[FFmpeg-devel] avfilter: add deflicker filter

diff --git a/doc/filters.texi b/doc/filters.texi
index e002f25..83b8111 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -6253,6 +6253,44 @@  Limit the maximum change for each plane, default is 65535.
 If 0, plane will remain unchanged.
 @end table
 
+@section deflicker
+
+Remove temporal frame luminance variations.
+
+It accepts the following options:
+
+@table @option
+@item size, s
+Set moving-average filter size. Default is 5. Allowed range is 2 - 129.
+
+@item mode, m
+Set averaging mode to smooth temporal luminance variations.
+
+Available values are:
+@table @samp
+@item am
+Arithmetic mean
+
+@item gm
+Geometric mean
+
+@item hm
+Harmonic mean
+
+@item qm
+Quadratic mean
+
+@item cm
+Cubic mean
+
+@item pm
+Power mean
+
+@item median
+Median
+@end table
+@end table
+
 @section dejudder
 
 Remove judder produced by partially interlaced telecined content.
diff --git a/libavfilter/Makefile b/libavfilter/Makefile
index d6daa7a..6de7cc0 100644
--- a/libavfilter/Makefile
+++ b/libavfilter/Makefile
@@ -155,6 +155,7 @@  OBJS-$(CONFIG_DCTDNOIZ_FILTER)               += vf_dctdnoiz.o
 OBJS-$(CONFIG_DEBAND_FILTER)                 += vf_deband.o
 OBJS-$(CONFIG_DECIMATE_FILTER)               += vf_decimate.o
 OBJS-$(CONFIG_DEFLATE_FILTER)                += vf_neighbor.o
+OBJS-$(CONFIG_DEFLICKER_FILTER)              += vf_deflicker.o
 OBJS-$(CONFIG_DEINTERLACE_QSV_FILTER)        += vf_deinterlace_qsv.o
 OBJS-$(CONFIG_DEINTERLACE_VAAPI_FILTER)      += vf_deinterlace_vaapi.o
 OBJS-$(CONFIG_DEJUDDER_FILTER)               += vf_dejudder.o
diff --git a/libavfilter/allfilters.c b/libavfilter/allfilters.c
index ec6ec04..0e69f99 100644
--- a/libavfilter/allfilters.c
+++ b/libavfilter/allfilters.c
@@ -166,6 +166,7 @@  static void register_all(void)
     REGISTER_FILTER(DEBAND,         deband,         vf);
     REGISTER_FILTER(DECIMATE,       decimate,       vf);
     REGISTER_FILTER(DEFLATE,        deflate,        vf);
+    REGISTER_FILTER(DEFLICKER,      deflicker,      vf);
     REGISTER_FILTER(DEINTERLACE_QSV,deinterlace_qsv,vf);
     REGISTER_FILTER(DEINTERLACE_VAAPI, deinterlace_vaapi, vf);
     REGISTER_FILTER(DEJUDDER,       dejudder,       vf);
diff --git a/libavfilter/vf_deflicker.c b/libavfilter/vf_deflicker.c
new file mode 100644
index 0000000..bf0c847
--- /dev/null
+++ b/libavfilter/vf_deflicker.c
@@ -0,0 +1,455 @@ 
+/*
+ * Copyright (c) 2017 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/opt.h"
+#include "libavutil/pixdesc.h"
+#include "libavutil/qsort.h"
+#include "avfilter.h"
+
+#define FF_BUFQUEUE_SIZE 129
+#include "bufferqueue.h"
+
+#include "formats.h"
+#include "internal.h"
+#include "video.h"
+
+#define SIZE FF_BUFQUEUE_SIZE
+
+enum smooth_mode {
+    ARITHMETIC_MEAN,
+    GEOMETRIC_MEAN,
+    HARMONIC_MEAN,
+    QUADRATIC_MEAN,
+    CUBIC_MEAN,
+    POWER_MEAN,
+    MEDIAN,
+    NB_SMOOTH_MODE,
+};
+
+typedef struct DeflickerContext {
