avfilter: Add 'drawgrid' video filter

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

MAINTAINERS

@@ -292,6 +292,7 @@ Filters:
   af_astreamsync.c                      Nicolas George
   af_atempo.c                           Pavel Koshevoy
   af_pan.c                              Nicolas George
+  vf_drawgrid.c                         Andrey Utkin
   vf_yadif.c                            Michael Niedermayer
 
 Sources:

doc/filters.texi

@@ -2870,6 +2870,45 @@ drawbox=x=10:y=10:w=100:h=100:color=pink@@0.5:t=max
 @end example
 @end itemize
 
+@section drawgrid
+
+Draw a grid on the input image.
+
+This filter accepts the following options:
+
+@table @option
+@item x
+@item y
+Specify the coordinates of some point of grid intersection (meant to configure offset). Both default to 0.
+
+@item width, w
+@item height, h
+Specify the width and height of the grid cell, if 0 they are interpreted as the
+input width and height, respectively, minus @code{thickness}, so image gets
+framed. Default to 0.
+
+@item color, c
+Specify the color of the grid, it can be the name of a color
+(case insensitive match) or a 0xRRGGBB[AA] sequence. If the special
+value @code{invert} is used, the grid color is the same as the
+video with inverted luma.
+Note that you can append opacity value (in range of 0.0 - 1.0)
+to color name after @@ sign.
+
+@item thickness, t
+Set the thickness of the grid line. Default value is @code{1}.
+@end table
+
+@subsection Examples
+
+@itemize
+@item
+Draw a grid with cell 100x100 pixels, thickness 2 pixels, with color red and an opacity of 50%:
+@example
+drawgrid=width=100:height=100:thickness=2:color=red@@0.5
+@end example
+@end itemize
+
 @anchor{drawtext}
 @section drawtext
 

libavfilter/Makefile

@@ -119,6 +119,7 @@ OBJS-$(CONFIG_DECIMATE_FILTER)               += vf_decimate.o
 OBJS-$(CONFIG_DELOGO_FILTER)                 += vf_delogo.o
 OBJS-$(CONFIG_DESHAKE_FILTER)                += vf_deshake.o
 OBJS-$(CONFIG_DRAWBOX_FILTER)                += vf_drawbox.o
+OBJS-$(CONFIG_DRAWGRID_FILTER)               += vf_drawgrid.o
 OBJS-$(CONFIG_DRAWTEXT_FILTER)               += vf_drawtext.o
 OBJS-$(CONFIG_EDGEDETECT_FILTER)             += vf_edgedetect.o
 OBJS-$(CONFIG_EXTRACTPLANES_FILTER)          += vf_extractplanes.o

libavfilter/allfilters.c

@@ -117,6 +117,7 @@ void avfilter_register_all(void)
     REGISTER_FILTER(DELOGO,         delogo,         vf);
     REGISTER_FILTER(DESHAKE,        deshake,        vf);
     REGISTER_FILTER(DRAWBOX,        drawbox,        vf);
+    REGISTER_FILTER(DRAWGRID,       drawgrid,       vf);
     REGISTER_FILTER(DRAWTEXT,       drawtext,       vf);
     REGISTER_FILTER(EDGEDETECT,     edgedetect,     vf);
     REGISTER_FILTER(EXTRACTPLANES,  extractplanes,  vf);

