avfilter/vf_guided: support single input

Support single input for guided filter by adding guidance mode.
If the guidance mode is off, single input is required. And
edge-preserving smoothing is conducted. If the mode is on, two
inputs are needed. The second input serves as the guidance. For
this mode, more tasks are supported, such as detail enhancement,
dehazing and so on.

Signed-off-by: Xuewei Meng <xwmeng96@gmail.com>
Reviewed-by: Steven Liu <lq@chinaffmpeg.org>

doc/filters.texi

@@ -12995,8 +12995,6 @@ greyedge=difford=1:minknorm=0:sigma=2
 
 @section guided
 Apply guided filter for edge-preserving smoothing, dehazing and so on.
-This filter requires two inputs of same resolution and pixel format.
-The second input serves as the reference.
 
 The filter accepts the following options:
 @table @option
@@ -13017,6 +13015,12 @@ Set subsampling ratio for @code{fast} mode.
 Range is 2 to 64. Default is 4.
 No subsampling occurs in @code{basic} mode.
 
+@item guidance
+Set guidance mode. Can be @code{off} or @code{on}. Default is @code{off}.
+If @code{off}, single input is required.
+If @code{on}, two inputs of the same resolution and pixel format are required.
+The second input serves as the guidance.
+
 @item planes
 Set planes to filter. Default is first only.
 @end table
@@ -13029,7 +13033,7 @@ This filter supports the all above options as @ref{commands}.
 @item
 Edge-preserving smoothing with guided filter:
 @example
-ffmpeg -i in.png -i in.png -filter_complex guided out.png
+ffmpeg -i in.png -vf guided out.png
 @end example
 
 @item
@@ -13037,7 +13041,7 @@ Dehazing, structure-transferring filtering, detail enhancement with guided filte
 For the generation of guidance image, refer to paper "Guided Image Filtering".
 See: @url{http://kaiminghe.com/publications/pami12guidedfilter.pdf}.
 @example
-ffmpeg -i in.png -i guidance.png -filter_complex guided out.png
+ffmpeg -i in.png -i guidance.png -filter_complex guided=guidance=on out.png
 @end example
 
 @end itemize

libavfilter/vf_guided.c

@@ -22,6 +22,7 @@
 #include "libavutil/opt.h"
 #include "libavutil/pixdesc.h"
 #include "avfilter.h"
+#include "filters.h"
 #include "formats.h"
 #include "framesync.h"
 #include "internal.h"
@@ -33,6 +34,12 @@ enum FilterModes {
     NB_MODES,
 };
 
+enum GuidanceModes {
+    OFF,
+    ON,
+    NB_GUIDANCE_MODES,
+};
+
 typedef struct GuidedContext {
     const AVClass *class;
     FFFrameSync fs;
@@ -41,7 +48,7 @@ typedef struct GuidedContext {
     float eps;
     int mode;
     int sub;
-
+    int guidance;
     int planes;
 
     int width;
@@ -65,6 +72,9 @@ static const AVOption guided_options[] = {
     { "basic",    "basic guided filter",                              0,                AV_OPT_TYPE_CONST, {.i64 = BASIC},     0,                     0, FLAGS, "mode" },
     { "fast",     "fast guided filter",                               0,                AV_OPT_TYPE_CONST, {.i64 = FAST },     0,                     0, FLAGS, "mode" },
     { "sub",      "subsampling ratio for fast mode",                  OFFSET(sub),      AV_OPT_TYPE_INT,   {.i64 = 4    },     2,                    64, FLAGS },
+    { "guidance", "set guidance mode (0: off mode; 1: on mode)",      OFFSET(guidance), AV_OPT_TYPE_INT,   {.i64 = OFF  },   OFF, NB_GUIDANCE_MODES - 1, FLAGS, "guidance" },
+    { "off",      "only one input is enabled",                        0,                AV_OPT_TYPE_CONST, {.i64 = OFF  },     0,                     0, FLAGS, "guidance" },
+    { "on",       "two inputs are required",                          0,                AV_OPT_TYPE_CONST, {.i64 = ON   },     0,                     0, FLAGS, "guidance" },
     { "planes",   "set planes to filter",                             OFFSET(planes),   AV_OPT_TYPE_INT,   {.i64 = 1    },     0,                   0xF, FLAGS },
     { NULL }
 };
@@ -149,16 +159,6 @@ static int config_input(AVFilterLink *inlink)
     GuidedContext *s = ctx->priv;
     const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
 