+    const AVClass *class;
+
+    int size;
+    int mode;
+
+    int eof;
+    int depth;
+    int nb_planes;
+    int planewidth[4];
+    int planeheight[4];
+
+    uint64_t *histogram;
+    float luminance[SIZE];
+    float sorted[SIZE];
+
+    struct FFBufQueue q;
+    int available;
+
+    void (*get_factor)(AVFilterContext *ctx, float *f);
+    float (*calc_avgy)(AVFilterContext *ctx, AVFrame *in);
+    int (*deflicker)(AVFilterContext *ctx, AVFrame *in, AVFrame *out, float f);
+} DeflickerContext;
+
+#define OFFSET(x) offsetof(DeflickerContext, x)
+#define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
+
+static const AVOption deflicker_options[] = {
+    { "size",  "set how many frames to use", OFFSET(size), AV_OPT_TYPE_INT, {.i64=5}, 2, SIZE, FLAGS },
+    { "s",     "set how many frames to use", OFFSET(size), AV_OPT_TYPE_INT, {.i64=5}, 2, SIZE, FLAGS },
+    { "mode",  "set how to smooth luminance", OFFSET(mode), AV_OPT_TYPE_INT, {.i64=0}, 0, 1, FLAGS, "mode" },
+    { "m",     "set how to smooth luminance", OFFSET(mode), AV_OPT_TYPE_INT, {.i64=0}, 0, NB_SMOOTH_MODE-1, FLAGS, "mode" },
+        { "am",      "arithmetic mean", 0, AV_OPT_TYPE_CONST, {.i64=ARITHMETIC_MEAN},  0, 0, FLAGS, "mode" },
+        { "gm",      "geometric mean",  0, AV_OPT_TYPE_CONST, {.i64=GEOMETRIC_MEAN},   0, 0, FLAGS, "mode" },
+        { "hm",      "harmonic mean",   0, AV_OPT_TYPE_CONST, {.i64=HARMONIC_MEAN},    0, 0, FLAGS, "mode" },
+        { "qm",      "quadratic mean",  0, AV_OPT_TYPE_CONST, {.i64=QUADRATIC_MEAN},   0, 0, FLAGS, "mode" },
+        { "cm",      "cubic mean",      0, AV_OPT_TYPE_CONST, {.i64=CUBIC_MEAN},       0, 0, FLAGS, "mode" },
+        { "pm",      "power mean",      0, AV_OPT_TYPE_CONST, {.i64=POWER_MEAN},       0, 0, FLAGS, "mode" },
+        { "median",  "median",          0, AV_OPT_TYPE_CONST, {.i64=MEDIAN},           0, 0, FLAGS, "mode" },
+    { NULL }
+};
+
+AVFILTER_DEFINE_CLASS(deflicker);
+
+static int query_formats(AVFilterContext *ctx)
+{
+    static const enum AVPixelFormat pixel_fmts[] = {
+        AV_PIX_FMT_GRAY8, AV_PIX_FMT_GRAY10,
+        AV_PIX_FMT_GRAY12, AV_PIX_FMT_GRAY16,
+        AV_PIX_FMT_YUV410P, AV_PIX_FMT_YUV411P,
+        AV_PIX_FMT_YUV420P, AV_PIX_FMT_YUV422P,
+        AV_PIX_FMT_YUV440P, AV_PIX_FMT_YUV444P,
+        AV_PIX_FMT_YUVJ420P, AV_PIX_FMT_YUVJ422P,
+        AV_PIX_FMT_YUVJ440P, AV_PIX_FMT_YUVJ444P,
+        AV_PIX_FMT_YUVJ411P,
+        AV_PIX_FMT_YUV420P9, AV_PIX_FMT_YUV422P9, AV_PIX_FMT_YUV444P9,
+        AV_PIX_FMT_YUV420P10, AV_PIX_FMT_YUV422P10, AV_PIX_FMT_YUV444P10,
+        AV_PIX_FMT_YUV440P10,
+        AV_PIX_FMT_YUV444P12, AV_PIX_FMT_YUV422P12, AV_PIX_FMT_YUV420P12,
+        AV_PIX_FMT_YUV440P12,
+        AV_PIX_FMT_YUV444P14, AV_PIX_FMT_YUV422P14, AV_PIX_FMT_YUV420P14,
+        AV_PIX_FMT_YUV420P16, AV_PIX_FMT_YUV422P16, AV_PIX_FMT_YUV444P16,
+        AV_PIX_FMT_NONE
+    };
+    AVFilterFormats *formats = ff_make_format_list(pixel_fmts);