libavfilter/vf_drawgrid.c

@@ -0,0 +1,206 @@
+/*
+ * Copyright (c) 2008 Affine Systems, Inc (Michael Sullivan, Bobby Impollonia)
+ * Copyright (c) 2013 Andrey Utkin <andrey.krieger.utkin gmail com>
+ *
+ * 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
+ */
+
+/**
+ * @file
+ * Grid drawing filter.
+ * Code derived from drawbox filter.
+ */
+
+#include "libavutil/colorspace.h"
+#include "libavutil/common.h"
+#include "libavutil/opt.h"
+#include "libavutil/pixdesc.h"
+#include "libavutil/parseutils.h"
+#include "avfilter.h"
+#include "formats.h"
+#include "internal.h"
+#include "video.h"
+
+enum { Y, U, V, A };
+
+typedef struct {
+    const AVClass *class;
+    int x, y, w, h, thickness;
+    char *color_str;
+    unsigned char yuv_color[4];
+    int invert_color; ///< invert luma color
+    int vsub, hsub;   ///< chroma subsampling
+} DrawGridContext;
+
+static av_cold int init(AVFilterContext *ctx)
+{
+    DrawGridContext *drawgrid = ctx->priv;
+    uint8_t rgba_color[4];
+
+    if (!strcmp(drawgrid->color_str, "invert"))
+        drawgrid->invert_color = 1;
+    else if (av_parse_color(rgba_color, drawgrid->color_str, -1, ctx) < 0)
+        return AVERROR(EINVAL);
+
+    if (!drawgrid->invert_color) {
+        drawgrid->yuv_color[Y] = RGB_TO_Y_CCIR(rgba_color[0], rgba_color[1], rgba_color[2]);
+        drawgrid->yuv_color[U] = RGB_TO_U_CCIR(rgba_color[0], rgba_color[1], rgba_color[2], 0);
+        drawgrid->yuv_color[V] = RGB_TO_V_CCIR(rgba_color[0], rgba_color[1], rgba_color[2], 0);
+        drawgrid->yuv_color[A] = rgba_color[3];
+    }
+
+    return 0;
+}
+
+static int query_formats(AVFilterContext *ctx)
+{
+    static const enum AVPixelFormat pix_fmts[] = {
+        AV_PIX_FMT_YUV444P,  AV_PIX_FMT_YUV422P,  AV_PIX_FMT_YUV420P,
+        AV_PIX_FMT_YUV411P,  AV_PIX_FMT_YUV410P,
+        AV_PIX_FMT_YUVJ444P, AV_PIX_FMT_YUVJ422P, AV_PIX_FMT_YUVJ420P,
+        AV_PIX_FMT_YUV440P,  AV_PIX_FMT_YUVJ440P,
+        AV_PIX_FMT_NONE
+    };
+
+    ff_set_common_formats(ctx, ff_make_format_list(pix_fmts));
+    return 0;
+}
+
+static int config_input(AVFilterLink *inlink)
+{
+    DrawGridContext *drawgrid = inlink->dst->priv;
+    const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
+
+    drawgrid->hsub = desc->log2_chroma_w;
+    drawgrid->vsub = desc->log2_chroma_h;
+
+    if (drawgrid->w == 0) drawgrid->w = inlink->w - drawgrid->thickness;
+    if (drawgrid->h == 0) drawgrid->h = inlink->h - drawgrid->thickness;
+
+    av_log(inlink->dst, AV_LOG_VERBOSE, "x:%d y:%d w:%d h:%d color:0x%02X%02X%02X%02X\n",
+           drawgrid->x, drawgrid->y, drawgrid->w, drawgrid->h,
+           drawgrid->yuv_color[Y], drawgrid->yuv_color[U], drawgrid->yuv_color[V], drawgrid->yuv_color[A]);
+
+    return 0;
+}
+
+static av_pure av_always_inline int pixel_belongs_to_grid(DrawGridContext *drawgrid, int x, int y)
+{
+    // x is horizontal (width) coord,
+    // y is vertical (height) coord
+    int x_modulo;
+    int y_modulo;
+
+    // Abstract from the offset
+    x -= drawgrid->x;
+    y -= drawgrid->y;
+
+    x_modulo = x % drawgrid->w;
+    y_modulo = y % drawgrid->h;
+
+    // If x or y got negative, fix values to preserve logics
+    if (x_modulo < 0)
+        x_modulo += drawgrid->w;
+    if (y_modulo < 0)
+        y_modulo += drawgrid->h;
+
+    return x_modulo < drawgrid->thickness  // Belongs to vertical line
+        || y_modulo < drawgrid->thickness;  // Belongs to horizontal line
+}
+
+static int filter_frame(AVFilterLink *inlink, AVFrame *frame)
+{
+    DrawGridContext *drawgrid = inlink->dst->priv;
+    int plane, x, y;
+    uint8_t *row[4];
+
+    for (y = 0; y < frame->height; y++) {
