diff --git a/libavfilter/stack_internal.c b/libavfilter/stack_internal.c
new file mode 100644
index 0000000000..57661e1c97
--- /dev/null
+++ b/libavfilter/stack_internal.c
@@ -0,0 +1,355 @@
+/*
+ * 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
+ */
+
+#define OFFSET(x) offsetof(StackHWContext, x)
+#define FLAGS (AV_OPT_FLAG_VIDEO_PARAM | AV_OPT_FLAG_FILTERING_PARAM)
+
+#define SET_OUTPUT_REGION(region, rx, ry, rw, rh) do {  \
+        region->x = rx;                                 \
+        region->y = ry;                                 \
+        region->width = rw;                             \
+        region->height = rh;                            \
+    } while (0)
+
+static int init_framesync(AVFilterContext *avctx)
+{
+    StackBaseContext *sctx = avctx->priv;
+    int ret;
+
+    ret = ff_framesync_init(&sctx->fs, avctx, avctx->nb_inputs);
+    if (ret < 0)
+        return ret;
+
+    sctx->fs.on_event = process_frame;
+    sctx->fs.opaque = sctx;
+
+    for (int i = 0; i < sctx->nb_inputs; i++) {
+        FFFrameSyncIn *in = &sctx->fs.in[i];
+
+        in->before = EXT_STOP;
+        in->after = sctx->shortest ? EXT_STOP : EXT_INFINITY;
+        in->sync = 1;
+        in->time_base = avctx->inputs[i]->time_base;
+    }
+
+    return ff_framesync_configure(&sctx->fs);
+}
+
+static int config_comm_output(AVFilterLink *outlink)
+{
+    AVFilterContext *avctx = outlink->src;
+    StackBaseContext *sctx = avctx->priv;
+    AVFilterLink *inlink0 = avctx->inputs[0];
+    int width, height, ret;
+
+    if (sctx->mode == STACK_H) {
+        height = sctx->tile_height;
+        width = 0;
+
+        if (!height)
+            height = inlink0->h;
+
+        for (int i = 0; i < sctx->nb_inputs; i++) {
+            AVFilterLink *inlink = avctx->inputs[i];
+            StackItemRegion *region = &sctx->regions[i];
+
+            SET_OUTPUT_REGION(region, width, 0, av_rescale(height, inlink->w, inlink->h), height);
+            width += av_rescale(height, inlink->w, inlink->h);
+        }
+    } else if (sctx->mode == STACK_V) {
+        height = 0;
+        width = sctx->tile_width;
+
+        if (!width)
+            width = inlink0->w;
+
+        for (int i = 0; i < sctx->nb_inputs; i++) {
+            AVFilterLink *inlink = avctx->inputs[i];
+            StackItemRegion *region = &sctx->regions[i];
+
+            SET_OUTPUT_REGION(region, 0, height, width, av_rescale(width, inlink->h, inlink->w));
+            height += av_rescale(width, inlink->h, inlink->w);
+        }
+    } else if (sctx->nb_grid_rows && sctx->nb_grid_columns) {
+        int xpos = 0, ypos = 0;
+        int ow, oh, k = 0;
+
+        ow = sctx->tile_width;
+        oh = sctx->tile_height;
+
+        if (!ow || !oh) {
+            ow = avctx->inputs[0]->w;
+            oh = avctx->inputs[0]->h;
+        }
+
+        for (int i = 0; i < sctx->nb_grid_columns; i++) {
+            ypos = 0;
+
+            for (int j = 0; j < sctx->nb_grid_rows; j++) {
+                StackItemRegion *region = &sctx->regions[k++];
+
+                SET_OUTPUT_REGION(region, xpos, ypos, ow, oh);
+                ypos += oh;
+            }
+
+            xpos += ow;
+        }
+
+        width = ow * sctx->nb_grid_columns;
+        height = oh * sctx->nb_grid_rows;
+    } else {
+        char *arg, *p = sctx->layout, *saveptr = NULL;
+        char *arg2, *p2, *saveptr2 = NULL;
+        char *arg3, *p3, *saveptr3 = NULL;
+        int xpos, ypos, size;
+        int ow, oh;
+
+        width = avctx->inputs[0]->w;
+        height = avctx->inputs[0]->h;
+
+        for (int i = 0; i < sctx->nb_inputs; i++) {
+            AVFilterLink *inlink = avctx->inputs[i];
+            StackItemRegion *region = &sctx->regions[i];
+
+            ow = inlink->w;
+            oh = inlink->h;
+
+            if (!(arg = av_strtok(p, "|", &saveptr)))
+                return AVERROR(EINVAL);
+
+            p = NULL;
+            p2 = arg;
+            xpos = ypos = 0;
+
+            for (int j = 0; j < 3; j++) {
+                if (!(arg2 = av_strtok(p2, "_", &saveptr2))) {
+                    if (j == 2)
+                        break;
+                    else
+                        return AVERROR(EINVAL);
+                }
+
+                p2 = NULL;
+                p3 = arg2;
+
+                if (j == 2) {
+                    if ((ret = av_parse_video_size(&ow, &oh, p3)) < 0) {
+                        av_log(avctx, AV_LOG_ERROR, "Invalid size '%s'\n", p3);
+                        return ret;
+                    }
+
+                    break;
+                }
+
+                while ((arg3 = av_strtok(p3, "+", &saveptr3))) {
+                    p3 = NULL;
+                    if (sscanf(arg3, "w%d", &size) == 1) {