+    if (!formats)
+        return AVERROR(ENOMEM);
+    return ff_set_common_formats(ctx, formats);
+}
+
+static int deflicker8(AVFilterContext *ctx, AVFrame *in, AVFrame *out, float f)
+{
+    DeflickerContext *s = ctx->priv;
+    const int h = s->planeheight[0];
+    const int w = s->planewidth[0];
+    const uint8_t *src = in->data[0];
+    uint8_t *dst = out->data[0];
+    const int max = (1 << s->depth) - 1;
+    int x, y;
+
+    for (y = 0; y < h; y++) {
+        for (x = 0; x < w; x++) {
+            dst[x] = av_clip(src[x] * f, 0, max);
+        }
+
+        dst += out->linesize[0];
+        src += in->linesize[0];
+    }
+
+    return 0;
+}
+
+static int deflicker16(AVFilterContext *ctx, AVFrame *in, AVFrame *out, float f)
+{
+    DeflickerContext *s = ctx->priv;
+    const int h = s->planeheight[0];
+    const int w = s->planewidth[0];
+    const uint16_t *src = (const uint16_t *)in->data[0];
+    uint16_t *dst = (uint16_t *)out->data[0];
+    const int max = (1 << s->depth) - 1;
+    int x, y;
+
+    for (y = 0; y < h; y++) {
+        for (x = 0; x < w; x++) {
+            dst[x] = av_clip(src[x] * f, 0, max);
+        }
+
+        dst += out->linesize[0] / 2;
+        src += in->linesize[0] / 2;
+    }
+
+    return 0;
+}
+
+static float calc_avgy8(AVFilterContext *ctx, AVFrame *in)
+{
+    DeflickerContext *s = ctx->priv;
+    const uint8_t *src = in->data[0];
+    int64_t sum = 0;
+    int y, x;
+
+    memset(s->histogram, 0, (1 << s->depth) * sizeof(*s->histogram));
+
+    for (y = 0; y < s->planeheight[0]; y++) {
+        for (x = 0; x < s->planewidth[0]; x++) {
+            s->histogram[src[x]]++;
+        }
+        src += in->linesize[0];
+    }
+
+    for (y = 0; y < 1 << s->depth; y++) {
+        sum += s->histogram[y] * y;
+    }
+
+    return 1.0 * sum / (s->planeheight[0] * s->planewidth[0]);
+}
+
+static float calc_avgy16(AVFilterContext *ctx, AVFrame *in)
+{
+    DeflickerContext *s = ctx->priv;
+    const uint16_t *src = (const uint16_t *)in->data[0];
+    int64_t sum = 0;
+    int y, x;
+
+    memset(s->histogram, 0, (1 << s->depth) * sizeof(*s->histogram));
+
+    for (y = 0; y < s->planeheight[0]; y++) {
+        for (x = 0; x < s->planewidth[0]; x++) {
+            s->histogram[src[x]]++;
+        }
+        src += in->linesize[0] / 2;
+    }
+
+    for (y = 0; y < 1 << s->depth; y++) {
+        sum += s->histogram[y] * y;
+    }
+
+    return 1.0 * sum / (s->planeheight[0] * s->planewidth[0]);
+}
+
+static void get_am_factor(AVFilterContext *ctx, float *f)
+{
+    DeflickerContext *s = ctx->priv;
+    int y;
+
+    *f = 0;
+
+    for (y = 0; y < s->size; y++) {
+        *f += s->luminance[y];
+    }
+
+    *f /= s->size;
+    *f /= s->luminance[0];
+}
+
+static void get_gm_factor(AVFilterContext *ctx, float *f)
+{
+    DeflickerContext *s = ctx->priv;
+    int y;
+
+    *f = 1;
+
+    for (y = 0; y < s->size; y++) {
+        *f *= s->luminance[y];
