[FFmpeg-devel] avfilter: add shufflepixels video filter

diff --git a/doc/filters.texi b/doc/filters.texi
index a290239a02..0e61ac32ce 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -17837,6 +17837,33 @@  ffmpeg -i INPUT -vf "shuffleframes=9 1 2 3 4 5 6 7 8 0" OUTPUT
 @end example
 @end itemize
 
+@section shufflepixels
+
+Reorder pixels in video frames.
+
+This filter accepts the following options:
+
+@table @option
+@item direction, d
+Set shuffle direction. Can be forward or inverse direction.
+Default direction is forward.
+
+@item mode, m
+Set shuffle mode. Can be horizontal, vertical or block mode.
+
+@item width, w
+@item height, h
+Set shuffle block_size. In case of horizontal shuffle mode only width
+part of size is used, and in case of vertical shuffle mode only height
+part of size is used.
+
+@item seed, s
+Set random seed used with shuffling pixels. Mainly useful to set to be able
+to reverse filtering process to get original input.
+For example, to reverse forward shuffle you need to use same parameters
+and exact same seed and to set direction to inverse.
+@end table
+
 @section shuffleplanes
 
 Reorder and/or duplicate video planes.
diff --git a/libavfilter/Makefile b/libavfilter/Makefile
index e8db1be5df..b0fb58e9d7 100644
--- a/libavfilter/Makefile
+++ b/libavfilter/Makefile
@@ -408,6 +408,7 @@  OBJS-$(CONFIG_SHARPNESS_VAAPI_FILTER)        += vf_misc_vaapi.o vaapi_vpp.o
 OBJS-$(CONFIG_SHOWINFO_FILTER)               += vf_showinfo.o
 OBJS-$(CONFIG_SHOWPALETTE_FILTER)            += vf_showpalette.o
 OBJS-$(CONFIG_SHUFFLEFRAMES_FILTER)          += vf_shuffleframes.o
+OBJS-$(CONFIG_SHUFFLEPIXELS_FILTER)          += vf_shufflepixels.o
 OBJS-$(CONFIG_SHUFFLEPLANES_FILTER)          += vf_shuffleplanes.o
 OBJS-$(CONFIG_SIDEDATA_FILTER)               += f_sidedata.o
 OBJS-$(CONFIG_SIGNALSTATS_FILTER)            += vf_signalstats.o
diff --git a/libavfilter/allfilters.c b/libavfilter/allfilters.c
index b1413730e6..c4a841b4d6 100644
--- a/libavfilter/allfilters.c
+++ b/libavfilter/allfilters.c
@@ -389,6 +389,7 @@  extern AVFilter ff_vf_sharpness_vaapi;
 extern AVFilter ff_vf_showinfo;
 extern AVFilter ff_vf_showpalette;
 extern AVFilter ff_vf_shuffleframes;
+extern AVFilter ff_vf_shufflepixels;
 extern AVFilter ff_vf_shuffleplanes;
 extern AVFilter ff_vf_sidedata;
 extern AVFilter ff_vf_signalstats;
diff --git a/libavfilter/vf_shufflepixels.c b/libavfilter/vf_shufflepixels.c
new file mode 100644
index 0000000000..463bb66bc8
--- /dev/null
+++ b/libavfilter/vf_shufflepixels.c
@@ -0,0 +1,456 @@ 
+/*
+ * Copyright (c) 2020 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/avassert.h"
+#include "libavutil/avstring.h"
+#include "libavutil/common.h"
+#include "libavutil/internal.h"
+#include "libavutil/imgutils.h"
+#include "libavutil/lfg.h"
+#include "libavutil/opt.h"
+#include "libavutil/pixdesc.h"
+#include "libavutil/random_seed.h"
+
+#include "avfilter.h"
+#include "internal.h"
+#include "video.h"
+
+typedef struct ShufflePixelsContext {
+    const AVClass *class;
+
+    int block_w, block_h;
+    int mode;
+    int direction;
+    int64_t seed;
+
+    int depth;
+    int nb_planes;
+    int linesize[4];
+    int planewidth[4];
+    int planeheight[4];
+
+    int nb_blocks;
+
+    uint8_t *used;
+    int32_t *map;
+
+    AVLFG c;
+
+    int (*shuffle_pixels)(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs);
+} ShufflePixelsContext;
+
+static int query_formats(AVFilterContext *ctx)
+{
+    static const enum AVPixelFormat pix_fmts[] = {
+        AV_PIX_FMT_GRAY8, AV_PIX_FMT_GRAY9, AV_PIX_FMT_GRAY10, AV_PIX_FMT_GRAY14, AV_PIX_FMT_GRAY16,
+        AV_PIX_FMT_YUV444P, AV_PIX_FMT_YUVA444P,
+        AV_PIX_FMT_GBRP, AV_PIX_FMT_GBRP9, AV_PIX_FMT_GBRP10, AV_PIX_FMT_GBRAP10,
+        AV_PIX_FMT_GBRP12, AV_PIX_FMT_GBRAP12, AV_PIX_FMT_GBRP14, AV_PIX_FMT_GBRP16,
+        AV_PIX_FMT_GBRAP16, AV_PIX_FMT_GBRAP,
+        AV_PIX_FMT_YUV444P9, AV_PIX_FMT_YUVA444P9, AV_PIX_FMT_YUV444P10, AV_PIX_FMT_YUVA444P10,
+        AV_PIX_FMT_YUV444P12, AV_PIX_FMT_YUV444P14, AV_PIX_FMT_YUV444P16, AV_PIX_FMT_YUVA444P16,
+        AV_PIX_FMT_NONE