+                        if (size == i || size < 0 || size >= sctx->nb_inputs)
+                            return AVERROR(EINVAL);
+
+                        if (!j)
+                            xpos += sctx->regions[size].width;
+                        else
+                            ypos += sctx->regions[size].width;
+                    } else if (sscanf(arg3, "h%d", &size) == 1) {
+                        if (size == i || size < 0 || size >= sctx->nb_inputs)
+                            return AVERROR(EINVAL);
+
+                        if (!j)
+                            xpos += sctx->regions[size].height;
+                        else
+                            ypos += sctx->regions[size].height;
+                    } else if (sscanf(arg3, "%d", &size) == 1) {
+                        if (size < 0)
+                            return AVERROR(EINVAL);
+
+                        if (!j)
+                            xpos += size;
+                        else
+                            ypos += size;
+                    } else {
+                        return AVERROR(EINVAL);
+                    }
+                }
+            }
+
+            SET_OUTPUT_REGION(region, xpos, ypos, ow, oh);
+            width = FFMAX(width,  xpos + ow);
+            height = FFMAX(height, ypos + oh);
+        }
+
+    }
+
+    outlink->w = width;
+    outlink->h = height;
+    outlink->frame_rate = inlink0->frame_rate;
+    outlink->sample_aspect_ratio = inlink0->sample_aspect_ratio;
+
+    for (int i = 1; i < sctx->nb_inputs; i++) {
+        AVFilterLink *inlink = avctx->inputs[i];
+        if (outlink->frame_rate.num != inlink->frame_rate.num ||
+            outlink->frame_rate.den != inlink->frame_rate.den) {
+            av_log(avctx, AV_LOG_VERBOSE,
+                    "Video inputs have different frame rates, output will be VFR\n");
+            outlink->frame_rate = av_make_q(1, 0);
+            break;
+        }
+    }
+
+    ret = init_framesync(avctx);
+    if (ret < 0)
+        return ret;
+
+    outlink->time_base = sctx->fs.time_base;
+
+    return 0;
+}
+
+static int stack_init(AVFilterContext *avctx)
+{
+    StackBaseContext *sctx = avctx->priv;
+    int ret;
+
+    if (!strcmp(avctx->filter->name, HSTACK_NAME))
+        sctx->mode = STACK_H;
+    else if (!strcmp(avctx->filter->name, VSTACK_NAME))
+        sctx->mode = STACK_V;
+    else {
+        int is_grid;
+
+        av_assert0(strcmp(avctx->filter->name, XSTACK_NAME) == 0);
+        sctx->mode = STACK_X;
+        is_grid = sctx->nb_grid_rows && sctx->nb_grid_columns;
+
+        if (sctx->layout && is_grid) {
+            av_log(avctx, AV_LOG_ERROR, "Both layout and grid were specified. Only one is allowed.\n");
+            return AVERROR(EINVAL);
+        }
+
+        if (!sctx->layout && !is_grid) {
+            if (sctx->nb_inputs == 2) {
+                sctx->nb_grid_rows = 1;
+                sctx->nb_grid_columns = 2;
+                is_grid = 1;
+            } else {
+                av_log(avctx, AV_LOG_ERROR, "No layout or grid specified.\n");
+                return AVERROR(EINVAL);
+            }
+        }
+
+        if (is_grid)
+            sctx->nb_inputs = sctx->nb_grid_rows * sctx->nb_grid_columns;
+
+        if (strcmp(sctx->fillcolor_str, "none") &&
+            av_parse_color(sctx->fillcolor, sctx->fillcolor_str, -1, avctx) >= 0) {
+            sctx->fillcolor_enable = 1;
+        } else {
+            sctx->fillcolor_enable = 0;
+        }
+    }
+
+    for (int i = 0; i < sctx->nb_inputs; i++) {
+        AVFilterPad pad = { 0 };
+
+        pad.type = AVMEDIA_TYPE_VIDEO;
+        pad.name = av_asprintf("input%d", i);
+
+        if (!pad.name)
+            return AVERROR(ENOMEM);
+
+        if ((ret = ff_append_inpad_free_name(avctx, &pad)) < 0)
+            return ret;
+    }
+
+    sctx->regions = av_calloc(sctx->nb_inputs, sizeof(*sctx->regions));
+    if (!sctx->regions)
+        return AVERROR(ENOMEM);
+
+    return 0;
+}
+
+static av_cold void stack_uninit(AVFilterContext *avctx)
+{
+    StackBaseContext *sctx = avctx->priv;
+
+    av_freep(&sctx->regions);
+    ff_framesync_uninit(&sctx->fs);
+}
+
+static int stack_activate(AVFilterContext *avctx)
+{
+    StackBaseContext *sctx = avctx->priv;
+    return ff_framesync_activate(&sctx->fs);
+}
+
+static const AVFilterPad stack_outputs[] = {
+    {
+        .name          = "default",
+        .type          = AVMEDIA_TYPE_VIDEO,
+        .config_props  = config_output,
+    },
+};
+
+#define STACK_COMMON_OPTS                                               \
+    { "inputs", "Set number of inputs", OFFSET(base.nb_inputs), AV_OPT_TYPE_INT, { .i64 = 2 }, 2, UINT16_MAX, .flags = FLAGS }, \
+    { "shortest", "Force termination when the shortest input terminates", OFFSET(base.shortest), AV_OPT_TYPE_BOOL, { .i64 = 0 }, 0, 1, FLAGS },
