[FFmpeg-devel] avfilter: add scroll video filter

Submitted by Paul B Mahol on Sept. 29, 2019, 12:56 p.m.

Details

Message ID 20190929125625.30153-1-onemda@gmail.com
State New
Headers show

Commit Message

Paul B Mahol Sept. 29, 2019, 12:56 p.m.
Signed-off-by: Paul B Mahol <onemda@gmail.com>
---
 doc/filters.texi         |  20 ++++
 libavfilter/Makefile     |   1 +
 libavfilter/allfilters.c |   1 +
 libavfilter/vf_scroll.c  | 200 +++++++++++++++++++++++++++++++++++++++
 4 files changed, 222 insertions(+)
 create mode 100644 libavfilter/vf_scroll.c

Comments

Paul B Mahol Sept. 30, 2019, 5:14 p.m.
will apply.

On 9/29/19, Paul B Mahol <onemda@gmail.com> wrote:
> Signed-off-by: Paul B Mahol <onemda@gmail.com>
> ---
>  doc/filters.texi         |  20 ++++
>  libavfilter/Makefile     |   1 +
>  libavfilter/allfilters.c |   1 +
>  libavfilter/vf_scroll.c  | 200 +++++++++++++++++++++++++++++++++++++++
>  4 files changed, 222 insertions(+)
>  create mode 100644 libavfilter/vf_scroll.c
>
> diff --git a/doc/filters.texi b/doc/filters.texi
> index 333f502083..416bb327c1 100644
> --- a/doc/filters.texi
> +++ b/doc/filters.texi
> @@ -15650,6 +15650,26 @@ Scale a logo to 1/10th the height of a video, while
> preserving its display aspec
>  @end example
>  @end itemize
>
> +@section scroll
> +Scroll input video horizontally and/or vertically by constant speed.
> +
> +The filter accepts the following options:
> +@table @option
> +@item horizontal, h
> +Set the horizontal scrolling speed. Default is 0. Allowed range is from -1
> to 1.
> +Negative values changes scrolling direction.
> +
> +@item vertical, v
> +Set the vertical scrolling speed. Default is 0. Allowed range is from -1 to
> 1.
> +Negative values changes scrolling direction.
> +
> +@item hpos
> +Set the initial horizontal scrolling position. Default is 0. Allowed range
> is from 0 to 1.
> +
> +@item vpos
> +Set the initial vertical scrolling position. Default is 0. Allowed range is
> from 0 to 1.
> +@end table
> +
>  @anchor{selectivecolor}
>  @section selectivecolor
>
> diff --git a/libavfilter/Makefile b/libavfilter/Makefile
> index b99ecc8c26..124a3496e6 100644
> --- a/libavfilter/Makefile
> +++ b/libavfilter/Makefile
> @@ -356,6 +356,7 @@ OBJS-$(CONFIG_SCALE_NPP_FILTER)              +=
> vf_scale_npp.o scale.o
>  OBJS-$(CONFIG_SCALE_QSV_FILTER)              += vf_scale_qsv.o
>  OBJS-$(CONFIG_SCALE_VAAPI_FILTER)            += vf_scale_vaapi.o scale.o
> vaapi_vpp.o
>  OBJS-$(CONFIG_SCALE2REF_FILTER)              += vf_scale.o scale.o
> +OBJS-$(CONFIG_SCROLL_FILTER)                 += vf_scroll.o
>  OBJS-$(CONFIG_SELECT_FILTER)                 += f_select.o
>  OBJS-$(CONFIG_SELECTIVECOLOR_FILTER)         += vf_selectivecolor.o
>  OBJS-$(CONFIG_SENDCMD_FILTER)                += f_sendcmd.o
> diff --git a/libavfilter/allfilters.c b/libavfilter/allfilters.c
> index 788652ab1e..0408bcd3df 100644
> --- a/libavfilter/allfilters.c
> +++ b/libavfilter/allfilters.c
> @@ -338,6 +338,7 @@ extern AVFilter ff_vf_scale_npp;
>  extern AVFilter ff_vf_scale_qsv;
>  extern AVFilter ff_vf_scale_vaapi;
>  extern AVFilter ff_vf_scale2ref;
> +extern AVFilter ff_vf_scroll;
>  extern AVFilter ff_vf_select;
>  extern AVFilter ff_vf_selectivecolor;
>  extern AVFilter ff_vf_sendcmd;
> diff --git a/libavfilter/vf_scroll.c b/libavfilter/vf_scroll.c
