lavfi: add untile filter.

Changelog

@@ -70,6 +70,7 @@ version <next>:
 - NotchLC decoder
 - gradients source video filter
 - MediaFoundation encoder wrapper
+- untile filter
 
 
 version 4.2:

doc/filters.texi

@@ -18197,10 +18197,13 @@ ffmpeg -i in.avi -vf thumbnail,scale=300:200 -frames:v 1 out.png
 @end example
 @end itemize
+@anchor{tile}
 @section tile
 Tile several successive frames together.
+The @ref{untile} filter can do the reverse.
+
 The filter accepts the following options:
 @table @option
@@ -18984,6 +18987,37 @@ unsharp=7:7:-2:7:7:-2
 @end example
 @end itemize
+@anchor{untile}
+@section untile
+
+Decompose a video made of tiled images into the individual images.
+
+The frame rate of the output video is the frame rate of the input video
+multiplied by the number of tiles.
+
+This filter does the reverse of @ref{tile}.
+
+The filter accepts the following options:
+
+@table @option
+
+@item layout
+Set the grid size (i.e. the number of lines and columns). For the syntax of
+this option, check the
+@ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
+@end table
+
+@subsection Examples
+
+@itemize
+@item
+Produce a 1-second video from a still image file made of 25 frames stacked
+vertically, like an analogic film reel:
+@example
+ffmpeg -r 1 -i image.jpg -vf untile=1x25 movie.mkv
+@end example
+@end itemize
+
 @section uspp
 Apply ultra slow/simple postprocessing filter that compresses and decompresses

libavfilter/Makefile

@@ -436,6 +436,7 @@ OBJS-$(CONFIG_UNPREMULTIPLY_FILTER)          += vf_premultiply.o framesync.o
 OBJS-$(CONFIG_UNSHARP_FILTER)                += vf_unsharp.o
 OBJS-$(CONFIG_UNSHARP_OPENCL_FILTER)         += vf_unsharp_opencl.o opencl.o \
                                                 opencl/unsharp.o
+OBJS-$(CONFIG_UNTILE_FILTER)                 += vf_untile.o
 OBJS-$(CONFIG_USPP_FILTER)                   += vf_uspp.o
 OBJS-$(CONFIG_V360_FILTER)                   += vf_v360.o
 OBJS-$(CONFIG_VAGUEDENOISER_FILTER)          += vf_vaguedenoiser.o

libavfilter/allfilters.c

@@ -415,6 +415,7 @@ extern AVFilter ff_vf_trim;
 extern AVFilter ff_vf_unpremultiply;
 extern AVFilter ff_vf_unsharp;
 extern AVFilter ff_vf_unsharp_opencl;
+extern AVFilter ff_vf_untile;
 extern AVFilter ff_vf_uspp;
 extern AVFilter ff_vf_v360;
 extern AVFilter ff_vf_vaguedenoiser;

libavfilter/version.h

@@ -30,7 +30,7 @@
 #include "libavutil/version.h"
 
 #define LIBAVFILTER_VERSION_MAJOR   7
-#define LIBAVFILTER_VERSION_MINOR  82
+#define LIBAVFILTER_VERSION_MINOR  83
 #define LIBAVFILTER_VERSION_MICRO 100
 
 