+
+#define DEFINE_HSTACK_OPTIONS(api)                                      \
+    static const AVOption hstack_##api##_options[] = {                  \
+        STACK_COMMON_OPTS                                               \
+        { "height", "Set output height (0 to use the height of input 0)", OFFSET(base.tile_height), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, UINT16_MAX, FLAGS }, \
+        { NULL }                                                        \
+    }
+
+#define DEFINE_VSTACK_OPTIONS(api)                                      \
+    static const AVOption vstack_##api##_options[] = {                  \
+        STACK_COMMON_OPTS                                               \
+        { "width",   "Set output width (0 to use the width of input 0)", OFFSET(base.tile_width), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, UINT16_MAX, FLAGS }, \
+        { NULL }                                                        \
+    }
+
+#define DEFINE_XSTACK_OPTIONS(api)                                      \
+    static const AVOption xstack_##api##_options[] = {                  \
+        STACK_COMMON_OPTS                                               \
+        { "layout", "Set custom layout", OFFSET(base.layout), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, .flags = FLAGS }, \
+        { "grid",   "set fixed size grid layout", OFFSET(base.nb_grid_columns), AV_OPT_TYPE_IMAGE_SIZE, {.str = NULL}, 0, 0, .flags = FLAGS }, \
+        { "grid_tile_size",   "set tile size in grid layout", OFFSET(base.tile_width), AV_OPT_TYPE_IMAGE_SIZE, {.str = NULL}, 0, 0, .flags = FLAGS }, \
+        { "fill",   "Set the color for unused pixels", OFFSET(base.fillcolor_str), AV_OPT_TYPE_STRING, {.str = "none"}, .flags = FLAGS }, \
+        { NULL }                                                        \
+    }
+
+#define DEFINE_STACK_FILTER(category, api, capi)                        \
+    static const AVClass category##_##api##_class = {                   \
+        .class_name = #category "_" #api,                               \
+        .item_name  = av_default_item_name,                             \
+        .option     = category##_##api##_options,                       \
+        .version    = LIBAVUTIL_VERSION_INT,                            \
+    };                                                                  \
+    const AVFilter ff_vf_##category##_##api = {                         \
+        .name           = #category "_" #api,                           \
+        .description    = NULL_IF_CONFIG_SMALL(#capi " " #category),    \
+        .priv_size      = sizeof(StackHWContext),                       \
+        .priv_class     = &category##_##api##_class,                    \
+        .init           = api##_stack_init,                             \
+        .uninit         = api##_stack_uninit,                           \
+        .activate       = stack_activate,                               \
+        FILTER_QUERY_FUNC(api##_stack_query_formats),                   \
+        FILTER_OUTPUTS(stack_outputs),                                  \
+        .flags_internal = FF_FILTER_FLAG_HWFRAME_AWARE,                 \
+        .flags          = AVFILTER_FLAG_DYNAMIC_INPUTS,                 \
+    }
diff --git a/libavfilter/stack_internal.h b/libavfilter/stack_internal.h
new file mode 100644
index 0000000000..2847fc620b
--- /dev/null
+++ b/libavfilter/stack_internal.h
@@ -0,0 +1,60 @@
+/*
+ * 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
+ */
+
+#ifndef AVFILTER_STACK_INTERNAL_H
+#define AVFILTER_STACK_INTERNAL_H
+
+enum {
+    STACK_H = 0,
+    STACK_V = 1,
+    STACK_X = 2
+};
+
+typedef struct StackItemRegion {
+    int x;
+    int y;
+    int width;
+    int height;
+} StackItemRegion;
+
+typedef struct StackBaseContext {
+    HWContext hwctx; /**< must be the first field */
+
+    FFFrameSync fs;
+    int mode;
+    uint8_t fillcolor[4];
+    int fillcolor_enable;
+    StackItemRegion *regions;
+
+    /* Options */
+    int nb_inputs;
+    int shortest;
+    int tile_width;
+    int tile_height;
+    int nb_grid_columns;
+    int nb_grid_rows;
+    char *layout;
+    char *fillcolor_str;
+} StackBaseContext;
+
+static int config_comm_output(AVFilterLink *outlink);
+static int stack_init(AVFilterContext *avctx);
+static av_cold void stack_uninit(AVFilterContext *avctx);
+static int stack_activate(AVFilterContext *avctx);
+
+#endif /* AVFILTER_STACK_INTERNAL_H */
\ No newline at end of file
diff --git a/libavfilter/vf_stack_vaapi.c b/libavfilter/vf_stack_vaapi.c
index 403fbb19eb..26dbe3f7aa 100644
--- a/libavfilter/vf_stack_vaapi.c
+++ b/libavfilter/vf_stack_vaapi.c
@@ -42,33 +42,17 @@
 #include "framesync.h"
 #include "vaapi_vpp.h"
 