-    if (ctx->inputs[0]->w != ctx->inputs[1]->w ||
-        ctx->inputs[0]->h != ctx->inputs[1]->h) {
-        av_log(ctx, AV_LOG_ERROR, "Width and height of input videos must be same.\n");
-        return AVERROR(EINVAL);
-    }
-    if (ctx->inputs[0]->format != ctx->inputs[1]->format) {
-        av_log(ctx, AV_LOG_ERROR, "Inputs must be of same pixel format.\n");
-        return AVERROR(EINVAL);
-    }
-
     if (s->mode == BASIC) {
         s->sub = 1;
     }
@@ -304,47 +304,54 @@ end:
 GUIDED(uint8_t, byte)
 GUIDED(uint16_t, word)
 
-static int process_frame(FFFrameSync *fs)
+static int filter_frame(AVFilterContext *ctx, AVFrame **out, AVFrame *in, AVFrame *ref)
 {
-    AVFilterContext *ctx = fs->parent;
+    GuidedContext *s = ctx->priv;
-    GuidedContext *s = fs->opaque;
     AVFilterLink *outlink = ctx->outputs[0];
-    AVFrame *out_frame = NULL, *main_frame = NULL, *ref_frame = NULL;
+    *out = ff_get_video_buffer(outlink, outlink->w, outlink->h);
-    int ret;
+    if (!*out)
-
-    ret = ff_framesync_dualinput_get(fs, &main_frame, &ref_frame);
-    if (ret < 0)
-        return ret;
-
-    out_frame = ff_get_video_buffer(outlink, outlink->w, outlink->h);
-    if (!out_frame) {
-        av_frame_free(&main_frame);
         return AVERROR(ENOMEM);
-    }
+    av_frame_copy_props(*out, in);
-    av_frame_copy_props(out_frame, main_frame);
 
     for (int plane = 0; plane < s->nb_planes; plane++) {
         if (!(s->planes & (1 << plane))) {
-            av_image_copy_plane(out_frame->data[plane], out_frame->linesize[plane],
+            av_image_copy_plane((*out)->data[plane], (*out)->linesize[plane],
-                                main_frame->data[plane], main_frame->linesize[plane],
+                                in->data[plane], in->linesize[plane],
                                 s->planewidth[plane] * ((s->depth + 7) / 8), s->planeheight[plane]);
             continue;
         }
         if (s->depth <= 8)
-           guided_byte(ctx, s, main_frame->data[plane], ref_frame->data[plane], out_frame->data[plane], s->radius, s->eps,
+           guided_byte(ctx, s, in->data[plane], ref->data[plane], (*out)->data[plane], s->radius, s->eps,
                        s->planewidth[plane], s->planeheight[plane],
-                       main_frame->linesize[plane], ref_frame->linesize[plane], out_frame->linesize[plane], (1 << s->depth) - 1.f);
+                       in->linesize[plane], ref->linesize[plane], (*out)->linesize[plane], (1 << s->depth) - 1.f);
         else
-           guided_word(ctx, s, main_frame->data[plane], ref_frame->data[plane], out_frame->data[plane], s->radius, s->eps,
+           guided_word(ctx, s, in->data[plane], ref->data[plane], (*out)->data[plane], s->radius, s->eps,
                        s->planewidth[plane], s->planeheight[plane],
-                       main_frame->linesize[plane] / 2, ref_frame->linesize[plane] / 2, out_frame->linesize[plane] / 2, (1 << s->depth) - 1.f);
+                       in->linesize[plane] / 2, ref->linesize[plane] / 2, (*out)->linesize[plane] / 2, (1 << s->depth) - 1.f);
+    }
+
+    return 0;
+}
+
+static int process_frame(FFFrameSync *fs)
+{
+    AVFilterContext *ctx = fs->parent;
+    AVFilterLink *outlink = ctx->outputs[0];
+    AVFrame *out_frame = NULL, *main_frame = NULL, *ref_frame = NULL;
+    int ret;
+    ret = ff_framesync_dualinput_get(fs, &main_frame, &ref_frame);
+    if (ret < 0)
+        return ret;
+
+    ret = filter_frame(ctx, &out_frame, main_frame, ref_frame);
+    if (ret < 0) {
+        return ret;
     }
     av_frame_free(&main_frame);
 
     return ff_filter_frame(outlink, out_frame);
 }
 
-
 static int config_output(AVFilterLink *outlink)
 {
     AVFilterContext *ctx = outlink->src;
@@ -354,12 +361,27 @@ static int config_output(AVFilterLink *outlink)
     FFFrameSyncIn *in;
     int ret;
 