+    };
+    AVFilterFormats *fmts_list = ff_make_format_list(pix_fmts);
+    if (!fmts_list)
+        return AVERROR(ENOMEM);
+    return ff_set_common_formats(ctx, fmts_list);
+}
+
+static void make_horizontal_map(AVFilterContext *ctx)
+{
+    ShufflePixelsContext *s = ctx->priv;
+    const int nb_blocks = s->nb_blocks;
+    AVLFG *c = &s->c;
+    uint8_t *used = s->used;
+    int32_t *map = s->map;
+
+    for (int x = 0; x < s->planewidth[0];) {
+        int rand = av_lfg_get(c) % nb_blocks;
+
+        if (used[rand] == 0) {
+            int width;
+
+            if (s->direction) {
+                width = FFMIN(s->block_w, s->planewidth[0] - x);
+                map[rand * s->block_w] = x;
+            } else {
+                width = FFMIN(s->block_w, s->planewidth[0] - rand * s->block_w);
+                map[x] = rand * s->block_w;
+            }
+            used[rand] = 1;
+
+            if (s->direction) {
+                for (int i = 1; i < width; i++) {
+                    map[rand * s->block_w + i] = map[rand * s->block_w] + i;
+                }
+            } else {
+                for (int i = 1; i < width; i++) {
+                    map[x + i] = map[x] + i;
+                }
+            }
+
+            x += width;
+        }
+    }
+}
+
+static void make_vertical_map(AVFilterContext *ctx)
+{
+    ShufflePixelsContext *s = ctx->priv;
+    const int nb_blocks = s->nb_blocks;
+    AVLFG *c = &s->c;
+    uint8_t *used = s->used;
+    int32_t *map = s->map;
+
+    for (int y = 0; y < s->planeheight[0];) {
+        int rand = av_lfg_get(c) % nb_blocks;
+
+        if (used[rand] == 0) {
+            int height;
+
+            if (s->direction) {
+                height = FFMIN(s->block_h, s->planeheight[0] - y);
+                map[rand * s->block_h] = y;
+            } else {
+                height = FFMIN(s->block_h, s->planeheight[0] - rand * s->block_h);
+                map[y] = rand * s->block_h;
+            }
+            used[rand] = 1;
+
+            if (s->direction) {
+                for (int i = 1; i < height; i++) {
+                    map[rand * s->block_h + i] = map[rand * s->block_h] + i;
+                }
+            } else {
+                for (int i = 1; i < height; i++) {
+                    map[y + i] = map[y] + i;
+                }
+            }
+
+            y += height;
+        }
+    }
+}
+
+static void make_block_map(AVFilterContext *ctx)
+{
+    ShufflePixelsContext *s = ctx->priv;
+    const int nb_blocks = s->nb_blocks;
+    int nb_blocks_w = s->planewidth[0]  / s->block_w;
+    AVLFG *c = &s->c;
+    uint8_t *used = s->used;
+    int32_t *map = s->map;
+
+    for (int i = 0; i < nb_blocks;) {
+        int rand = av_lfg_get(c) % nb_blocks;
+
+        if (used[rand] == 0) {
+            int yin = i / nb_blocks_w;
+            int xin = i % nb_blocks_w;
+            int in = yin * s->block_h * s->planewidth[0] + xin * s->block_w;
+            int yout = rand / nb_blocks_w;
+            int xout = rand % nb_blocks_w;
+            int out = yout * s->block_h * s->planewidth[0] + xout * s->block_w;
+
+            if (s->direction) {
+                map[out] = in;
+            } else {
+                map[in] = out;
+            }
+            used[rand] = 1;
+
+            if (s->direction) {
+                for (int y = 0; y < s->block_h; y++) {
+                    for (int x = 0; x < s->block_w; x++) {
+                        map[out + y * s->planewidth[0] + x] = map[out] + x + y * s->planewidth[0];
+                    }
+                }
+            } else {
+                for (int y = 0; y < s->block_h; y++) {
+                    for (int x = 0; x < s->block_w; x++) {
+                        map[in + y * s->planewidth[0] + x] = map[in] + x + y * s->planewidth[0];
+                    }
+                }
+            }
+
+            i++;
+        }
+    }
+}
+
+typedef struct ThreadData {
+    AVFrame *in, *out;
+} ThreadData;
+
+
+#define SHUFFLE_HORIZONTAL(name, type)                                       \
+static int shuffle_horizontal## name(AVFilterContext *ctx, void *arg,        \