-#define OFFSET(x) offsetof(StackVAAPIContext, x)
-#define FLAGS (AV_OPT_FLAG_VIDEO_PARAM | AV_OPT_FLAG_FILTERING_PARAM)
-
-enum {
-    STACK_VAAPI_H = 0,
-    STACK_VAAPI_V = 1,
-    STACK_VAAPI_X = 2
-};
+#define HSTACK_NAME             "hstack_vaapi"
+#define VSTACK_NAME             "vstack_vaapi"
+#define XSTACK_NAME             "xstack_vaapi"
+#define HWContext               VAAPIVPPContext
+#define StackHWContext          StackVAAPIContext
+#include "stack_internal.h"
 
 typedef struct StackVAAPIContext {
-    VAAPIVPPContext vppctx; /**< must be the first field */
+    StackBaseContext base;
 
-    FFFrameSync fs;
-    int mode;
     VARectangle *rects;
-    uint8_t fillcolor[4];
-    int fillcolor_enable;
-
-    /* Options */
-    int nb_inputs;
-    int shortest;
-    int tile_width;
-    int tile_height;
-    int nb_grid_columns;
-    int nb_grid_rows;
-    char *layout;
-    char *fillcolor_str;
 } StackVAAPIContext;
 
 static int process_frame(FFFrameSync *fs)
@@ -122,14 +106,14 @@ static int process_frame(FFFrameSync *fs)
         params[i].surface = (VASurfaceID)(uintptr_t)iframe->data[3];
         params[i].output_region = &sctx->rects[i];
 
-        if (sctx->fillcolor_enable)
-            params[i].output_background_color = (sctx->fillcolor[3] << 24 |
-                                                 sctx->fillcolor[0] << 16 |
-                                                 sctx->fillcolor[1] << 8 |
-                                                 sctx->fillcolor[2]);
+        if (sctx->base.fillcolor_enable)
+            params[i].output_background_color = (sctx->base.fillcolor[3] << 24 |
+                                                 sctx->base.fillcolor[0] << 16 |
+                                                 sctx->base.fillcolor[1] << 8 |
+                                                 sctx->base.fillcolor[2]);
     }
 
