  0, 0, FLAGS, "mode" },
  118.     { "hardlight",  "", 0, AV_OPT_TYPE_CONST, {.i64=BLEND_HARDLIGHT},  0, 0, FLAGS, "mode" },
  119.     { "lighten",    "", 0, AV_OPT_TYPE_CONST, {.i64=BLEND_LIGHTEN},    0, 0, FLAGS, "mode" },
  120.     { "multiply",   "", 0, AV_OPT_TYPE_CONST, {.i64=BLEND_MULTIPLY},   0, 0, FLAGS, "mode" },
  121.     { "negation",   "", 0, AV_OPT_TYPE_CONST, {.i64=BLEND_NEGATION},   0, 0, FLAGS, "mode" },
  122.     { "normal",     "", 0, AV_OPT_TYPE_CONST, {.i64=BLEND_NORMAL},     0, 0, FLAGS, "mode" },
  123.     { "or",         "", 0, AV_OPT_TYPE_CONST, {.i64=BLEND_OR},         0, 0, FLAGS, "mode" },
  124.     { "overlay",    "", 0, AV_OPT_TYPE_CONST, {.i64=BLEND_OVERLAY},    0, 0, FLAGS, "mode" },
  125.     { "phoenix",    "", 0, AV_OPT_TYPE_CONST, {.i64=BLEND_PHOENIX},    0, 0, FLAGS, "mode" },
  126.     { "pinlight",   "", 0, AV_OPT_TYPE_CONST, {.i64=BLEND_PINLIGHT},   0, 0, FLAGS, "mode" },
  127.     { "reflect",    "", 0, AV_OPT_TYPE_CONST, {.i64=BLEND_REFLECT},    0, 0, FLAGS, "mode" },
  128.     { "screen",     "", 0, AV_OPT_TYPE_CONST, {.i64=BLEND_SCREEN},     0, 0, FLAGS, "mode" },
  129.     { "softlight",  "", 0, AV_OPT_TYPE_CONST, {.i64=BLEND_SOFTLIGHT},  0, 0, FLAGS, "mode" },
  130.     { "subtract",   "", 0, AV_OPT_TYPE_CONST, {.i64=BLEND_SUBTRACT},   0, 0, FLAGS, "mode" },
  131.     { "vividlight", "", 0, AV_OPT_TYPE_CONST, {.i64=BLEND_VIVIDLIGHT}, 0, 0, FLAGS, "mode" },
  132.     { "xor",        "", 0, AV_OPT_TYPE_CONST, {.i64=BLEND_XOR},        0, 0, FLAGS, "mode" },
  133.     { "c0_expr",  "set color component #0 expression", OFFSET(params[0].expr_str), AV_OPT_TYPE_STRING, {.str=NULL}, CHAR_MIN, CHAR_MAX, FLAGS },
  134.     { "c1_expr",  "set color component #1 expression", OFFSET(params[1].expr_str), AV_OPT_TYPE_STRING, {.str=NULL}, CHAR_MIN, CHAR_MAX, FLAGS },
  135.     { "c2_expr",  "set color component #2 expression", OFFSET(params[2].expr_str), AV_OPT_TYPE_STRING, {.str=NULL}, CHAR_MIN, CHAR_MAX, FLAGS },
  136.     { "c3_expr",  "set color component #3 expression", OFFSET(params[3].expr_str), AV_OPT_TYPE_STRING, {.str=NULL}, CHAR_MIN, CHAR_MAX, FLAGS },
  137.     { "all_expr", "set expression for all color components", OFFSET(all_expr), AV_OPT_TYPE_STRING, {.str=NULL}, CHAR_MIN, CHAR_MAX, FLAGS },
  138.     { "c0_opacity",  "set color component #0 opacity", OFFSET(params[0].opacity), AV_OPT_TYPE_DOUBLE, {.dbl=1}, 0, 1, FLAGS },
  139.     { "c1_opacity",  "set color component #1 opacity", OFFSET(params[1].opacity), AV_OPT_TYPE_DOUBLE, {.dbl=1}, 0, 1, FLAGS },
  140.     { "c2_opacity",  "set color component #2 opacity", OFFSET(params[2].opacity), AV_OPT_TYPE_DOUBLE, {.dbl=1}, 0, 1, FLAGS },
  141.     { "c3_opacity",  "set color component #3 opacity", OFFSET(params[3].opacity), AV_OPT_TYPE_DOUBLE, {.dbl=1}, 0, 1, FLAGS },
  142.     { "all_opacity", "set opacity for all color components", OFFSET(all_opacity), AV_OPT_TYPE_DOUBLE, {.dbl=1}, 0, 1, FLAGS},
  143.     { "shortest",    "force termination when the shortest input terminates", OFFSET(dinput.shortest), AV_OPT_TYPE_INT, {.i64=0}, 0, 1, FLAGS },
  144.     { "repeatlast",  "repeat last bottom frame", OFFSET(dinput.repeatlast), AV_OPT_TYPE_INT, {.i64=1}, 0, 1, FLAGS },
  145.     { NULL }
  146. };
  147.  
