[FFmpeg-devel] [PATCH] histogram filter

Paul B Mahol onemda at gmail.com
Wed Jan 30 00:08:55 CET 2013


Signed-off-by: Paul B Mahol <onemda at gmail.com>
---
 doc/filters.texi           |  67 ++++++++++
 libavfilter/Makefile       |   1 +
 libavfilter/allfilters.c   |   1 +
 libavfilter/vf_histogram.c | 313 +++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 382 insertions(+)
 create mode 100644 libavfilter/vf_histogram.c

diff --git a/doc/filters.texi b/doc/filters.texi
index 21e2cff..a417ca1 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -2796,6 +2796,73 @@ the histogram. Possible values are @code{none}, @code{weak} or
 @code{strong}. It defaults to @code{none}.
 @end table
 
+ at section histogram
+
+Compute and draw an histogram.
+
+Computed histogram is representation of distribution of color components
+in an image.
+
+The filter accepts the following named parameters:
+
+ at table @option
+ at item graph
+Draw histogram graph, defaults to enabled, otherwise dumps
+histogram values to output.
+
+ at item mode
+Set histogram mode, defaults to @code{histogram}. Other possible
+mode is @code{scope}.
+
+ at item size
+Set the video size, the value must be a valid abbreviation or in the
+form @var{width}x at var{height}. Minimum allowed value is 256x256.
+Note that @code{scope} mode will have most useful results if @var{width}
+is multiple of 256.
+
+ at item fg
+Set foreground histogram color. Only used in @code{histogram}.
+
+ at item bg
+Set background histogram color. Only used in @code{histogram}.
+ at end table
+
+Following options specify which color components are used in histogram calculation:
+
+ at table @option
+ at item @var{y} (Y/luminance component)
+ at item @var{u} (U/Cb component)
+ at item @var{v} (V/Cr component)
+ at item @var{a} (alpha component)
+ at item @var{r} (red component)
+ at item @var{g} (green component)
+ at item @var{b} (blue component)
+ at end table
+
+ at subsection Examples
+
+ at itemize
+
+ at item
+Calculate and draw histogram for luma plane:
+ at example
+ffplay -i input -vf format=yuva444p,histogram=fg=yellow:bg=white
+ at end example
+
+ at item
+Calculate and draw histogram for chroma planes:
+ at example
+ffplay -i input -vf format=yuva444p,histogram=y=0:u=1:v=1:a=0
+ at end example
+
+ at item
+Calculate and draw histogram for green plane only:
+ at example
+ffplay -i input -vf format=rgba,histogram=r=0:g=1:b=0:a=0
+ at end example
+
+ at end itemize
+
 @section hqdn3d
 
 High precision/quality 3d denoise filter. This filter aims to reduce
diff --git a/libavfilter/Makefile b/libavfilter/Makefile
index 5835a7e..13bcaf3 100644
--- a/libavfilter/Makefile
+++ b/libavfilter/Makefile
@@ -113,6 +113,7 @@ OBJS-$(CONFIG_GEQ_FILTER)                    += vf_geq.o
 OBJS-$(CONFIG_GRADFUN_FILTER)                += vf_gradfun.o
 OBJS-$(CONFIG_HFLIP_FILTER)                  += vf_hflip.o
 OBJS-$(CONFIG_HISTEQ_FILTER)                 += vf_histeq.o
+OBJS-$(CONFIG_HISTOGRAM_FILTER)              += vf_histogram.o
 OBJS-$(CONFIG_HQDN3D_FILTER)                 += vf_hqdn3d.o
 OBJS-$(CONFIG_HUE_FILTER)                    += vf_hue.o
 OBJS-$(CONFIG_IDET_FILTER)                   += vf_idet.o
diff --git a/libavfilter/allfilters.c b/libavfilter/allfilters.c
index 24df561..71922b5 100644
--- a/libavfilter/allfilters.c
+++ b/libavfilter/allfilters.c
@@ -107,6 +107,7 @@ void avfilter_register_all(void)
     REGISTER_FILTER(GRADFUN,        gradfun,        vf);
     REGISTER_FILTER(HFLIP,          hflip,          vf);
     REGISTER_FILTER(HISTEQ,         histeq,         vf);