libavfilter/vf_untile.c

+/*
+ * Copyright (c) 2020 Nicolas George
+ *
+ * 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 "avfilter.h"
+#include "formats.h"
+#include "filters.h"
+
+typedef struct UntileContext {
+    const AVClass *class;
+    unsigned w, h;
+    unsigned current;
+    unsigned nb_frames;
+    AVFrame *frame;
+    const AVPixFmtDescriptor *desc;
+    int64_t dpts, pts;
+    int max_step[4];
+} UntileContext;
+
+#define OFFSET(x) offsetof(UntileContext, x)
+#define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
+
+static const AVOption untile_options[] = {
+    { "layout", "set grid size", OFFSET(w), AV_OPT_TYPE_IMAGE_SIZE,
+        {.str = "6x5"}, 0, 0, FLAGS },
+    { NULL }
+};
+
+AVFILTER_DEFINE_CLASS(untile);
+
+static av_cold int init(AVFilterContext *ctx)
+{
+    UntileContext *s = ctx->priv;
+
+    if (s->w > UINT_MAX / s->h) {
+        av_log(ctx, AV_LOG_ERROR, "Tile size %ux%u is insane.\n",
+               s->w, s->h);
+        return AVERROR(EINVAL);
+    }
+    s->nb_frames = s->w * s->h;
+    return 0;
+}
+
+static int query_formats(AVFilterContext *ctx)
+{
+    AVFilterFormats *formats = NULL;
+    int ret;
+
+    ret = ff_formats_pixdesc_filter(&formats, 0,
+                                    AV_PIX_FMT_FLAG_HWACCEL |
+                                    AV_PIX_FMT_FLAG_BITSTREAM |
+                                    FF_PIX_FMT_FLAG_SW_FLAT_SUB);
+    if (ret < 0)
+        return ret;
+    return ff_set_common_formats(ctx, formats);
+}
+
+static int config_output(AVFilterLink *outlink)
+{
+    AVFilterContext *ctx = outlink->src;
+    UntileContext *s = ctx->priv;
+    AVFilterLink *inlink = ctx->inputs[0];
+    AVRational dt;
+
+    s->desc = av_pix_fmt_desc_get(outlink->format);
+    if (inlink->w % (s->w << s->desc->log2_chroma_w) ||
+        inlink->h % (s->h << s->desc->log2_chroma_h)) {
+        av_log(ctx, AV_LOG_ERROR,
+               "Input resolution %ux%u not multiple of layout %ux%u.\n",
+               inlink->w, inlink->h, s->w, s->h);
+        return AVERROR(EINVAL);
+    }
+    outlink->w = inlink->w / s->w;
+    outlink->h = inlink->h / s->h;
+    outlink->sample_aspect_ratio = inlink->sample_aspect_ratio;
+    outlink->frame_rate = av_mul_q(inlink->frame_rate, av_make_q(s->nb_frames, 1));
+    if (outlink->frame_rate.num)
+        dt = av_inv_q(outlink->frame_rate);
+    else
+        dt = av_mul_q(inlink->time_base, av_make_q(1, s->nb_frames));
+    outlink->time_base = av_gcd_q(inlink->time_base, dt, AV_TIME_BASE / 2, AV_TIME_BASE_Q);
+    s->dpts = av_rescale_q(1, dt, outlink->time_base);
+    av_log(ctx, AV_LOG_VERBOSE, "frame interval: %"PRId64"*%d/%d\n",
+           s->dpts, dt.num, dt.den);
+    av_image_fill_max_pixsteps(s->max_step, NULL, s->desc);
+    return 0;
+}
+
+static int activate(AVFilterContext *ctx)
+{
+    UntileContext *s = ctx->priv;
+    AVFilterLink *inlink = ctx->inputs[0];
+    AVFilterLink *outlink = ctx->outputs[0];
+    AVFrame *out;
+    int i, x, y, ret;
+
+    FF_FILTER_FORWARD_STATUS_BACK(outlink, inlink);
+    if (!s->frame) {
+        ret = ff_inlink_consume_frame(inlink, &s->frame);
+        if (ret < 0)
+            return ret;
+        if (ret)
+            s->pts = av_rescale_q(s->frame->pts, inlink->time_base, outlink->time_base);
+    }
+    if (s->frame) {
+        if (s->current == s->nb_frames - 1) {
+            out = s->frame;
+            s->frame = NULL;
+        } else {
+            out = av_frame_clone(s->frame);
+            if (!out)
+                return AVERROR(ENOMEM);
+        }
+        x = outlink->w * (s->current % s->w);
+        y = outlink->h * (s->current / s->w);
+        out->width = outlink->w;
+        out->height = outlink->h;
+        out->data[0] += y * out->linesize[0];
+        out->data[0] += x * s->max_step[0];
+        if (!(s->desc->flags & AV_PIX_FMT_FLAG_PAL || s->desc->flags & FF_PSEUDOPAL)) {
+            for (i = 1; i < 3; i ++) {
+                if (out->data[i]) {
+                    out->data[i] += (y >> s->desc->log2_chroma_w) * out->linesize[i];
+                    out->data[i] += (x >> s->desc->log2_chroma_h) * s->max_step[i];
+                }
+            }
+        }
+        if (out->data[3]) {
+            out->data[3] += y * out->linesize[3];
+            out->data[3] += x * s->max_step[3];
+        }
+        out->pts = s->pts;
+        s->pts += s->dpts;
+        if (++s->current == s->nb_frames)
+            s->current = 0;
+        return ff_filter_frame(outlink, out);
+    }
+    FF_FILTER_FORWARD_STATUS(inlink, outlink);
+    FF_FILTER_FORWARD_WANTED(outlink, inlink);
+    return FFERROR_NOT_READY;
+
+}
+
+static av_cold void uninit(AVFilterContext *ctx)
+{
+    UntileContext *s = ctx->priv;
+
+    av_frame_free(&s->frame);
+}
+
+static const AVFilterPad untile_inputs[] = {
+    {
+        .name         = "default",
+        .type         = AVMEDIA_TYPE_VIDEO,
+    },
+    { NULL }
+};
+
+static const AVFilterPad untile_outputs[] = {
+    {
+        .name          = "default",
+        .type          = AVMEDIA_TYPE_VIDEO,
+        .config_props  = config_output,
+    },
+    { NULL }
+};
+
+AVFilter ff_vf_untile = {
+    .name          = "untile",
+    .description   = NULL_IF_CONFIG_SMALL("Untile a frame into a sequence of frames."),
+    .init          = init,
+    .uninit        = uninit,
+    .query_formats = query_formats,
+    .activate      = activate,
+    .priv_size     = sizeof(UntileContext),
+    .inputs        = untile_inputs,
+    .outputs       = untile_outputs,
+    .priv_class    = &untile_class,
+};