-    oframe->pts = av_rescale_q(sctx->fs.pts, sctx->fs.time_base, outlink->time_base);
+    oframe->pts = av_rescale_q(sctx->base.fs.pts, sctx->base.fs.time_base, outlink->time_base);
     oframe->sample_aspect_ratio = outlink->sample_aspect_ratio;
 
     ret = ff_vaapi_vpp_render_pictures(avctx, params, avctx->nb_inputs, oframe);
@@ -147,37 +131,6 @@ fail:
     return ret;
 }
 
-static int init_framesync(AVFilterContext *avctx)
-{
-    StackVAAPIContext *sctx = avctx->priv;
-    int ret;
-
-    ret = ff_framesync_init(&sctx->fs, avctx, avctx->nb_inputs);
-    if (ret < 0)
-        return ret;
-
-    sctx->fs.on_event = process_frame;
-    sctx->fs.opaque = sctx;
-
-    for (int i = 0; i < sctx->nb_inputs; i++) {
-        FFFrameSyncIn *in = &sctx->fs.in[i];
-
-        in->before = EXT_STOP;
-        in->after = sctx->shortest ? EXT_STOP : EXT_INFINITY;
-        in->sync = 1;
-        in->time_base = avctx->inputs[i]->time_base;
-    }
-
-    return ff_framesync_configure(&sctx->fs);
-}
-
-#define SET_INPUT_REGION(rect, rx, ry, rw, rh) do {     \
-        rect->x = rx;                                   \
-        rect->y = ry;                                   \
-        rect->width = rw;                               \
-        rect->height = rh;                              \
-    } while (0)
-
 static int config_output(AVFilterLink *outlink)
 {
     AVFilterContext *avctx = outlink->src;
@@ -185,7 +138,7 @@ static int config_output(AVFilterLink *outlink)
     VAAPIVPPContext *vppctx = avctx->priv;
     AVFilterLink *inlink0 = avctx->inputs[0];
     AVHWFramesContext *hwfc0 = NULL;
-    int width, height, ret;
+    int ret;
 
     if (inlink0->format != AV_PIX_FMT_VAAPI || !inlink0->hw_frames_ctx || !inlink0->hw_frames_ctx->data) {
         av_log(avctx, AV_LOG_ERROR, "Software pixel format is not supported.\n");
@@ -194,7 +147,7 @@ static int config_output(AVFilterLink *outlink)
 
     hwfc0 = (AVHWFramesContext *)inlink0->hw_frames_ctx->data;
 
-    for (int i = 1; i < sctx->nb_inputs; i++) {
+    for (int i = 1; i < sctx->base.nb_inputs; i++) {
         AVFilterLink *inlink = avctx->inputs[i];
         AVHWFramesContext *hwfc = NULL;
 
@@ -219,168 +172,19 @@ static int config_output(AVFilterLink *outlink)
     ff_vaapi_vpp_config_input(inlink0);
     vppctx->output_format = hwfc0->sw_format;
 