> new file mode 100644
> index 0000000000..36db39f2ac
> --- /dev/null
> +++ b/libavfilter/vf_scroll.c
> @@ -0,0 +1,200 @@
> +/*
> + * Copyright (c) 2019 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/colorspace.h"
> +#include "libavutil/common.h"
> +#include "libavutil/opt.h"
> +#include "libavutil/pixdesc.h"
> +#include "avfilter.h"
> +#include "drawutils.h"
> +#include "formats.h"
> +#include "internal.h"
> +#include "video.h"
> +
> +typedef struct ScrollContext {
> +    const AVClass *class;
> +
> +    float h_speed, v_speed;
> +    float h_pos, v_pos;
> +    float h_ipos, v_ipos;
> +
> +    const AVPixFmtDescriptor *desc;
> +    int nb_planes;
> +    int bytes;
> +
> +    int planewidth[4];
> +    int planeheight[4];
> +} ScrollContext;
> +
> +static int query_formats(AVFilterContext *ctx)
> +{
> +    static const enum AVPixelFormat pix_fmts[] = {
> +        AV_PIX_FMT_YUVA444P, AV_PIX_FMT_YUV444P, AV_PIX_FMT_YUV440P,
> +        AV_PIX_FMT_YUVJ444P, AV_PIX_FMT_YUVJ440P,
> +        AV_PIX_FMT_YUVA422P, AV_PIX_FMT_YUV422P, AV_PIX_FMT_YUVA420P,
> AV_PIX_FMT_YUV420P,
> +        AV_PIX_FMT_YUVJ422P, AV_PIX_FMT_YUVJ420P,
> +        AV_PIX_FMT_YUVJ411P, AV_PIX_FMT_YUV411P, AV_PIX_FMT_YUV410P,
> +        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_YUV420P12, AV_PIX_FMT_YUV422P12, AV_PIX_FMT_YUV444P12,
> AV_PIX_FMT_YUV440P12,
> +        AV_PIX_FMT_YUV420P14, AV_PIX_FMT_YUV422P14, AV_PIX_FMT_YUV444P14,
> +        AV_PIX_FMT_YUV420P16, AV_PIX_FMT_YUV422P16, AV_PIX_FMT_YUV444P16,
> +        AV_PIX_FMT_YUVA420P9, AV_PIX_FMT_YUVA422P9, AV_PIX_FMT_YUVA444P9,
> +        AV_PIX_FMT_YUVA420P10, AV_PIX_FMT_YUVA422P10,
> AV_PIX_FMT_YUVA444P10,
> +        AV_PIX_FMT_YUVA420P16, AV_PIX_FMT_YUVA422P16,
> AV_PIX_FMT_YUVA444P16,
> +        AV_PIX_FMT_GBRP, AV_PIX_FMT_GBRP9, AV_PIX_FMT_GBRP10,
> +        AV_PIX_FMT_GBRP12, AV_PIX_FMT_GBRP14, AV_PIX_FMT_GBRP16,
> +        AV_PIX_FMT_GBRAP, AV_PIX_FMT_GBRAP10, AV_PIX_FMT_GBRAP12,
> AV_PIX_FMT_GBRAP16,
> +        AV_PIX_FMT_GRAY8, AV_PIX_FMT_GRAY9, AV_PIX_FMT_GRAY10,
> AV_PIX_FMT_GRAY12, AV_PIX_FMT_GRAY14, AV_PIX_FMT_GRAY16,
> +        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 scroll(ScrollContext *s, AVFrame *in, AVFrame *out)
> +{
> +    int h_pos, v_pos;
> +    int pos_h[4], pos_v[4];
> +
> +    s->h_pos += s->h_speed * in->width;
> +    s->v_pos += s->v_speed * in->height;
> +
> +    s->h_pos = fmodf(s->h_pos, in->width);
> +    s->v_pos = fmodf(s->v_pos, in->height);
> +
> +    h_pos = s->h_pos;
> +    v_pos = s->v_pos;
> +
> +    if (h_pos < 0)
> +        h_pos += in->width;
> +    if (v_pos < 0)
> +        v_pos += in->height;
> +
> +    pos_v[1] = pos_v[2] = AV_CEIL_RSHIFT(v_pos, s->desc->log2_chroma_h);
> +    pos_v[0] = pos_v[3] = v_pos;
> +    pos_h[1] = pos_h[2] = AV_CEIL_RSHIFT(h_pos, s->desc->log2_chroma_w) *
> s->bytes;
> +    pos_h[0] = pos_h[3] = h_pos * s->bytes;
> +
> +    for (int p = 0; p < s->nb_planes; p++) {
> +        const uint8_t *src = in->data[p];
> +        uint8_t *dst = out->data[p];
> +        const int h = s->planeheight[p];
> +        const int w = s->planewidth[p] * s->bytes;
> +
> +        for (int y = 0; y < h; y++) {
> +            int yy = (y + pos_v[p]) % h;
> +            const uint8_t *ssrc = src + yy * in->linesize[p];
> +
> +            memcpy(dst, ssrc + pos_h[p], w - pos_h[p]);