+    REGISTER_FILTER(HISTOGRAM,      histogram,      vf);
     REGISTER_FILTER(HQDN3D,         hqdn3d,         vf);
     REGISTER_FILTER(HUE,            hue,            vf);
     REGISTER_FILTER(IDET,           idet,           vf);
diff --git a/libavfilter/vf_histogram.c b/libavfilter/vf_histogram.c
new file mode 100644
index 0000000..13dc892
--- /dev/null
+++ b/libavfilter/vf_histogram.c
@@ -0,0 +1,313 @@
+/*
+ * Copyright (c) 2012 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/opt.h"
+#include "libavutil/parseutils.h"
+#include "libavutil/pixdesc.h"
+#include "avfilter.h"
+#include "formats.h"
+#include "drawutils.h"
+#include "internal.h"
+#include "video.h"
+
+enum histogram_mode {
+    HISTOGRAM,
+    SCOPE,
+    MODE_NB
+};
+
+typedef struct HistogramContext {
+    const AVClass *class;               ///< AVClass context for log and options purpose
+    int            mode;
+    unsigned       histogram[1 << 16];
+    unsigned       histogram_size;
+    unsigned       max_hval;
+    int            comp_yuv[4], comp_rgb[4];
+    uint8_t        rgba_map[4];
+    int            is_packed_rgb;
+    int            ncomp;
+    int            do_graph;
+    int            w, h;
+    FFDrawContext  draw;
+    FFDrawColor    bg, fg;
+    char          *fg_color_str, *bg_color_str;
+    uint8_t        fg_color_rgba[4], bg_color_rgba[4];
+} HistogramContext;
+
+#define Y 0
+#define U 1
+#define V 2
+#define R 0
+#define G 1
+#define B 2
+#define A 3
+
+#define OFFSET(x) offsetof(HistogramContext, x)
+#define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
+
+static const AVOption histogram_options[] = {
+    { "mode", "set histogram mode", OFFSET(mode), AV_OPT_TYPE_INT, {.i64=HISTOGRAM}, 0, MODE_NB-1, FLAGS, "mode"},
+    { "histogram", "standard histogram", 0, AV_OPT_TYPE_CONST, {.i64=HISTOGRAM}, 0, 0, FLAGS, "mode" },
+    { "scope", "scope", 0, AV_OPT_TYPE_CONST, {.i64=SCOPE}, 0, 0, FLAGS, "mode" },
+    { "graph", "show histogram graph", OFFSET(do_graph), AV_OPT_TYPE_INT, {.i64=1}, 0, 1, FLAGS},
+    { "size", "set histogram graph video size", OFFSET(w), AV_OPT_TYPE_IMAGE_SIZE, {.str = "256x256"}, 0, 0, FLAGS },
+    { "fg", "set histogram foreground color", OFFSET(fg_color_str), AV_OPT_TYPE_STRING, {.str = "white"}, CHAR_MIN, CHAR_MAX, FLAGS },
+    { "bg", "set histogram background color", OFFSET(bg_color_str), AV_OPT_TYPE_STRING, {.str = "black"}, CHAR_MIN, CHAR_MAX, FLAGS },
+    { "y", "use Y component", OFFSET(comp_yuv[Y]), AV_OPT_TYPE_INT, {.i64=1}, 0, 1, FLAGS},
+    { "u", "use U component", OFFSET(comp_yuv[U]), AV_OPT_TYPE_INT, {.i64=0}, 0, 1, FLAGS},
+    { "v", "use V component", OFFSET(comp_yuv[V]), AV_OPT_TYPE_INT, {.i64=0}, 0, 1, FLAGS},
+    { "a", "use A component", OFFSET(comp_yuv[A]), AV_OPT_TYPE_INT, {.i64=0}, 0, 1, FLAGS},
+    { "r", "use R component", OFFSET(comp_rgb[R]), AV_OPT_TYPE_INT, {.i64=1}, 0, 1, FLAGS},
+    { "g", "use G component", OFFSET(comp_rgb[G]), AV_OPT_TYPE_INT, {.i64=1}, 0, 1, FLAGS},
+    { "b", "use B component", OFFSET(comp_rgb[B]), AV_OPT_TYPE_INT, {.i64=1}, 0, 1, FLAGS},
+    { NULL },
+};
+
+AVFILTER_DEFINE_CLASS(histogram);
+
+static av_cold int init(AVFilterContext *ctx, const char *args)
+{
+    HistogramContext *h = ctx->priv;
+    int ret;
+
+    h->class = &histogram_class;
+    av_opt_set_defaults(h);
+
+    if ((ret = (av_set_options_string(h, args, "=", ":"))) < 0)
+        return ret;
+
+    if (h->h < 256 || h->w < 256)
+        return AVERROR(EINVAL);
+
+    if ((ret = av_parse_color(h->fg_color_rgba, h->fg_color_str, -1, ctx)) < 0 ||