-    if (sctx->mode == STACK_VAAPI_H) {
-        height = sctx->tile_height;
-        width = 0;
-
-        if (!height)
-            height = inlink0->h;
-
-        for (int i = 0; i < sctx->nb_inputs; i++) {
-            AVFilterLink *inlink = avctx->inputs[i];
-            VARectangle *rect = &sctx->rects[i];
-
-            SET_INPUT_REGION(rect, width, 0, av_rescale(height, inlink->w, inlink->h), height);
-            width += av_rescale(height, inlink->w, inlink->h);
-        }
-    } else if (sctx->mode == STACK_VAAPI_V) {
-        height = 0;
-        width = sctx->tile_width;
-
-        if (!width)
-            width = inlink0->w;
-
-        for (int i = 0; i < sctx->nb_inputs; i++) {
-            AVFilterLink *inlink = avctx->inputs[i];
-            VARectangle *rect = &sctx->rects[i];
-
-            SET_INPUT_REGION(rect, 0, height, width, av_rescale(width, inlink->h, inlink->w));
-            height += av_rescale(width, inlink->h, inlink->w);
-        }
-    } else if (sctx->nb_grid_rows && sctx->nb_grid_columns) {
-        int xpos = 0, ypos = 0;
-        int ow, oh, k = 0;
-
-        ow = sctx->tile_width;
-        oh = sctx->tile_height;
-
-        if (!ow || !oh) {
-            ow = avctx->inputs[0]->w;
-            oh = avctx->inputs[0]->h;
-        }
-
-        for (int i = 0; i < sctx->nb_grid_columns; i++) {
-            ypos = 0;
-
-            for (int j = 0; j < sctx->nb_grid_rows; j++) {
-                VARectangle *rect = &sctx->rects[k++];
-
-                SET_INPUT_REGION(rect, xpos, ypos, ow, oh);
-                ypos += oh;
-            }
-
-            xpos += ow;
-        }
-
-        width = ow * sctx->nb_grid_columns;
-        height = oh * sctx->nb_grid_rows;
-    } else {
-        char *arg, *p = sctx->layout, *saveptr = NULL;
-        char *arg2, *p2, *saveptr2 = NULL;
-        char *arg3, *p3, *saveptr3 = NULL;
-        int xpos, ypos, size;
-        int ow, oh;
-
-        width = avctx->inputs[0]->w;
-        height = avctx->inputs[0]->h;
-
-        for (int i = 0; i < sctx->nb_inputs; i++) {
-            AVFilterLink *inlink = avctx->inputs[i];
-            VARectangle *rect = &sctx->rects[i];
-
-            ow = inlink->w;
-            oh = inlink->h;
-
-            if (!(arg = av_strtok(p, "|", &saveptr)))
-                return AVERROR(EINVAL);
-
-            p = NULL;
-            p2 = arg;
-            xpos = ypos = 0;
-
-            for (int j = 0; j < 3; j++) {
-                if (!(arg2 = av_strtok(p2, "_", &saveptr2))) {
-                    if (j == 2)
-                        break;
-                    else
-                        return AVERROR(EINVAL);
-                }
-
-                p2 = NULL;
-                p3 = arg2;
-
-                if (j == 2) {
-                    if ((ret = av_parse_video_size(&ow, &oh, p3)) < 0) {
-                        av_log(avctx, AV_LOG_ERROR, "Invalid size '%s'\n", p3);
-                        return ret;
-                    }
-
-                    break;
-                }
-
-                while ((arg3 = av_strtok(p3, "+", &saveptr3))) {
-                    p3 = NULL;
-                    if (sscanf(arg3, "w%d", &size) == 1) {
-                        if (size == i || size < 0 || size >= sctx->nb_inputs)
-                            return AVERROR(EINVAL);
-
-                        if (!j)
-                            xpos += sctx->rects[size].width;
-                        else
-                            ypos += sctx->rects[size].width;
-                    } else if (sscanf(arg3, "h%d", &size) == 1) {
-                        if (size == i || size < 0 || size >= sctx->nb_inputs)
-                            return AVERROR(EINVAL);
-
-                        if (!j)
-                            xpos += sctx->rects[size].height;
-                        else
-                            ypos += sctx->rects[size].height;
-                    } else if (sscanf(arg3, "%d", &size) == 1) {
-                        if (size < 0)
-                            return AVERROR(EINVAL);
-
-                        if (!j)
-                            xpos += size;
-                        else
-                            ypos += size;
-                    } else {
-                        return AVERROR(EINVAL);
-                    }
-                }
-            }
-
-            SET_INPUT_REGION(rect, xpos, ypos, ow, oh);
-            width = FFMAX(width,  xpos + ow);
-            height = FFMAX(height, ypos + oh);
-        }
-
-    }
-
-    outlink->w = width;
-    outlink->h = height;
-    outlink->frame_rate = inlink0->frame_rate;
-    outlink->sample_aspect_ratio = inlink0->sample_aspect_ratio;
-
-    for (int i = 1; i < sctx->nb_inputs; i++) {
-        AVFilterLink *inlink = avctx->inputs[i];
-        if (outlink->frame_rate.num != inlink->frame_rate.num ||
-            outlink->frame_rate.den != inlink->frame_rate.den) {
-            av_log(avctx, AV_LOG_VERBOSE,
-                    "Video inputs have different frame rates, output will be VFR\n");
-            outlink->frame_rate = av_make_q(1, 0);
-            break;
-        }
-    }
-
-    ret = init_framesync(avctx);
+    ret = config_comm_output(outlink);
     if (ret < 0)
         return ret;
 
-    outlink->time_base = sctx->fs.time_base;
+    for (int i = 0; i < sctx->base.nb_inputs; i++) {
+        sctx->rects[i].x = sctx->base.regions[i].x;
+        sctx->rects[i].y = sctx->base.regions[i].y;
+        sctx->rects[i].width = sctx->base.regions[i].width;
+        sctx->rects[i].height = sctx->base.regions[i].height;
+    }
 
