@@ -164,6 +164,31 @@ not specified it will use the default value of 16.

 Adding this in the beginning of filter chains should make filtering

 faster due to better use of the memory cache.

+@section scale

+

+Scale the input video to width:height and/or convert the image format.

+

+For example the command:

+

+@example

+./ffmpeg -i in.avi -vfilters "scale=200:100" out.avi

+@end example

+

+will scale the input video to a size of 200x100.

+

+If the input image format is different from the format requested by

+the next filter, the scale filter will convert the input to the

+requested format.

+

+If the value for ``width'' or ``height'' is 0, the respective input

+size is used for the output.

+

+If the value for ``width'' or ``height'' is -1, the scale filter will

+use, for the respective output size, a value that maintains the aspect

+ratio of the input image.

+

+The default value of ``width'' and ``height'' is 0.

+

 @section vflip

 Flip the input video vertically.

@@ -16,6 +16,7 @@ OBJS-$(CONFIG_CROP_FILTER)                   += vf_crop.o

 OBJS-$(CONFIG_FORMAT_FILTER)                 += vf_format.o

 OBJS-$(CONFIG_NOFORMAT_FILTER)               += vf_format.o

 OBJS-$(CONFIG_NULL_FILTER)                   += vf_null.o

+OBJS-$(CONFIG_SCALE_FILTER)                  += vf_scale.o

 OBJS-$(CONFIG_SLICIFY_FILTER)                += vf_slicify.o

 OBJS-$(CONFIG_VFLIP_FILTER)                  += vf_vflip.o

@@ -38,6 +38,7 @@ void avfilter_register_all(void)

     REGISTER_FILTER (FORMAT, format, vf);

     REGISTER_FILTER (NOFORMAT, noformat, vf);

     REGISTER_FILTER (NULL, null, vf);

+    REGISTER_FILTER (SCALE, scale, vf);

     REGISTER_FILTER (SLICIFY, slicify, vf);

     REGISTER_FILTER (VFLIP, vflip, vf);

 }

@@ -23,7 +23,7 @@

 #define AVFILTER_AVFILTER_H

 #define LIBAVFILTER_VERSION_MAJOR  1

-#define LIBAVFILTER_VERSION_MINOR  7

+#define LIBAVFILTER_VERSION_MINOR  8

 #define LIBAVFILTER_VERSION_MICRO  0

 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \

new file mode 100644

@@ -0,0 +1,203 @@

+/*

+ * copyright (c) 2007 Bobby Bingham

+ *

+ * 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

+ */

+

+/**

+ * @file libavfilter/vf_scale.c

+ * scale video filter

+ */

+

+#include "avfilter.h"

+#include "libswscale/swscale.h"

+

+typedef struct {

+    struct SwsContext *sws;     ///< software scaler context

+

+    /**

+     * New dimensions. Special values are:

+     *   0 = original width/height

+     *  -1 = keep original aspect

+     */

+    int w, h;

+

+    int hsub, vsub;             ///< chroma subsampling

+    int slice_y;                ///< top of current output slice

+    int slice_dir;              ///< detected slice direction order for the current frame

+    int input_is_pal;           ///< set to 1 if the input format is paletted

+} ScaleContext;

+

+static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)

+{

+    ScaleContext *scale = ctx->priv;

+

+    if (args)

+        sscanf(args, "%d:%d", &scale->w, &scale->h);

+

+    /* sanity check params */

+    if (scale->w <  -1 || scale->h <  -1) {

+        av_log(ctx, AV_LOG_ERROR, "Size values less than -1 are not acceptable.\n");

+        return -1;

+    }

+    if (scale->w == -1 && scale->h == -1)

+        scale->w = scale->h = 0;

+

+    return 0;

+}

+

+static av_cold void uninit(AVFilterContext *ctx)

+{

+    ScaleContext *scale = ctx->priv;

+    sws_freeContext(scale->sws);

+    scale->sws = NULL;

+}

+

+static int query_formats(AVFilterContext *ctx)

+{

+    AVFilterFormats *formats;

+

+    if (ctx->inputs[0]) {

+        formats = avfilter_all_colorspaces();

+        avfilter_formats_ref(formats, &ctx->inputs[0]->out_formats);

+    }

+    if (ctx->outputs[0]) {

+        formats = avfilter_all_colorspaces();

+        avfilter_formats_ref(formats, &ctx->outputs[0]->in_formats);

+    }

+

+    return 0;

+}

+

+static int config_props(AVFilterLink *outlink)

+{

+    AVFilterContext *ctx = outlink->src;

+    AVFilterLink *inlink = outlink->src->inputs[0];

+    ScaleContext *scale = ctx->priv;

+    int64_t w, h;

+

+    if (!(w = scale->w))

+        w = inlink->w;

+    if (!(h = scale->h))