+        (ret = av_parse_color(h->bg_color_rgba, h->bg_color_str, -1, ctx)) < 0 )
+        return ret;
+
+    h->comp_rgb[A] = h->comp_yuv[A];
+    if (!h->comp_rgb[R] && !h->comp_rgb[G] && !h->comp_rgb[B] && !h->comp_rgb[A] &&
+        !h->comp_yuv[Y] && !h->comp_yuv[U] && !h->comp_yuv[V] && !h->comp_yuv[A])
+        return AVERROR(EINVAL);
+
+    return 0;
+}
+
+static int query_formats(AVFilterContext *ctx)
+{
+    static const enum AVPixelFormat pix_fmts[] = {
+        AV_PIX_FMT_YUV444P, AV_PIX_FMT_YUVA444P, AV_PIX_FMT_YUVJ444P,
+        AV_PIX_FMT_BGR24, AV_PIX_FMT_RGB24,
+        AV_PIX_FMT_ABGR, AV_PIX_FMT_0BGR,
+        AV_PIX_FMT_ARGB, AV_PIX_FMT_0RGB,
+        AV_PIX_FMT_BGRA, AV_PIX_FMT_BGR0,
+        AV_PIX_FMT_RGBA, AV_PIX_FMT_RGB0,
+        AV_PIX_FMT_GRAY8, AV_PIX_FMT_GRAY8A,
+        AV_PIX_FMT_NONE
+    };
+
+    ff_set_common_formats(ctx, ff_make_format_list(pix_fmts));
+
+    return 0;
+}
+
+static int config_input(AVFilterLink *inlink)
+{
+    HistogramContext *h = inlink->dst->priv;
+    const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
+
+    h->histogram_size = 1 << desc->comp[0].depth_minus1 + 1;
+    h->ncomp          = desc->nb_components;
+    h->is_packed_rgb  = ff_fill_rgba_map(h->rgba_map, inlink->format) >= 0;
+
+    return 0;
+}
+
+static int config_output(AVFilterLink *outlink)
+{
+    AVFilterContext *ctx = outlink->src;
+    HistogramContext *h = ctx->priv;
+
+    if (!h->do_graph)
+        return 0;
+
+    outlink->w = h->w;
+    outlink->h = h->h;
+
+    outlink->sample_aspect_ratio = (AVRational){1,1};
+
+    ff_draw_init(&h->draw, outlink->format, 0);
+    ff_draw_color(&h->draw, &h->bg, h->bg_color_rgba);
+    ff_draw_color(&h->draw, &h->fg, h->fg_color_rgba);
+
+    return 0;
+}
+
+static int filter_frame(AVFilterLink *inlink, AVFilterBufferRef *in)
+{
+    HistogramContext *h   = inlink->dst->priv;
+    AVFilterContext *ctx  = inlink->dst;
+    AVFilterLink *outlink = ctx->outputs[0];
+    const uint8_t *src;
+    int i, j, k, ret;
+
+    if (h->is_packed_rgb) {
+        src = in->data[0];
+        for (i = 0; i < in->video->h; i++) {
+            for (j = 0; j < in->video->w * h->ncomp; j += h->ncomp) {
+                unsigned v = 0, used = 0;
+
+                for (k = 0; k < h->ncomp; k++) {
+                    if (h->comp_rgb[k]) {
+                        v += src[j + h->rgba_map[k]];
+                        used++;
+                    }
+                }
+
+                if (used)
+                    h->histogram[v / used]++;
+            }
+            src += in->linesize[0];
+        }
+    } else {
+        for (i = 0; i < in->video->h; i++) {
+            for (j = 0; j < in->video->w; j++) {
+                unsigned v = 0, used = 0;
+
+                for (k = 0; k < h->ncomp; k++) {
+                    if (h->comp_yuv[k]) {
+                        src = in->data[k] + i * in->linesize[k];
+                        v += src[j];
+                        used++;
+                    }
+                }
+
+                if (used)
+                    h->histogram[v / used]++;
+            }
+        }
+    }
+
+    for (i = 0; i < h->histogram_size; i++) {
+        h->max_hval = FFMAX(h->max_hval, h->histogram[i]);
+        if (h->histogram[i])
+            av_log(ctx, h->do_graph ? AV_LOG_VERBOSE : AV_LOG_INFO, "i:%d c:%d\n", i, h->histogram[i]);
+    }
+
+    if (h->do_graph) {
+        AVFilterBufferRef *outpicref;
+        int col_width = h->w / h->histogram_size;
+
+        outpicref = ff_get_video_buffer(outlink, AV_PERM_WRITE, outlink->w, outlink->h);