-    vppctx->output_width = width;
-    vppctx->output_height = height;
+    vppctx->output_width = outlink->w;
+    vppctx->output_height = outlink->h;
 
     return ff_vaapi_vpp_config_output(outlink);
 }
@@ -391,59 +195,12 @@ static int vaapi_stack_init(AVFilterContext *avctx)
     VAAPIVPPContext *vppctx = avctx->priv;
     int ret;
 
-    if (!strcmp(avctx->filter->name, "hstack_vaapi"))
-        sctx->mode = STACK_VAAPI_H;
-    else if (!strcmp(avctx->filter->name, "vstack_vaapi"))
-        sctx->mode = STACK_VAAPI_V;
-    else {
-        int is_grid;
-
-        av_assert0(strcmp(avctx->filter->name, "xstack_vaapi") == 0);
-        sctx->mode = STACK_VAAPI_X;
-        is_grid = sctx->nb_grid_rows && sctx->nb_grid_columns;
-
-        if (sctx->layout && is_grid) {
-            av_log(avctx, AV_LOG_ERROR, "Both layout and grid were specified. Only one is allowed.\n");
-            return AVERROR(EINVAL);
-        }
-
-        if (!sctx->layout && !is_grid) {
-            if (sctx->nb_inputs == 2) {
-                sctx->nb_grid_rows = 1;
-                sctx->nb_grid_columns = 2;
-                is_grid = 1;
-            } else {
-                av_log(avctx, AV_LOG_ERROR, "No layout or grid specified.\n");
-                return AVERROR(EINVAL);
-            }
-        }
-
-        if (is_grid)
-            sctx->nb_inputs = sctx->nb_grid_rows * sctx->nb_grid_columns;
-
-        if (strcmp(sctx->fillcolor_str, "none") &&
-            av_parse_color(sctx->fillcolor, sctx->fillcolor_str, -1, avctx) >= 0) {
-            sctx->fillcolor_enable = 1;
-        } else {
-            sctx->fillcolor_enable = 0;
-        }
-    }
-
-    for (int i = 0; i < sctx->nb_inputs; i++) {
-        AVFilterPad pad = { 0 };
-
-        pad.type = AVMEDIA_TYPE_VIDEO;
-        pad.name = av_asprintf("input%d", i);
-
-        if (!pad.name)
-            return AVERROR(ENOMEM);
-
-        if ((ret = ff_append_inpad_free_name(avctx, &pad)) < 0)
-            return ret;
-    }
+    ret = stack_init(avctx);
+    if (ret)
+        return ret;
 
     /* stack region */
-    sctx->rects = av_calloc(sctx->nb_inputs, sizeof(*sctx->rects));
+    sctx->rects = av_calloc(sctx->base.nb_inputs, sizeof(*sctx->rects));
     if (!sctx->rects)
         return AVERROR(ENOMEM);
 
@@ -457,14 +214,9 @@ static av_cold void vaapi_stack_uninit(AVFilterContext *avctx)
 {
     StackVAAPIContext *sctx = avctx->priv;
 
-    ff_framesync_uninit(&sctx->fs);
-    av_freep(&sctx->rects);
-}
+    stack_uninit(avctx);
 
-static int vaapi_stack_activate(AVFilterContext *avctx)
-{
-    StackVAAPIContext *sctx = avctx->priv;
-    return ff_framesync_activate(&sctx->fs);
+    av_freep(&sctx->rects);
 }
 
 static int vaapi_stack_query_formats(AVFilterContext *avctx)
@@ -477,98 +229,25 @@ static int vaapi_stack_query_formats(AVFilterContext *avctx)
     return ff_set_common_formats_from_list(avctx, pixel_formats);
 }
 
-static const AVFilterPad vaapi_stack_outputs[] = {
-    {
-        .name          = "default",
-        .type          = AVMEDIA_TYPE_VIDEO,
-        .config_props  = config_output,
-    },
-};
-
-#define STACK_COMMON_OPTS \
-    { "inputs", "Set number of inputs", OFFSET(nb_inputs), AV_OPT_TYPE_INT, { .i64 = 2 }, 2, UINT16_MAX, .flags = FLAGS },                   \
-    { "shortest", "Force termination when the shortest input terminates", OFFSET(shortest), AV_OPT_TYPE_BOOL, { .i64 = 0 }, 0, 1, FLAGS },
+#include "stack_internal.c"
 