> +            if (pos_h[p])
> +                memcpy(dst + w - pos_h[p], ssrc, pos_h[p]);
> +
> +            dst += out->linesize[p];
> +        }
> +    }
> +}
> +
> +static int filter_frame(AVFilterLink *inlink, AVFrame *in)
> +{
> +    AVFilterContext *ctx = inlink->dst;
> +    ScrollContext *s = ctx->priv;
> +    AVFilterLink *outlink = ctx->outputs[0];
> +    AVFrame *out;
> +
> +    out = ff_get_video_buffer(outlink, outlink->w, outlink->h);
> +    if (!out) {
> +        av_frame_free(&in);
> +        return AVERROR(ENOMEM);
> +    }
> +    av_frame_copy_props(out, in);
> +
> +    scroll(s, in, out);
> +
> +    av_frame_free(&in);
> +    return ff_filter_frame(outlink, out);
> +}
> +
> +static int config_input(AVFilterLink *inlink)
> +{
> +    AVFilterContext *ctx = inlink->dst;
> +    ScrollContext *s = ctx->priv;
> +
> +    s->desc = av_pix_fmt_desc_get(inlink->format);
> +    s->nb_planes = s->desc->nb_components;
> +    s->bytes = (s->desc->comp[0].depth + 7) >> 3;
> +
> +    s->planeheight[1] = s->planeheight[2] = AV_CEIL_RSHIFT(inlink->h,
> s->desc->log2_chroma_h);
> +    s->planeheight[0] = s->planeheight[3] = inlink->h;
> +    s->planewidth[1]  = s->planewidth[2]  = AV_CEIL_RSHIFT(inlink->w,
> s->desc->log2_chroma_w);
> +    s->planewidth[0]  = s->planewidth[3]  = inlink->w;
> +
> +    s->h_pos += s->h_ipos * inlink->w;
> +    s->v_pos += s->v_ipos * inlink->h;
> +
> +    return 0;
> +}
> +
> +#define OFFSET(x) offsetof(ScrollContext, x)
> +#define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
> +
> +static const AVOption scroll_options[] = {
> +    { "horizontal", "set the horizontal scrolling speed", OFFSET(h_speed),
> AV_OPT_TYPE_FLOAT, {.dbl=0.}, -1., 1., FLAGS },
> +    { "h",          "set the horizontal scrolling speed", OFFSET(h_speed),
> AV_OPT_TYPE_FLOAT, {.dbl=0.}, -1., 1., FLAGS },
> +    { "vertical",   "set the vertical scrolling speed",   OFFSET(v_speed),
> AV_OPT_TYPE_FLOAT, {.dbl=0.}, -1., 1., FLAGS },
> +    { "v",          "set the vertical scrolling speed",   OFFSET(v_speed),
> AV_OPT_TYPE_FLOAT, {.dbl=0.}, -1., 1., FLAGS },
> +    { "hpos",       "set initial horizontal position",    OFFSET(h_ipos),
> AV_OPT_TYPE_FLOAT, {.dbl=0.},   0, 1., FLAGS },
> +    { "vpos",       "set initial vertical position",      OFFSET(v_ipos),
> AV_OPT_TYPE_FLOAT, {.dbl=0.},   0, 1., FLAGS },
> +    { NULL }
> +};
> +
> +AVFILTER_DEFINE_CLASS(scroll);
> +
> +static const AVFilterPad scroll_inputs[] = {
> +    {
> +        .name           = "default",
> +        .type           = AVMEDIA_TYPE_VIDEO,
> +        .config_props   = config_input,
> +        .filter_frame   = filter_frame,
> +    },
> +    { NULL }
> +};
> +
> +static const AVFilterPad scroll_outputs[] = {
> +    {
> +        .name = "default",
> +        .type = AVMEDIA_TYPE_VIDEO,
> +    },
> +    { NULL }
> +};
> +
> +AVFilter ff_vf_scroll = {
> +    .name          = "scroll",
> +    .description   = NULL_IF_CONFIG_SMALL("Scroll input video."),
> +    .priv_size     = sizeof(ScrollContext),
> +    .priv_class    = &scroll_class,
> +    .query_formats = query_formats,
> +    .inputs        = scroll_inputs,
> +    .outputs       = scroll_outputs,
> +    .flags         = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC,
> +};
> --
> 2.17.1
>
>