tests/fate/filter-video.mak

@@ -396,6 +396,9 @@ fate-filter-trim-time: CMD = framecrc -i $(SRC) -vf trim=0:0.09
 
 FATE_FILTER_VSYNTH-$(CONFIG_TRIM_FILTER) += $(FATE_TRIM)
 
+FATE_FILTER-$(call ALLYES, TESTSRC2_FILTER UNTILE_FILTER) += fate-filter-untile
+fate-filter-untile: CMD = framecrc -lavfi testsrc2=d=1:r=2,untile=2x2
+
 FATE_FILTER_VSYNTH-$(CONFIG_UNSHARP_FILTER) += fate-filter-unsharp
 fate-filter-unsharp: CMD = framecrc -c:v pgmyuv -i $(SRC) -vf unsharp=11:11:-1.5:11:11:-1.5
 

tests/ref/fate/filter-untile

+#tb 0: 1/8
+#media_type 0: video
+#codec_id 0: rawvideo
+#dimensions 0: 160x120
+#sar 0: 1/1
+0,          0,          0,        1,    28800, 0xb3725302
+0,          1,          1,        1,    28800, 0xf9612057
+0,          2,          2,        1,    28800, 0x9b207db0
+0,          3,          3,        1,    28800, 0x1331c2d5
+0,          4,          4,        1,    28800, 0x2edf3ee4
+0,          5,          5,        1,    28800, 0x84105711
+0,          6,          6,        1,    28800, 0xa7a35f25
+0,          7,          7,        1,    28800, 0xa9c49677