+        h = inlink->h;

+    if (w == -1)

+        w = av_rescale(h, inlink->w, inlink->h);

+    if (h == -1)

+        h = av_rescale(w, inlink->h, inlink->w);

+

+    if (w > INT_MAX || h > INT_MAX ||

+        (h * inlink->w) > INT_MAX  ||

+        (w * inlink->h) > INT_MAX)

+        av_log(ctx, AV_LOG_ERROR, "Rescaled value for width or height is too big.\n");

+

+    outlink->w = w;

+    outlink->h = h;

+

+    /* TODO: make algorithm configurable */

+    scale->sws = sws_getContext(inlink ->w, inlink ->h, inlink ->format,

+                                outlink->w, outlink->h, outlink->format,

+                                SWS_BILINEAR, NULL, NULL, NULL);

+

+    av_log(ctx, AV_LOG_INFO, "w:%d h:%d fmt:%s\n",

+           outlink->w, outlink->h, avcodec_get_pix_fmt_name(outlink->format));

+

+    avcodec_get_chroma_sub_sample(outlink->format, &scale->hsub, &scale->vsub);

+

+    scale->input_is_pal = inlink->format == PIX_FMT_PAL8      ||

+                          inlink->format == PIX_FMT_BGR4_BYTE ||

+                          inlink->format == PIX_FMT_RGB4_BYTE ||

+                          inlink->format == PIX_FMT_BGR8      ||

+                          inlink->format == PIX_FMT_RGB8;

+

+    return !scale->sws;

+}

+

+static void start_frame(AVFilterLink *link, AVFilterPicRef *picref)

+{

+    ScaleContext *scale = link->dst->priv;

+    AVFilterLink *outlink = link->dst->outputs[0];

+    AVFilterPicRef *outpicref;

+

+    outpicref = avfilter_get_video_buffer(outlink, AV_PERM_WRITE, outlink->w, outlink->h);

+    outpicref->pts = picref->pts;

+    outlink->outpic = outpicref;

+

+    av_reduce(&outpicref->pixel_aspect.num, &outpicref->pixel_aspect.den,

+              (int64_t)picref->pixel_aspect.num * outlink->h * link->w,

+              (int64_t)picref->pixel_aspect.den * outlink->w * link->h,

+              INT_MAX);

+

+    scale->slice_dir = 0;

+    avfilter_start_frame(outlink, avfilter_ref_pic(outpicref, ~0));

+}

+

+static void draw_slice(AVFilterLink *link, int y, int h)

+{

+    ScaleContext *scale = link->dst->priv;

+    int out_h;

+    AVFilterPicRef *cur_pic = link->cur_pic;

+    uint8_t *data[4];

+

+    if (!scale->slice_dir) {

+        if (y != 0 && y + h != link->h) {

+            av_log(scale, AV_LOG_ERROR, "Slices start in the middle!\n");

+            return;

+        }

+        scale->slice_dir = y ?                       -1 : 1;

+        scale->slice_y   = y ? link->dst->outputs[0]->h : y;

+    }

+

+    data[0] = cur_pic->data[0] +  y               * cur_pic->linesize[0];

+    data[1] = scale->input_is_pal ?

+              cur_pic->data[1] :

+              cur_pic->data[1] + (y>>scale->vsub) * cur_pic->linesize[1];

+    data[2] = cur_pic->data[2] + (y>>scale->vsub) * cur_pic->linesize[2];

+    data[3] = cur_pic->data[3] +  y               * cur_pic->linesize[3];

+

+    out_h = sws_scale(scale->sws, data, cur_pic->linesize, y, h,

+                      link->dst->outputs[0]->outpic->data,

+                      link->dst->outputs[0]->outpic->linesize);

+

+    if (scale->slice_dir == -1)

+        scale->slice_y -= out_h;

+    avfilter_draw_slice(link->dst->outputs[0], scale->slice_y, out_h);

+    if (scale->slice_dir == 1)

+        scale->slice_y += out_h;

+}

+

+AVFilter avfilter_vf_scale = {

+    .name      = "scale",

+    .description = "Scale the input video to width:height size and/or convert the image format.",

+

+    .init      = init,

+    .uninit    = uninit,

+

+    .query_formats = query_formats,

+

+    .priv_size = sizeof(ScaleContext),

+

+    .inputs    = (AVFilterPad[]) {{ .name             = "default",

+                                    .type             = CODEC_TYPE_VIDEO,

+                                    .start_frame      = start_frame,

+                                    .draw_slice       = draw_slice,

+                                    .min_perms        = AV_PERM_READ, },

+                                  { .name = NULL}},

+    .outputs   = (AVFilterPad[]) {{ .name             = "default",

+                                    .type             = CODEC_TYPE_VIDEO,

+                                    .config_props     = config_props, },

+                                  { .name = NULL}},

+};