  148. AVFILTER_DEFINE_CLASS(blend);
  149.  
  150. static void blend_normal(const uint8_t *top, int top_linesize,
  151.                          const uint8_t *bottom, int bottom_linesize,
  152.                          uint8_t *dst, int dst_linesize,
  153.                          int width, int start, int end,
  154.                          FilterParams *param, double *values)
  155. {
  156.     av_image_copy_plane(dst, dst_linesize, top, top_linesize, width, end - start);
  157. }
  158.  
  159. #define DEFINE_BLEND(name, expr)                                      \
  160. static void blend_## name(const uint8_t *top, int top_linesize,       \
  161.                           const uint8_t *bottom, int bottom_linesize, \
  162.                           uint8_t *dst, int dst_linesize,             \
  163.                           int width, int start, int end,              \
  164.                           FilterParams *param, double *values)        \
  165. {                                                                     \
  166.     double opacity = param->opacity;                                  \
  167.     int i, j;                                                         \
  168.                                                                       \
  169.     for (i = start; i < end; i++) {                                   \
  170.         for (j = 0; j < width; j++) {                                 \
  171.             dst[j] = top[j] + ((expr) - top[j]) * opacity;            \
  172.         }                                                             \
  173.         dst    += dst_linesize;                                       \
  174.         top    += top_linesize;                                       \
  175.         bottom += bottom_linesize;                                    \
  176.     }                                                                 \
  177. }
  178.  
  179. #define A top[j]
  180. #define B bottom[j]
  181.  
  182. #define MULTIPLY(x, a, b) (x * ((a * b) / 255))
  183. #define SCREEN(x, a, b)   (255 - x * ((255 - a) * (255 - b) / 255))
  184. #define BURN(a, b)        ((a == 0) ? a : FFMAX(0, 255 - ((255 - b) << 8) / a))
  185. #define DODGE(a, b)       ((a == 255) ? a : FFMIN(255, ((b << 8) / (255 - a))))
  186.  
  187. DEFINE_BLEND(addition,   FFMIN(255, A + B))
  188. DEFINE_BLEND(average,    (A + B) / 2)
  189. DEFINE_BLEND(subtract,   FFMAX(0, A - B))
  190. DEFINE_BLEND(multiply,   MULTIPLY(1, A, B))
  191. DEFINE_BLEND(negation,   255 - FFABS(255 - A - B))
  192. DEFINE_BLEND(difference, FFABS(A - B))
  193. DEFINE_BLEND(screen,     SCREEN(1, A, B))
  194. DEFINE_BLEND(overlay,    (A < 128) ? MULTIPLY(2, A, B) : SCREEN(2, A, B))
  195. DEFINE_BLEND(hardlight,  (B < 128) ? MULTIPLY(2, B, A) : SCREEN(2, B, A))
  196. DEFINE_BLEND(darken,     FFMIN(A, B))
  197. DEFINE_BLEND(lighten,    FFMAX(A, B))
  198. DEFINE_BLEND(divide,     ((float)A / ((float)B) * 255))
  199. DEFINE_BLEND(dodge,      DODGE(A, B))
  200. DEFINE_BLEND(burn,       BURN(A, B))
  201. 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))
  202. DEFINE_BLEND(exclusion,  A + B - 2 * A * B / 255)
  203. DEFINE_BLEND(pinlight,   (B < 128) ? FFMIN(A, 2 * B) : FFMAX(A, 2 * (B - 128)))
  204. DEFINE_BLEND(phoenix,    FFMIN(A, B) - FFMAX(A, B) + 255)
  205. DEFINE_BLEND(reflect,    (B == 255) ? B : FFMIN(255, (A * A / (255 - B))))
  206. DEFINE_BLEND(and,        A & B)
  207. DEFINE_BLEND(or,         A | B)
  208. DEFINE_BLEND(xor,        A ^ B)
  209. DEFINE_BLEND(vividlight, (B < 128) ? BURN(A, 2 * B) : DODGE(A, 2 * (B - 128)))
  210.  