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diff --git a/doc/filters.texi b/doc/filters.texi
index 333f502083..416bb327c1 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -15650,6 +15650,26 @@  Scale a logo to 1/10th the height of a video, while preserving its display aspec
 @end example
 @end itemize
 
+@section scroll
+Scroll input video horizontally and/or vertically by constant speed.
+
+The filter accepts the following options:
+@table @option
+@item horizontal, h
+Set the horizontal scrolling speed. Default is 0. Allowed range is from -1 to 1.
+Negative values changes scrolling direction.
+
+@item vertical, v
+Set the vertical scrolling speed. Default is 0. Allowed range is from -1 to 1.
+Negative values changes scrolling direction.
+
+@item hpos
+Set the initial horizontal scrolling position. Default is 0. Allowed range is from 0 to 1.
+
+@item vpos
+Set the initial vertical scrolling position. Default is 0. Allowed range is from 0 to 1.
+@end table
+
 @anchor{selectivecolor}
 @section selectivecolor
 
diff --git a/libavfilter/Makefile b/libavfilter/Makefile
index b99ecc8c26..124a3496e6 100644
--- a/libavfilter/Makefile
+++ b/libavfilter/Makefile
@@ -356,6 +356,7 @@  OBJS-$(CONFIG_SCALE_NPP_FILTER)              += vf_scale_npp.o scale.o
 OBJS-$(CONFIG_SCALE_QSV_FILTER)              += vf_scale_qsv.o
 OBJS-$(CONFIG_SCALE_VAAPI_FILTER)            += vf_scale_vaapi.o scale.o vaapi_vpp.o
 OBJS-$(CONFIG_SCALE2REF_FILTER)              += vf_scale.o scale.o
+OBJS-$(CONFIG_SCROLL_FILTER)                 += vf_scroll.o
 OBJS-$(CONFIG_SELECT_FILTER)                 += f_select.o
 OBJS-$(CONFIG_SELECTIVECOLOR_FILTER)         += vf_selectivecolor.o
 OBJS-$(CONFIG_SENDCMD_FILTER)                += f_sendcmd.o
diff --git a/libavfilter/allfilters.c b/libavfilter/allfilters.c
index 788652ab1e..0408bcd3df 100644
--- a/libavfilter/allfilters.c
+++ b/libavfilter/allfilters.c
@@ -338,6 +338,7 @@  extern AVFilter ff_vf_scale_npp;
 extern AVFilter ff_vf_scale_qsv;
 extern AVFilter ff_vf_scale_vaapi;
 extern AVFilter ff_vf_scale2ref;
+extern AVFilter ff_vf_scroll;
 extern AVFilter ff_vf_select;
 extern AVFilter ff_vf_selectivecolor;
 extern AVFilter ff_vf_sendcmd;
diff --git a/libavfilter/vf_scroll.c b/libavfilter/vf_scroll.c
new file mode 100644
index 0000000000..36db39f2ac
--- /dev/null
+++ b/libavfilter/vf_scroll.c
@@ -0,0 +1,200 @@ 
+/*
+ * Copyright (c) 2019 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/colorspace.h"
+#include "libavutil/common.h"
+#include "libavutil/opt.h"
+#include "libavutil/pixdesc.h"
+#include "avfilter.h"
+#include "drawutils.h"
+#include "formats.h"
+#include "internal.h"
+#include "video.h"
+
+typedef struct ScrollContext {
+    const AVClass *class;
+
+    float h_speed, v_speed;
+    float h_pos, v_pos;
+    float h_ipos, v_ipos;
+