+                                     int jobnr, int nb_jobs)                 \
+{                                                                            \
+    ShufflePixelsContext *s = ctx->priv;                                     \
+    ThreadData *td = arg;                                                    \
+    AVFrame *in = td->in;                                                    \
+    AVFrame *out = td->out;                                                  \
+                                                                             \
+    for (int p = 0; p < s->nb_planes; p++) {                                 \
+        const int slice_start = (s->planeheight[p] * jobnr) / nb_jobs;       \
+        const int slice_end = (s->planeheight[p] * (jobnr+1)) / nb_jobs;     \
+        type *dst = (type *)(out->data[p] + slice_start * out->linesize[p]); \
+        const type *src = (const type *)(in->data[p] +                       \
+                                         slice_start * in->linesize[p]);     \
+        const int32_t *map = s->map;                                         \
+                                                                             \
+        for (int y = slice_start; y < slice_end; y++) {                      \
+            for (int x = 0; x < s->planewidth[p]; x++) {                     \
+                dst[x] = src[map[x]];                                        \
+            }                                                                \
+                                                                             \
+            dst += out->linesize[p] / sizeof(type);                          \
+            src += in->linesize[p] / sizeof(type);                           \
+        }                                                                    \
+    }                                                                        \
+                                                                             \
+    return 0;                                                                \
+}
+
+SHUFFLE_HORIZONTAL(8, uint8_t)
+SHUFFLE_HORIZONTAL(16, uint16_t)
+
+#define SHUFFLE_VERTICAL(name, type)                                         \
+static int shuffle_vertical## name(AVFilterContext *ctx, void *arg,          \
+                            int jobnr, int nb_jobs)                          \
+{                                                                            \
+    ShufflePixelsContext *s = ctx->priv;                                     \
+    ThreadData *td = arg;                                                    \
+    AVFrame *in = td->in;                                                    \
+    AVFrame *out = td->out;                                                  \
+                                                                             \
+    for (int p = 0; p < s->nb_planes; p++) {                                 \
+        const int slice_start = (s->planeheight[p] * jobnr) / nb_jobs;       \
+        const int slice_end = (s->planeheight[p] * (jobnr+1)) / nb_jobs;     \
+        type *dst = (type *)(out->data[p] + slice_start * out->linesize[p]); \
+        const int32_t *map = s->map;                                         \
+                                                                             \
+        for (int y = slice_start; y < slice_end; y++) {                      \
+            const type *src = (const type *)(in->data[p] +                   \
+                                             map[y] * in->linesize[p]);      \
+                                                                             \
+            memcpy(dst, src, s->linesize[p]);                                \
+            dst += out->linesize[p] / sizeof(type);                          \
+        }                                                                    \
+    }                                                                        \
+                                                                             \