  211. static void blend_expr(const uint8_t *top, int top_linesize,
  212.                        const uint8_t *bottom, int bottom_linesize,
  213.                        uint8_t *dst, int dst_linesize,
  214.                        int width, int start, int end,
  215.                        FilterParams *param, double *values)
  216. {
  217.     AVExpr *e = param->e;
  218.     int y, x;
  219.  
  220.     for (y = start; y < end; y++) {
  221.         values[VAR_Y] = y;
  222.         for (x = 0; x < width; x++) {
  223.             values[VAR_X]      = x;
  224.             values[VAR_TOP]    = values[VAR_A] = top[x];
  225.             values[VAR_BOTTOM] = values[VAR_B] = bottom[x];
  226.             dst[x] = av_expr_eval(e, values, NULL);
  227.         }
  228.         dst    += dst_linesize;
  229.         top    += top_linesize;
  230.         bottom += bottom_linesize;
  231.     }
  232. }
  233.  
  234. static int filter_slice(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)
  235. {
  236.     ThreadData *td = arg;
  237.     int slice_start = (td->h *  jobnr   ) / nb_jobs;
  238.     int slice_end   = (td->h * (jobnr+1)) / nb_jobs;
  239.     const uint8_t *top    = td->top->data[td->plane];
  240.     const uint8_t *bottom = td->bottom->data[td->plane];
  241.     uint8_t *dst    = td->dst->data[td->plane];
  242.     double values[VAR_VARS_NB];
  243.  
  244.     values[VAR_N]  = td->inlink->frame_count;
  245.     values[VAR_T]  = td->dst->pts == AV_NOPTS_VALUE ? NAN : td->dst->pts * av_q2d(td->inlink->time_base);
  246.     values[VAR_W]  = td->w;
  247.     values[VAR_H]  = td->h;
  248.     values[VAR_SW] = td->w / (double)td->dst->width;
  249.     values[VAR_SH] = td->h / (double)td->dst->height;
  250.  
  251.     td->param->blend(top + slice_start * td->top->linesize[td->plane],
  252.                      td->top->linesize[td->plane],
  253.                      bottom + slice_start * td->bottom->linesize[td->plane],
  254.                      td->bottom->linesize[td->plane],
  255.                      dst + slice_start * td->dst->linesize[td->plane],
  256.                      td->dst->linesize[td->plane],
  257.                      td->w, slice_start, slice_end, td->param, &values[0]);
  258.     return 0;
  259. }
  260.  
  261. static AVFrame *blend_frame(AVFilterContext *ctx, AVFrame *top_buf,
  262.                             const AVFrame *bottom_buf)
  263. {
  264.     BlendContext *b = ctx->priv;
  265.     AVFilterLink *inlink = ctx->inputs[0];
  266.     AVFilterLink *outlink = ctx->outputs[0];
  267.     AVFrame *dst_buf;
  268.     int plane;
  269.  
  270.     dst_buf = ff_get_video_buffer(outlink, outlink->w, outlink->h);
  271.     if (!dst_buf)
  272.         return top_buf;
  273.     av_frame_copy_props(dst_buf, top_buf);
  274.  
  275.     for (plane = 0; plane < b->nb_planes; plane++) {
  276.         int hsub = plane == 1 || plane == 2 ? b->hsub : 0;
  277.         int vsub = plane == 1 || plane == 2 ? b->vsub : 0;
  278.         int outw = FF_CEIL_RSHIFT(dst_buf->width,  hsub);
  279.         int outh = FF_CEIL_RSHIFT(dst_buf->height, vsub);
  280.         FilterParams *param = &b->params[plane];
  281.         ThreadData td = { .top = top_buf, .bottom = bottom_buf, .dst = dst_buf,
  282.                           .w = outw, .h = outh, .param = param, .plane = plane,
  283.                           .inlink = inlink };
  284.  
  285.         ctx->internal->execute(ctx, filter_slice, &td, NULL, FFMIN(outh, ctx->graph->nb_threads));
  286.     }
  287.  
  288.     av_frame_free(&top_buf);
  289.  
  290.     return dst_buf;
  291. }
  292.  
  293. static av_cold int init(AVFilterContext *ctx)
  294. {
  295.     BlendContext *b = ctx->priv;
  296.     int ret, plane;
  297.  