+        row[0] = frame->data[0] + y * frame->linesize[0];
+
+        for (plane = 1; plane < 3; plane++)
+            row[plane] = frame->data[plane] +
+                 frame->linesize[plane] * (y >> drawgrid->vsub);
+
+        if (drawgrid->invert_color) {
+            for (x = 0; x < frame->width; x++)
+                if (pixel_belongs_to_grid(drawgrid, x, y))
+                    row[0][x] = 0xff - row[0][x];
+        } else {
+            for (x = 0; x < frame->width; x++) {
+                double alpha = (double)drawgrid->yuv_color[A] / 255;
+
+                if (pixel_belongs_to_grid(drawgrid, x, y)) {
+                    row[0][x                  ] = (1 - alpha) * row[0][x                  ] + alpha * drawgrid->yuv_color[Y];
+                    row[1][x >> drawgrid->hsub] = (1 - alpha) * row[1][x >> drawgrid->hsub] + alpha * drawgrid->yuv_color[U];
+                    row[2][x >> drawgrid->hsub] = (1 - alpha) * row[2][x >> drawgrid->hsub] + alpha * drawgrid->yuv_color[V];
+                }
+            }
+        }
+    }
+
+    return ff_filter_frame(inlink->dst->outputs[0], frame);
+}
+
+#define OFFSET(x) offsetof(DrawGridContext, x)
+#define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
+
+static const AVOption drawgrid_options[] = {
+    { "x",         "set horizontal offset",   OFFSET(x),         AV_OPT_TYPE_INT,    { .i64 = 0 },       INT_MIN,  INT_MAX,  FLAGS },
+    { "y",         "set vertical offset",     OFFSET(y),         AV_OPT_TYPE_INT,    { .i64 = 0 },       INT_MIN,  INT_MAX,  FLAGS },
+    { "width",     "set width of grid cell",  OFFSET(w),         AV_OPT_TYPE_INT,    { .i64 = 0 },       0,        INT_MAX,  FLAGS },
+    { "w",         "set width of grid cell",  OFFSET(w),         AV_OPT_TYPE_INT,    { .i64 = 0 },       0,        INT_MAX,  FLAGS },
+    { "height",    "set height of grid cell", OFFSET(h),         AV_OPT_TYPE_INT,    { .i64 = 0 },       0,        INT_MAX,  FLAGS },
+    { "h",         "set height of grid cell", OFFSET(h),         AV_OPT_TYPE_INT,    { .i64 = 0 },       0,        INT_MAX,  FLAGS },
+    { "color",     "set color of the grid",   OFFSET(color_str), AV_OPT_TYPE_STRING, { .str = "black" }, CHAR_MIN, CHAR_MAX, FLAGS },
+    { "c",         "set color of the grid",   OFFSET(color_str), AV_OPT_TYPE_STRING, { .str = "black" }, CHAR_MIN, CHAR_MAX, FLAGS },
+    { "thickness", "set grid line thickness", OFFSET(thickness), AV_OPT_TYPE_INT,    {.i64=1},           0,        INT_MAX,  FLAGS },
+    { "t",         "set grid line thickness", OFFSET(thickness), AV_OPT_TYPE_INT,    {.i64=1},           0,        INT_MAX,  FLAGS },
+    { NULL }
+};
+
+AVFILTER_DEFINE_CLASS(drawgrid);
+
+static const AVFilterPad avfilter_vf_drawgrid_inputs[] = {
+    {
+        .name           = "default",
+        .type           = AVMEDIA_TYPE_VIDEO,
+        .config_props   = config_input,
+        .filter_frame   = filter_frame,
+        .needs_writable = 1,
+    },
+    { NULL }
+};
+
+static const AVFilterPad avfilter_vf_drawgrid_outputs[] = {
+    {
+        .name = "default",
+        .type = AVMEDIA_TYPE_VIDEO,
+    },
+    { NULL }
+};
+
+AVFilter avfilter_vf_drawgrid = {
+    .name          = "drawgrid",
+    .description   = NULL_IF_CONFIG_SMALL("Draw a colored grid on the input video."),
+    .priv_size     = sizeof(DrawGridContext),
+    .priv_class    = &drawgrid_class,
+    .init          = init,
+    .query_formats = query_formats,
+    .inputs        = avfilter_vf_drawgrid_inputs,
+    .outputs       = avfilter_vf_drawgrid_outputs,
+    .flags         = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC,
+};