+    }
+
+    *f = pow(*f, 1./s->size);
+    *f /= s->luminance[0];
+}
+
+static void get_hm_factor(AVFilterContext *ctx, float *f)
+{
+    DeflickerContext *s = ctx->priv;
+    int y;
+
+    *f = 0;
+
+    for (y = 0; y < s->size; y++) {
+        *f += 1./s->luminance[y];
+    }
+
+    *f = s->size / *f;
+    *f /= s->luminance[0];
+}
+
+static void get_qm_factor(AVFilterContext *ctx, float *f)
+{
+    DeflickerContext *s = ctx->priv;
+    int y;
+
+    *f = 0;
+
+    for (y = 0; y < s->size; y++) {
+        *f += s->luminance[y] * s->luminance[y];
+    }
+
+    *f /= s->size;
+    *f  = sqrt(*f);
+    *f /= s->luminance[0];
+}
+
+static void get_cm_factor(AVFilterContext *ctx, float *f)
+{
+    DeflickerContext *s = ctx->priv;
+    int y;
+
+    *f = 0;
+
+    for (y = 0; y < s->size; y++) {
+        *f += s->luminance[y] * s->luminance[y] * s->luminance[y];
+    }
+
+    *f /= s->size;
+    *f  = cbrt(*f);
+    *f /= s->luminance[0];
+}
+
+static void get_pm_factor(AVFilterContext *ctx, float *f)
+{
+    DeflickerContext *s = ctx->priv;
+    int y;
+
+    *f = 0;
+
+    for (y = 0; y < s->size; y++) {
+        *f += pow(s->luminance[y], s->size);
+    }
+
+    *f /= s->size;
+    *f  = pow(*f, 1./s->size);
+    *f /= s->luminance[0];
+}
+
+static int comparef(const void *a, const void *b)
+{
+    const float *aa = a, *bb = b;
+    return round(aa - bb);
+}
+
+static void get_median_factor(AVFilterContext *ctx, float *f)
+{
+    DeflickerContext *s = ctx->priv;
+
+    memcpy(s->sorted, s->luminance, sizeof(s->sorted));
+    AV_QSORT(s->sorted, s->size, float, comparef);
+
+    *f = s->sorted[s->size >> 1] / s->luminance[0];
+}
+
+static int config_input(AVFilterLink *inlink)
+{
+    const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
+    AVFilterContext *ctx = inlink->dst;
+    DeflickerContext *s = ctx->priv;
+
+    s->nb_planes = desc->nb_components;
+
+    s->planeheight[1] = s->planeheight[2] = AV_CEIL_RSHIFT(inlink->h, desc->log2_chroma_h);
+    s->planeheight[0] = s->planeheight[3] = inlink->h;
+    s->planewidth[1]  = s->planewidth[2]  = AV_CEIL_RSHIFT(inlink->w, desc->log2_chroma_w);
+    s->planewidth[0]  = s->planewidth[3]  = inlink->w;
+
+    s->depth = desc->comp[0].depth;
+    if (s->depth == 8) {
+        s->deflicker = deflicker8;
+        s->calc_avgy = calc_avgy8;
+    } else {
+        s->deflicker = deflicker16;
+        s->calc_avgy = calc_avgy16;
+    }
+
+    s->histogram = av_calloc(1 << s->depth, sizeof(*s->histogram));
+    if (!s->histogram)
+        return AVERROR(ENOMEM);
+
+    switch (s->mode) {
+    case MEDIAN:          s->get_factor = get_median_factor; break;
+    case ARITHMETIC_MEAN: s->get_factor = get_am_factor;     break;
+    case GEOMETRIC_MEAN:  s->get_factor = get_gm_factor;     break;
+    case HARMONIC_MEAN:   s->get_factor = get_hm_factor;     break;
+    case QUADRATIC_MEAN:  s->get_factor = get_qm_factor;     break;