+    if (s->guidance == ON) {
+        if (ctx->inputs[0]->w != ctx->inputs[1]->w ||
+            ctx->inputs[0]->h != ctx->inputs[1]->h) {
+            av_log(ctx, AV_LOG_ERROR, "Width and height of input videos must be same.\n");
+            return AVERROR(EINVAL);
+        }
+        if (ctx->inputs[0]->format != ctx->inputs[1]->format) {
+            av_log(ctx, AV_LOG_ERROR, "Inputs must be of same pixel format.\n");
+            return AVERROR(EINVAL);
+        }
+    }
 
     outlink->w = mainlink->w;
     outlink->h = mainlink->h;
     outlink->time_base = mainlink->time_base;
     outlink->sample_aspect_ratio = mainlink->sample_aspect_ratio;
     outlink->frame_rate = mainlink->frame_rate;
+
+    if (s->guidance == OFF)
+        return 0;
+
     if ((ret = ff_framesync_init(&s->fs, ctx, 2)) < 0)
         return ret;
 
@@ -383,22 +405,66 @@ static int config_output(AVFilterLink *outlink)
 static int activate(AVFilterContext *ctx)
 {
     GuidedContext *s = ctx->priv;
+    AVFrame *frame = NULL;
+    AVFrame *out = NULL;
+    int ret, status;
+    int64_t pts;
+    if (s->guidance)
         return ff_framesync_activate(&s->fs);
+
+    FF_FILTER_FORWARD_STATUS_BACK(ctx->outputs[0], ctx->inputs[0]);
+
+    if ((ret = ff_inlink_consume_frame(ctx->inputs[0], &frame)) > 0) {
+        ret = filter_frame(ctx, &out, frame, frame);
+        av_frame_free(&frame);
+        if (ret < 0)
+            return ret;
+        ret = ff_filter_frame(ctx->outputs[0], out);
+    }
+    if (ret < 0)
+        return ret;
+    if (ff_inlink_acknowledge_status(ctx->inputs[0], &status, &pts)) {
+        ff_outlink_set_status(ctx->outputs[0], status, pts);
+        return 0;
+    }
+    if (ff_outlink_frame_wanted(ctx->outputs[0]))
+        ff_inlink_request_frame(ctx->inputs[0]);
+    return 0;
 }
 
 static av_cold int init(AVFilterContext *ctx)
 {
+    GuidedContext *s = ctx->priv;
+    AVFilterPad pad = { 0 };
+    int ret;
+
+    pad.type         = AVMEDIA_TYPE_VIDEO;
+    pad.name         = "source";
+    pad.config_props = config_input;
+
+    if ((ret = ff_insert_inpad(ctx, 0, &pad)) < 0)
+        return ret;
+
+    if (s->guidance == ON) {
+        pad.type         = AVMEDIA_TYPE_VIDEO;
+        pad.name         = "guidance";
+        pad.config_props = NULL;
+
+        if ((ret = ff_insert_inpad(ctx, 1, &pad)) < 0)
+            return ret;
+    }
+
     return 0;
 }
 
 static av_cold void uninit(AVFilterContext *ctx)
 {
     GuidedContext *s = ctx->priv;
+    if (s->guidance == ON)
         ff_framesync_uninit(&s->fs);
     return;
 }
 
-
 static int process_command(AVFilterContext *ctx,
                            const char *cmd,
                            const char *arg,
@@ -414,18 +480,6 @@ static int process_command(AVFilterContext *ctx,
     return 0;
 }
 
-static const AVFilterPad guided_inputs[] = {
-    {
-        .name         = "main",
-        .type         = AVMEDIA_TYPE_VIDEO,
-    },{
-        .name         = "reference",
-        .type         = AVMEDIA_TYPE_VIDEO,
-        .config_props = config_input,
-    },
-    { NULL }
-};
-
 static const AVFilterPad guided_outputs[] = {
     {
         .name = "default",
@@ -444,7 +498,7 @@ const AVFilter ff_vf_guided = {
     .priv_size       = sizeof(GuidedContext),
     .priv_class      = &guided_class,
     .activate        = activate,
-    .inputs          = guided_inputs,
+    .inputs          = NULL,
     .outputs         = guided_outputs,
     .flags           = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC | AVFILTER_FLAG_SLICE_THREADS,
     .process_command = process_command,