+        if (!outpicref) {
+            avfilter_unref_bufferp(&in);
+            return AVERROR(ENOMEM);
+        }
+
+        outpicref->pts = in->pts;
+        outpicref->pos = in->pos;
+
+        ff_fill_rectangle(&h->draw, &h->bg, outpicref->data, outpicref->linesize, 0, 0, h->w, h->h);
+        if (h->mode == HISTOGRAM) {
+            for (i = 0; i < h->histogram_size; i++) {
+                int col_height = (float) h->histogram[i] / h->max_hval * h->h;
+
+                ff_fill_rectangle(&h->draw, &h->fg,
+                                  outpicref->data, outpicref->linesize,
+                                  i * col_width, h->h - col_height,
+                                  col_width, col_height);
+            }
+        } else {
+            if (!h->is_packed_rgb) {
+                for (i = 0; i < in->video->w; i++) {
+                    for (j = 0; j < in->video->h; j++) {
+                        for (k = 0; k < h->ncomp; k++) {
+                            if (h->comp_yuv[k]) {
+                                if (outpicref->data[k][((h->h - 1) - in->data[k][j * in->video->w + i]) * h->w + i] < 255)
+                                    outpicref->data[k][((h->h - 1) - in->data[k][j * in->video->w + i]) * h->w + i] += 2;
+                            }
+                        }
+                    }
+                }
+            } else {
+                for (i = 0; i < in->video->w; i++) {
+                    for (j = 0; j < in->video->h; j++) {
+                        for (k = 0; k < h->ncomp; k++) {
+                            if (h->comp_rgb[k]) {
+                                if (outpicref->data[0][((h->h - 1) * h->ncomp - in->data[0][j * in->video->w * h->ncomp + i * h->ncomp] + k) * h->w + i * h->ncomp + k] < 255)
+                                    outpicref->data[0][((h->h - 1) * h->ncomp - in->data[0][j * in->video->w * h->ncomp + i * h->ncomp] + k) * h->w + i * h->ncomp + k] += 2;
+                            }
+                        }
+                    }
+                }
+            }
+        }
+
+        ret = ff_filter_frame(outlink, outpicref);
+        avfilter_unref_bufferp(&in);
+        if (ret < 0)
+            return ret;
+    } else {
+        ret = ff_filter_frame(outlink, in);
+        if (ret < 0)
+            return ret;
+    }
+    memset(h->histogram, 0, h->histogram_size * sizeof(*h->histogram));
+    h->max_hval = 0;
+
+    return 0;
+}
+
+static av_cold void uninit(AVFilterContext *ctx)
+{
+    HistogramContext *h = ctx->priv;
+
+    av_opt_free(h);
+}
+
+static const AVFilterPad histogram_inputs[] = {
+    {
+        .name         = "default",
+        .type         = AVMEDIA_TYPE_VIDEO,
+        .filter_frame = filter_frame,
+        .config_props = config_input,
+        .min_perms    = AV_PERM_READ,
+    },
+    { NULL }
+};
+
+static const AVFilterPad histogram_outputs[] = {
+    {
+        .name         = "default",
+        .type         = AVMEDIA_TYPE_VIDEO,
+        .config_props = config_output,
+    },
+    { NULL }
+};
+
+AVFilter avfilter_vf_histogram = {
+    .name          = "histogram",
+    .description   = NULL_IF_CONFIG_SMALL("Compute and draw an histogram."),
+    .priv_size     = sizeof(HistogramContext),
+    .init          = init,
+    .uninit        = uninit,
+    .query_formats = query_formats,
+    .inputs        = histogram_inputs,
+    .outputs       = histogram_outputs,
+    .priv_class    = &histogram_class,
+};
-- 
1.7.11.4



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