+    case CUBIC_MEAN:      s->get_factor = get_cm_factor;     break;
+    case POWER_MEAN:      s->get_factor = get_pm_factor;     break;
+    }
+
+    return 0;
+}
+
+static int filter_frame(AVFilterLink *inlink, AVFrame *buf)
+{
+    AVFilterContext *ctx = inlink->dst;
+    AVFilterLink *outlink = ctx->outputs[0];
+    DeflickerContext *s = ctx->priv;
+    AVFrame *out, *in;
+    float f;
+    int y;
+
+    if (s->q.available < s->size && !s->eof) {
+        s->luminance[s->available] = s->calc_avgy(ctx, buf);
+        ff_bufqueue_add(ctx, &s->q, buf);
+        s->available++;
+        return 0;
+    }
+
+    in = ff_bufqueue_peek(&s->q, 0);
+
+    out = ff_get_video_buffer(outlink, outlink->w, outlink->h);
+    if (!out) {
+        av_frame_free(&buf);
+        return AVERROR(ENOMEM);
+    }
+
+    s->get_factor(ctx, &f);
+    s->deflicker(ctx, in, out, f);
+    for (y = 1; y < s->nb_planes; y++) {
+        av_image_copy_plane(out->data[y], out->linesize[y],
+                            in->data[y], in->linesize[y],
+                            s->planewidth[y] * (1 + (s->depth > 8)), s->planeheight[y]);
+    }
+
+    av_frame_copy_props(out, in);
+
+    in = ff_bufqueue_get(&s->q);
+    av_frame_free(&in);
+    memmove(&s->luminance[0], &s->luminance[1], sizeof(*s->luminance) * (s->size - 1));
+    s->luminance[s->available - 1] = s->calc_avgy(ctx, buf);
+    ff_bufqueue_add(ctx, &s->q, buf);
+
+    return ff_filter_frame(outlink, out);
+}
+
+static int request_frame(AVFilterLink *outlink)
+{
+    AVFilterContext *ctx = outlink->src;
+    DeflickerContext *s = ctx->priv;
+    int ret;
+
+    ret = ff_request_frame(ctx->inputs[0]);
+    if (ret == AVERROR_EOF && s->available > 0) {
+        AVFrame *buf = av_frame_clone(ff_bufqueue_peek(&s->q, s->size - 1));
+        if (!buf)
+            return AVERROR(ENOMEM);
+
+        s->eof = 1;
+        ret = filter_frame(ctx->inputs[0], buf);
+        s->available--;
+    }
+
+
+    return ret;
+}
+
+static av_cold void uninit(AVFilterContext *ctx)
+{
+    DeflickerContext *s = ctx->priv;
+
+    ff_bufqueue_discard_all(&s->q);
+    av_freep(&s->histogram);
+}
+
+static const AVFilterPad inputs[] = {
+    {
+        .name         = "default",
+        .type         = AVMEDIA_TYPE_VIDEO,
+        .filter_frame = filter_frame,
+        .config_props = config_input,
+    },
+    { NULL }
+};
+
+static const AVFilterPad outputs[] = {
+    {
+        .name          = "default",
+        .type          = AVMEDIA_TYPE_VIDEO,
+        .request_frame = request_frame,
+    },
+    { NULL }
+};
+
+AVFilter ff_vf_deflicker = {
+    .name          = "deflicker",
+    .description   = NULL_IF_CONFIG_SMALL("Remove temporal frame luminance variations."),
+    .priv_size     = sizeof(DeflickerContext),
+    .priv_class    = &deflicker_class,
+    .uninit        = uninit,
+    .query_formats = query_formats,
+    .inputs        = inputs,
+    .outputs       = outputs,
+};