+    const AVPixFmtDescriptor *desc;
+    int nb_planes;
+    int bytes;
+
+    int planewidth[4];
+    int planeheight[4];
+} ScrollContext;
+
+static int query_formats(AVFilterContext *ctx)
+{
+    static const enum AVPixelFormat pix_fmts[] = {
+        AV_PIX_FMT_YUVA444P, AV_PIX_FMT_YUV444P, AV_PIX_FMT_YUV440P,
+        AV_PIX_FMT_YUVJ444P, AV_PIX_FMT_YUVJ440P,
+        AV_PIX_FMT_YUVA422P, AV_PIX_FMT_YUV422P, AV_PIX_FMT_YUVA420P, AV_PIX_FMT_YUV420P,
+        AV_PIX_FMT_YUVJ422P, AV_PIX_FMT_YUVJ420P,
+        AV_PIX_FMT_YUVJ411P, AV_PIX_FMT_YUV411P, AV_PIX_FMT_YUV410P,
+        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_YUV420P12, AV_PIX_FMT_YUV422P12, AV_PIX_FMT_YUV444P12, AV_PIX_FMT_YUV440P12,
+        AV_PIX_FMT_YUV420P14, AV_PIX_FMT_YUV422P14, AV_PIX_FMT_YUV444P14,
+        AV_PIX_FMT_YUV420P16, AV_PIX_FMT_YUV422P16, AV_PIX_FMT_YUV444P16,
+        AV_PIX_FMT_YUVA420P9, AV_PIX_FMT_YUVA422P9, AV_PIX_FMT_YUVA444P9,
+        AV_PIX_FMT_YUVA420P10, AV_PIX_FMT_YUVA422P10, AV_PIX_FMT_YUVA444P10,
+        AV_PIX_FMT_YUVA420P16, AV_PIX_FMT_YUVA422P16, AV_PIX_FMT_YUVA444P16,
+        AV_PIX_FMT_GBRP, AV_PIX_FMT_GBRP9, AV_PIX_FMT_GBRP10,
+        AV_PIX_FMT_GBRP12, AV_PIX_FMT_GBRP14, AV_PIX_FMT_GBRP16,
+        AV_PIX_FMT_GBRAP, AV_PIX_FMT_GBRAP10, AV_PIX_FMT_GBRAP12, AV_PIX_FMT_GBRAP16,
+        AV_PIX_FMT_GRAY8, AV_PIX_FMT_GRAY9, AV_PIX_FMT_GRAY10, AV_PIX_FMT_GRAY12, AV_PIX_FMT_GRAY14, AV_PIX_FMT_GRAY16,
+        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 scroll(ScrollContext *s, AVFrame *in, AVFrame *out)
+{
+    int h_pos, v_pos;
+    int pos_h[4], pos_v[4];
+
+    s->h_pos += s->h_speed * in->width;
+    s->v_pos += s->v_speed * in->height;
+
+    s->h_pos = fmodf(s->h_pos, in->width);
+    s->v_pos = fmodf(s->v_pos, in->height);
+
+    h_pos = s->h_pos;
+    v_pos = s->v_pos;
+
+    if (h_pos < 0)
+        h_pos += in->width;
+    if (v_pos < 0)
+        v_pos += in->height;
+
+    pos_v[1] = pos_v[2] = AV_CEIL_RSHIFT(v_pos, s->desc->log2_chroma_h);
+    pos_v[0] = pos_v[3] = v_pos;
+    pos_h[1] = pos_h[2] = AV_CEIL_RSHIFT(h_pos, s->desc->log2_chroma_w) * s->bytes;
+    pos_h[0] = pos_h[3] = h_pos * s->bytes;
+
+    for (int p = 0; p < s->nb_planes; p++) {
+        const uint8_t *src = in->data[p];
+        uint8_t *dst = out->data[p];
+        const int h = s->planeheight[p];
+        const int w = s->planewidth[p] * s->bytes;
+
+        for (int y = 0; y < h; y++) {
+            int yy = (y + pos_v[p]) % h;
+            const uint8_t *ssrc = src + yy * in->linesize[p];
+
+            memcpy(dst, ssrc + pos_h[p], w - pos_h[p]);
+            if (pos_h[p])
+                memcpy(dst + w - pos_h[p], ssrc, pos_h[p]);
+
+            dst += out->linesize[p];
+        }
+    }
+}
+
+static int filter_frame(AVFilterLink *inlink, AVFrame *in)
+{
+    AVFilterContext *ctx = inlink->dst;