  298.     for (plane = 0; plane < FF_ARRAY_ELEMS(b->params); plane++) {
  299.         FilterParams *param = &b->params[plane];
  300.  
  301.         if (b->all_mode >= 0)
  302.             param->mode = b->all_mode;
  303.         if (b->all_opacity < 1)
  304.             param->opacity = b->all_opacity;
  305.  
  306.         switch (param->mode) {
  307.         case BLEND_ADDITION:   param->blend = blend_addition;   break;
  308.         case BLEND_AND:        param->blend = blend_and;        break;
  309.         case BLEND_AVERAGE:    param->blend = blend_average;    break;
  310.         case BLEND_BURN:       param->blend = blend_burn;       break;
  311.         case BLEND_DARKEN:     param->blend = blend_darken;     break;
  312.         case BLEND_DIFFERENCE: param->blend = blend_difference; break;
  313.         case BLEND_DIVIDE:     param->blend = blend_divide;     break;
  314.         case BLEND_DODGE:      param->blend = blend_dodge;      break;
  315.         case BLEND_EXCLUSION:  param->blend = blend_exclusion;  break;
  316.         case BLEND_HARDLIGHT:  param->blend = blend_hardlight;  break;
  317.         case BLEND_LIGHTEN:    param->blend = blend_lighten;    break;
  318.         case BLEND_MULTIPLY:   param->blend = blend_multiply;   break;
  319.         case BLEND_NEGATION:   param->blend = blend_negation;   break;
  320.         case BLEND_NORMAL:     param->blend = blend_normal;     break;
  321.         case BLEND_OR:         param->blend = blend_or;         break;
  322.         case BLEND_OVERLAY:    param->blend = blend_overlay;    break;
  323.         case BLEND_PHOENIX:    param->blend = blend_phoenix;    break;
  324.         case BLEND_PINLIGHT:   param->blend = blend_pinlight;   break;
  325.         case BLEND_REFLECT:    param->blend = blend_reflect;    break;
  326.         case BLEND_SCREEN:     param->blend = blend_screen;     break;
  327.         case BLEND_SOFTLIGHT:  param->blend = blend_softlight;  break;
  328.         case BLEND_SUBTRACT:   param->blend = blend_subtract;   break;
  329.         case BLEND_VIVIDLIGHT: param->blend = blend_vividlight; break;
  330.         case BLEND_XOR:        param->blend = blend_xor;        break;
  331.         }
  332.  
  333.         if (b->all_expr && !param->expr_str) {
  334.             param->expr_str = av_strdup(b->all_expr);
  335.             if (!param->expr_str)
  336.                 return AVERROR(ENOMEM);
  337.         }
  338.         if (param->expr_str) {
  339.             ret = av_expr_parse(&param->e, param->expr_str, var_names,
  340.                                 NULL, NULL, NULL, NULL, 0, ctx);
  341.             if (ret < 0)
  342.                 return ret;
  343.             param->blend = blend_expr;
  344.         }
  345.     }
  346.  
  347.     b->dinput.process = blend_frame;
  348.     return 0;
  349. }
  350.  
  351. static int query_formats(AVFilterContext *ctx)
  352. {
  353.     static const enum AVPixelFormat pix_fmts[] = {
  354.         AV_PIX_FMT_YUVA444P, AV_PIX_FMT_YUVA422P, AV_PIX_FMT_YUVA420P,
  355.         AV_PIX_FMT_YUVJ444P, AV_PIX_FMT_YUVJ440P, AV_PIX_FMT_YUVJ422P,AV_PIX_FMT_YUVJ420P, AV_PIX_FMT_YUVJ411P,
  356.         AV_PIX_FMT_YUV444P, AV_PIX_FMT_YUV440P, AV_PIX_FMT_YUV422P, AV_PIX_FMT_YUV420P, AV_PIX_FMT_YUV411P, AV_PIX_FMT_YUV410P,
  357.         AV_PIX_FMT_GBRP, AV_PIX_FMT_GBRAP, AV_PIX_FMT_GRAY8, AV_PIX_FMT_NONE
  358.     };
  359.  
  360.     ff_set_common_formats(ctx, ff_make_format_list(pix_fmts));
  361.     return 0;
  362. }
  363.  
  364. static int config_output(AVFilterLink *outlink)
  365. {
  366.     AVFilterContext *ctx = outlink->src;
  367.     AVFilterLink *toplink = ctx->inputs[TOP];
  368.     AVFilterLink *bottomlink = ctx->inputs[BOTTOM];
  369.     BlendContext *b = ctx->priv;
  370.     const AVPixFmtDescriptor *pix_desc = av_pix_fmt_desc_get(toplink->format);
  371.     int ret;
  372.  