 #if CONFIG_HSTACK_VAAPI_FILTER
 
-static const AVOption hstack_vaapi_options[] = {
-    STACK_COMMON_OPTS
-
-    { "height", "Set output height (0 to use the height of input 0)", OFFSET(tile_height), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, UINT16_MAX, FLAGS },
-    { NULL }
-};
-
-AVFILTER_DEFINE_CLASS(hstack_vaapi);
-
-const AVFilter ff_vf_hstack_vaapi = {
-    .name           = "hstack_vaapi",
-    .description    = NULL_IF_CONFIG_SMALL("VA-API hstack."),
-    .priv_size      = sizeof(StackVAAPIContext),
-    .priv_class     = &hstack_vaapi_class,
-    .init           = vaapi_stack_init,
-    .uninit         = vaapi_stack_uninit,
-    .activate       = vaapi_stack_activate,
-    FILTER_QUERY_FUNC(vaapi_stack_query_formats),
-    FILTER_OUTPUTS(vaapi_stack_outputs),
-    .flags_internal = FF_FILTER_FLAG_HWFRAME_AWARE,
-    .flags          = AVFILTER_FLAG_DYNAMIC_INPUTS,
-};
+DEFINE_HSTACK_OPTIONS(vaapi);
+DEFINE_STACK_FILTER(hstack, vaapi, "VA-API");
 
 #endif
 
 #if CONFIG_VSTACK_VAAPI_FILTER
 
-static const AVOption vstack_vaapi_options[] = {
-    STACK_COMMON_OPTS
-
-    { "width",   "Set output width (0 to use the width of input 0)", OFFSET(tile_width), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, UINT16_MAX, FLAGS },
-    { NULL }
-};
-
-AVFILTER_DEFINE_CLASS(vstack_vaapi);
-
-const AVFilter ff_vf_vstack_vaapi = {
-    .name           = "vstack_vaapi",
-    .description    = NULL_IF_CONFIG_SMALL("VA-API vstack."),
-    .priv_size      = sizeof(StackVAAPIContext),
-    .priv_class     = &vstack_vaapi_class,
-    .init           = vaapi_stack_init,
-    .uninit         = vaapi_stack_uninit,
-    .activate       = vaapi_stack_activate,
-    FILTER_QUERY_FUNC(vaapi_stack_query_formats),
-    FILTER_OUTPUTS(vaapi_stack_outputs),
-    .flags_internal = FF_FILTER_FLAG_HWFRAME_AWARE,
-    .flags          = AVFILTER_FLAG_DYNAMIC_INPUTS,
-};
+DEFINE_VSTACK_OPTIONS(vaapi);
+DEFINE_STACK_FILTER(vstack, vaapi, "VA-API");
 
 #endif
 
 #if CONFIG_XSTACK_VAAPI_FILTER
 
-static const AVOption xstack_vaapi_options[] = {
-    STACK_COMMON_OPTS
-
-    { "layout", "Set custom layout", OFFSET(layout), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, .flags = FLAGS },
-    { "grid",   "set fixed size grid layout", OFFSET(nb_grid_columns), AV_OPT_TYPE_IMAGE_SIZE, {.str = NULL}, 0, 0, .flags = FLAGS },
-    { "grid_tile_size",   "set tile size in grid layout", OFFSET(tile_width), AV_OPT_TYPE_IMAGE_SIZE, {.str = NULL}, 0, 0, .flags = FLAGS },
-    { "fill",   "Set the color for unused pixels", OFFSET(fillcolor_str), AV_OPT_TYPE_STRING, {.str = "none"}, .flags = FLAGS },
-    { NULL }
-};
-
-AVFILTER_DEFINE_CLASS(xstack_vaapi);
-
-const AVFilter ff_vf_xstack_vaapi = {
-    .name           = "xstack_vaapi",
-    .description    = NULL_IF_CONFIG_SMALL("VA-API xstack."),
-    .priv_size      = sizeof(StackVAAPIContext),
-    .priv_class     = &xstack_vaapi_class,
-    .init           = vaapi_stack_init,
-    .uninit         = vaapi_stack_uninit,
-    .activate       = vaapi_stack_activate,
-    FILTER_OUTPUTS(vaapi_stack_outputs),
-    FILTER_QUERY_FUNC(vaapi_stack_query_formats),
-    .flags_internal = FF_FILTER_FLAG_HWFRAME_AWARE,
-    .flags          = AVFILTER_FLAG_DYNAMIC_INPUTS,
-};
+DEFINE_XSTACK_OPTIONS(vaapi);
+DEFINE_STACK_FILTER(xstack, vaapi, "VA-API");
 
 #endif