+    return 0;                                                                \
+}
+
+SHUFFLE_VERTICAL(8, uint8_t)
+SHUFFLE_VERTICAL(16, uint16_t)
+
+#define SHUFFLE_BLOCK(name, type)                                            \
+static int shuffle_block## name(AVFilterContext *ctx, void *arg,             \
+                         int jobnr, int nb_jobs)                             \
+{                                                                            \
+    ShufflePixelsContext *s = ctx->priv;                                     \
+    ThreadData *td = arg;                                                    \
+    AVFrame *in = td->in;                                                    \
+    AVFrame *out = td->out;                                                  \
+                                                                             \
+    for (int p = 0; p < s->nb_planes; p++) {                                 \
+        const int slice_start = (s->planeheight[p] * jobnr) / nb_jobs;       \
+        const int slice_end = (s->planeheight[p] * (jobnr+1)) / nb_jobs;     \
+        type *dst = (type *)(out->data[p] + slice_start * out->linesize[p]); \
+        const type *src = (const type *)in->data[p];                         \
+        const int32_t *map = s->map + slice_start * s->planewidth[p];        \
+                                                                             \
+        for (int y = slice_start; y < slice_end; y++) {                      \
+            for (int x = 0; x < s->planewidth[p]; x++) {                     \
+                int ymap = map[x] / s->planewidth[p];                        \
+                int xmap = map[x] % s->planewidth[p];                        \
+                                                                             \
+                dst[x] = src[xmap + ymap * in->linesize[p] / sizeof(type)];  \
+            }                                                                \
+                                                                             \
+            dst += out->linesize[p] / sizeof(type);                          \
+            map += s->planewidth[p];                                         \
+        }                                                                    \
+    }                                                                        \
+                                                                             \
+    return 0;                                                                \
+}
+
+SHUFFLE_BLOCK(8, uint8_t)
+SHUFFLE_BLOCK(16, uint16_t)
+
+static int config_output(AVFilterLink *outlink)
+{
+    AVFilterContext *ctx = outlink->src;
+    ShufflePixelsContext *s = ctx->priv;
+    AVFilterLink *inlink = ctx->inputs[0];
+    const AVPixFmtDescriptor *desc;
+    int ret;
+
+    if (s->seed == -1)
+        s->seed = av_get_random_seed();
+    av_lfg_init(&s->c, s->seed);
+
+    desc = av_pix_fmt_desc_get(outlink->format);
+    if (!desc)
+        return AVERROR_BUG;
+    s->nb_planes = av_pix_fmt_count_planes(outlink->format);
+    s->depth = desc->comp[0].depth;
+
+    if ((ret = av_image_fill_linesizes(s->linesize, inlink->format, inlink->w)) < 0)
+        return ret;
+
+    s->planewidth[1] = s->planewidth[2] = AV_CEIL_RSHIFT(inlink->w, desc->log2_chroma_w);
+    s->planewidth[0] = s->planewidth[3] = inlink->w;
+
+    s->planeheight[1] = s->planeheight[2] = AV_CEIL_RSHIFT(inlink->h, desc->log2_chroma_h);
+    s->planeheight[0] = s->planeheight[3] = inlink->h;
+
+    s->map = av_calloc(inlink->w * inlink->h, sizeof(*s->map));
+    if (!s->map)
+        return AVERROR(ENOMEM);
+
+    switch (s->mode) {
+    case 0:
+        s->shuffle_pixels = s->depth <= 8 ? shuffle_horizontal8 : shuffle_horizontal16;
+        s->nb_blocks = (s->planewidth[0] + s->block_w - 1) / s->block_w;
+        break;
+    case 1:
+        s->shuffle_pixels = s->depth <= 8 ? shuffle_vertical8 : shuffle_vertical16;
+        s->nb_blocks = (s->planeheight[0] + s->block_h - 1) / s->block_h;
+        break;
+    case 2:
+        s->shuffle_pixels = s->depth <= 8 ? shuffle_block8 : shuffle_block16;
+        s->nb_blocks = (s->planeheight[0] / s->block_h) *
+                       (s->planewidth[0]  / s->block_w);
+        break;
+    default:
+        av_assert0(0);
+    }
+
+    s->used = av_calloc(s->nb_blocks, sizeof(*s->used));
+    if (!s->used)
+        return AVERROR(ENOMEM);
+
+    switch (s->mode) {
+    case 0:
+        make_horizontal_map(ctx);
+        break;
+    case 1:
+        make_vertical_map(ctx);
+        break;
+    case 2:
+        make_block_map(ctx);
+        break;
+    default:
+        av_assert0(0);
+    }
+
+    return 0;
+}
+
+static int filter_frame(AVFilterLink *inlink, AVFrame *in)
+{
+    AVFilterContext *ctx = inlink->dst;
+    ShufflePixelsContext *s = ctx->priv;
+    AVFrame *out = ff_get_video_buffer(ctx->outputs[0], in->width, in->height);
+    ThreadData td;
+    int ret;
+
+    ret = av_frame_copy_props(out, in);
+    if (ret < 0) {
+        av_frame_free(&out);
+        goto fail;
+    }
+
+    td.out = out;
+    td.in = in;
+    ctx->internal->execute(ctx, s->shuffle_pixels, &td, NULL, FFMIN(s->planeheight[1], ff_filter_get_nb_threads(ctx)));
+
+    av_frame_free(&in);
+    return ff_filter_frame(ctx->outputs[0], out);
+fail:
+    av_frame_free(&in);
+    return ret;
+}
+
+static av_cold void uninit(AVFilterContext *ctx)
+{
+    ShufflePixelsContext *s = ctx->priv;
+
+    av_freep(&s->map);
+    av_freep(&s->used);
+}
+
+#define OFFSET(x) offsetof(ShufflePixelsContext, x)
+#define FLAGS (AV_OPT_FLAG_FILTERING_PARAM | AV_OPT_FLAG_VIDEO_PARAM)
+static const AVOption shufflepixels_options[] = {
+    { "direction",  "set shuffle direction",  OFFSET(direction), AV_OPT_TYPE_INT, {.i64=0}, 0, 1, FLAGS, "dir" },
+    { "d",          "set shuffle direction",  OFFSET(direction), AV_OPT_TYPE_INT, {.i64=0}, 0, 1, FLAGS, "dir" },
+    {  "forward",    0,  0,  AV_OPT_TYPE_CONST,     {.i64=0}, 0,  0, FLAGS, "dir" },
+    {  "inverse",    0,  0,  AV_OPT_TYPE_CONST,     {.i64=1}, 0,  0, FLAGS, "dir" },
+    { "mode",       "set shuffle mode",  OFFSET(mode), AV_OPT_TYPE_INT, {.i64=0}, 0, 2, FLAGS, "mode" },
+    { "m",          "set shuffle mode",  OFFSET(mode), AV_OPT_TYPE_INT, {.i64=0}, 0, 2, FLAGS, "mode" },
+    {  "horizontal",  0,  0,  AV_OPT_TYPE_CONST,     {.i64=0}, 0,  0, FLAGS, "mode" },
+    {  "vertical",    0,  0,  AV_OPT_TYPE_CONST,     {.i64=1}, 0,  0, FLAGS, "mode" },
+    {  "block",       0,  0,  AV_OPT_TYPE_CONST,     {.i64=2}, 0,  0, FLAGS, "mode" },
+    { "width",      "set block width",  OFFSET(block_w), AV_OPT_TYPE_INT, {.i64=10}, 1, 8000, FLAGS },
+    { "w",          "set block width",  OFFSET(block_w), AV_OPT_TYPE_INT, {.i64=10}, 1, 8000, FLAGS },
+    { "height",     "set block height", OFFSET(block_h), AV_OPT_TYPE_INT, {.i64=10}, 1, 8000, FLAGS },
+    { "h",          "set block height", OFFSET(block_h), AV_OPT_TYPE_INT, {.i64=10}, 1, 8000, FLAGS },
+    { "seed",       "set random seed",  OFFSET(seed),   AV_OPT_TYPE_INT64, {.i64=-1}, -1, UINT_MAX, FLAGS },
+    { "s",          "set random seed",  OFFSET(seed),   AV_OPT_TYPE_INT64, {.i64=-1}, -1, UINT_MAX, FLAGS },
+    { NULL },
+};
+
+AVFILTER_DEFINE_CLASS(shufflepixels);
+
+static const AVFilterPad shufflepixels_inputs[] = {
+    {
+        .name         = "default",
+        .type         = AVMEDIA_TYPE_VIDEO,
+        .filter_frame = filter_frame,
+    },
+    { NULL },
+};
+
+static const AVFilterPad shufflepixels_outputs[] = {
+    {
+        .name          = "default",
+        .type          = AVMEDIA_TYPE_VIDEO,
+        .config_props  = config_output,
+    },
+    { NULL },
+};
+
+AVFilter ff_vf_shufflepixels = {
+    .name          = "shufflepixels",
+    .description   = NULL_IF_CONFIG_SMALL("Shuffle video pixels."),
+    .priv_size     = sizeof(ShufflePixelsContext),
+    .priv_class    = &shufflepixels_class,
+    .query_formats = query_formats,
+    .uninit        = uninit,
+    .inputs        = shufflepixels_inputs,
+    .outputs       = shufflepixels_outputs,
+    .flags         = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC | AVFILTER_FLAG_SLICE_THREADS,
+};