+    ScrollContext *s = ctx->priv;
+    AVFilterLink *outlink = ctx->outputs[0];
+    AVFrame *out;
+
+    out = ff_get_video_buffer(outlink, outlink->w, outlink->h);
+    if (!out) {
+        av_frame_free(&in);
+        return AVERROR(ENOMEM);
+    }
+    av_frame_copy_props(out, in);
+
+    scroll(s, in, out);
+
+    av_frame_free(&in);
+    return ff_filter_frame(outlink, out);
+}
+
+static int config_input(AVFilterLink *inlink)
+{
+    AVFilterContext *ctx = inlink->dst;
+    ScrollContext *s = ctx->priv;
+
+    s->desc = av_pix_fmt_desc_get(inlink->format);
+    s->nb_planes = s->desc->nb_components;
+    s->bytes = (s->desc->comp[0].depth + 7) >> 3;
+
+    s->planeheight[1] = s->planeheight[2] = AV_CEIL_RSHIFT(inlink->h, s->desc->log2_chroma_h);
+    s->planeheight[0] = s->planeheight[3] = inlink->h;
+    s->planewidth[1]  = s->planewidth[2]  = AV_CEIL_RSHIFT(inlink->w, s->desc->log2_chroma_w);
+    s->planewidth[0]  = s->planewidth[3]  = inlink->w;
+
+    s->h_pos += s->h_ipos * inlink->w;
+    s->v_pos += s->v_ipos * inlink->h;
+
+    return 0;
+}
+
+#define OFFSET(x) offsetof(ScrollContext, x)
+#define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
+
+static const AVOption scroll_options[] = {
+    { "horizontal", "set the horizontal scrolling speed", OFFSET(h_speed), AV_OPT_TYPE_FLOAT, {.dbl=0.}, -1., 1., FLAGS },
+    { "h",          "set the horizontal scrolling speed", OFFSET(h_speed), AV_OPT_TYPE_FLOAT, {.dbl=0.}, -1., 1., FLAGS },
+    { "vertical",   "set the vertical scrolling speed",   OFFSET(v_speed), AV_OPT_TYPE_FLOAT, {.dbl=0.}, -1., 1., FLAGS },
+    { "v",          "set the vertical scrolling speed",   OFFSET(v_speed), AV_OPT_TYPE_FLOAT, {.dbl=0.}, -1., 1., FLAGS },
+    { "hpos",       "set initial horizontal position",    OFFSET(h_ipos),  AV_OPT_TYPE_FLOAT, {.dbl=0.},   0, 1., FLAGS },
+    { "vpos",       "set initial vertical position",      OFFSET(v_ipos),  AV_OPT_TYPE_FLOAT, {.dbl=0.},   0, 1., FLAGS },
+    { NULL }
+};
+
+AVFILTER_DEFINE_CLASS(scroll);
+
+static const AVFilterPad scroll_inputs[] = {
+    {
+        .name           = "default",
+        .type           = AVMEDIA_TYPE_VIDEO,
+        .config_props   = config_input,
+        .filter_frame   = filter_frame,
+    },
+    { NULL }
+};
+
+static const AVFilterPad scroll_outputs[] = {
+    {
+        .name = "default",
+        .type = AVMEDIA_TYPE_VIDEO,
+    },
+    { NULL }
+};
+
+AVFilter ff_vf_scroll = {
+    .name          = "scroll",
+    .description   = NULL_IF_CONFIG_SMALL("Scroll input video."),
+    .priv_size     = sizeof(ScrollContext),
+    .priv_class    = &scroll_class,
+    .query_formats = query_formats,
+    .inputs        = scroll_inputs,
+    .outputs       = scroll_outputs,
+    .flags         = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC,
+};