  373.     if (toplink->format != bottomlink->format) {
  374.         av_log(ctx, AV_LOG_ERROR, "inputs must be of same pixel format\n");
  375.         return AVERROR(EINVAL);
  376.     }
  377.     if (toplink->w                       != bottomlink->w ||
  378.         toplink->h                       != bottomlink->h ||
  379.         toplink->sample_aspect_ratio.num != bottomlink->sample_aspect_ratio.num ||
  380.         toplink->sample_aspect_ratio.den != bottomlink->sample_aspect_ratio.den) {
  381.         av_log(ctx, AV_LOG_ERROR, "First input link %s parameters "
  382.                "(size %dx%d, SAR %d:%d) do not match the corresponding "
  383.                "second input link %s parameters (%dx%d, SAR %d:%d)\n",
  384.                ctx->input_pads[TOP].name, toplink->w, toplink->h,
  385.                toplink->sample_aspect_ratio.num,
  386.                toplink->sample_aspect_ratio.den,
  387.                ctx->input_pads[BOTTOM].name, bottomlink->w, bottomlink->h,
  388.                bottomlink->sample_aspect_ratio.num,
  389.                bottomlink->sample_aspect_ratio.den);
  390.         return AVERROR(EINVAL);
  391.     }
  392.  
  393.     outlink->w = toplink->w;
  394.     outlink->h = toplink->h;
  395.     outlink->time_base = toplink->time_base;
  396.     outlink->sample_aspect_ratio = toplink->sample_aspect_ratio;
  397.     outlink->frame_rate = toplink->frame_rate;
  398.  
  399.     b->hsub = pix_desc->log2_chroma_w;
  400.     b->vsub = pix_desc->log2_chroma_h;
  401.     b->nb_planes = av_pix_fmt_count_planes(toplink->format);
  402.  
  403.     if ((ret = ff_dualinput_init(ctx, &b->dinput)) < 0)
  404.         return ret;
  405.  
  406.     return 0;
  407. }
  408.  
  409. static av_cold void uninit(AVFilterContext *ctx)
  410. {
  411.     BlendContext *b = ctx->priv;
  412.     int i;
  413.  
  414.     ff_dualinput_uninit(&b->dinput);
  415.     for (i = 0; i < FF_ARRAY_ELEMS(b->params); i++)
  416.         av_expr_free(b->params[i].e);
  417. }
  418.  
  419. static int request_frame(AVFilterLink *outlink)
  420. {
  421.     BlendContext *b = outlink->src->priv;
  422.     return ff_dualinput_request_frame(&b->dinput, outlink);
  423. }
  424.  
  425. static int filter_frame(AVFilterLink *inlink, AVFrame *buf)
  426. {
  427.     BlendContext *b = inlink->dst->priv;
  428.     return ff_dualinput_filter_frame(&b->dinput, inlink, buf);
  429. }
  430.  
  431. static const AVFilterPad blend_inputs[] = {
  432.     {
  433.         .name          = "top",
  434.         .type          = AVMEDIA_TYPE_VIDEO,
  435.         .filter_frame  = filter_frame,
  436.     },{
  437.         .name          = "bottom",
  438.         .type          = AVMEDIA_TYPE_VIDEO,
  439.         .filter_frame  = filter_frame,
  440.     },
  441.     { NULL }
  442. };
  443.  
  444. static const AVFilterPad blend_outputs[] = {
  445.     {
  446.         .name          = "default",
  447.         .type          = AVMEDIA_TYPE_VIDEO,
  448.         .config_props  = config_output,
  449.         .request_frame = request_frame,
  450.     },
  451.     { NULL }
  452. };
  453.  
  454. AVFilter avfilter_vf_blend = {
  455.     .name          = "blend",
  456.     .description   = NULL_IF_CONFIG_SMALL("Blend two video frames into each other."),
  457.     .init          = init,
  458.     .uninit        = uninit,
  459.     .priv_size     = sizeof(BlendContext),
  460.     .query_formats = query_formats,
  461.     .inputs        = blend_inputs,
  462.     .outputs       = blend_outputs,
  463.     .priv_class    = &blend_class,
  464.     .flags         = AVFILTER_FLAG_SUPPORT_TIMELINE_INTERNAL | AVFILTER_FLAG_SLICE_THREADS,
  465. };
  466.