@@ -58,6 +58,7 @@ version next:

   instead of AV_CODEC_ID_TEXT

 - smartblur filter ported from MPlayer

 - CPiA decoder

+- decimate filter ported from MPlayer

 version 0.11:

@@ -1889,6 +1889,7 @@ blackframe_filter_deps="gpl"

 boxblur_filter_deps="gpl"

 colormatrix_filter_deps="gpl"

 cropdetect_filter_deps="gpl"

+decimate_filter_deps="gpl"

 delogo_filter_deps="gpl"

 deshake_filter_deps="avcodec"

 drawtext_filter_deps="libfreetype"

@@ -1539,6 +1539,43 @@ indicates never reset and return the largest area encountered during

 playback.

 @end table

+@section decimate

+

+This filter drops frames that do not differ greatly from the previous

+frame in order to reduce framerate.  The main use of this filter is

+for very-low-bitrate encoding (e.g. streaming over dialup modem), but

+it could in theory be used for fixing movies that were

+inverse-telecined incorrectly.

+

+It accepts the following parameters:

+@var{max}:@var{hi}:@var{lo}:@var{frac}.

+

+@table @option

+

+@item max

+Set the maximum number of consecutive frames which can be dropped (if

+positive), or the minimum interval between dropped frames (if

+negative). If the value is 0, the frame is dropped unregarding the

+number of previous sequentially dropped frames.

+

+Default value is 0.

+

+@item hi, lo, frac

+Set the dropping threshold values.

+

+Values for @var{hi} and @var{lo} are for 8x8 pixel blocks and

+represent actual pixel value differences, so a threshold of 64

+corresponds to 1 unit of difference for each pixel, or the same spread

+out differently over the block.

+

+A frame is a candidate for dropping if no 8x8 blocks differ by more

+than a threshold of @var{hi}, and if no more than @var{frac} blocks (1

+meaning the whole image) differ by more than a threshold of @var{lo}.

+

+Default value for @var{hi} is 64*12, default value for @var{lo} is

+64*5, and default value for @var{frac} is 0.33.

+@end table

+

 @section delogo

 Suppress a TV station logo by a simple interpolation of the surrounding

@@ -10,6 +10,7 @@ FFLIBS-$(CONFIG_ACONVERT_FILTER)             += swresample

 FFLIBS-$(CONFIG_AMOVIE_FILTER)               += avformat avcodec

 FFLIBS-$(CONFIG_ARESAMPLE_FILTER)            += swresample

 FFLIBS-$(CONFIG_ATEMPO_FILTER)               += avcodec

+FFLIBS-$(CONFIG_DECIMATE_FILTER)             += avcodec

 FFLIBS-$(CONFIG_MOVIE_FILTER)                += avformat avcodec

 FFLIBS-$(CONFIG_PAN_FILTER)                  += swresample

 FFLIBS-$(CONFIG_REMOVELOGO_FILTER)           += avformat avcodec

@@ -88,6 +89,7 @@ OBJS-$(CONFIG_COLORMATRIX_FILTER)            += vf_colormatrix.o

 OBJS-$(CONFIG_COPY_FILTER)                   += vf_copy.o

 OBJS-$(CONFIG_CROP_FILTER)                   += vf_crop.o

 OBJS-$(CONFIG_CROPDETECT_FILTER)             += vf_cropdetect.o

+OBJS-$(CONFIG_DECIMATE_FILTER)               += vf_decimate.o

 OBJS-$(CONFIG_DELOGO_FILTER)                 += vf_delogo.o

 OBJS-$(CONFIG_DESHAKE_FILTER)                += vf_deshake.o

 OBJS-$(CONFIG_DRAWBOX_FILTER)                += vf_drawbox.o

@@ -78,6 +78,7 @@ void avfilter_register_all(void)

     REGISTER_FILTER (COPY,        copy,        vf);

     REGISTER_FILTER (CROP,        crop,        vf);

     REGISTER_FILTER (CROPDETECT,  cropdetect,  vf);

+    REGISTER_FILTER (DECIMATE,    decimate,    vf);

     REGISTER_FILTER (DELOGO,      delogo,      vf);

     REGISTER_FILTER (DESHAKE,     deshake,     vf);

     REGISTER_FILTER (DRAWBOX,     drawbox,     vf);

@@ -29,8 +29,8 @@

 #include "libavutil/avutil.h"

 #define LIBAVFILTER_VERSION_MAJOR  3

-#define LIBAVFILTER_VERSION_MINOR  14

-#define LIBAVFILTER_VERSION_MICRO 101

+#define LIBAVFILTER_VERSION_MINOR  15

+#define LIBAVFILTER_VERSION_MICRO 100

 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \

                                                LIBAVFILTER_VERSION_MINOR, \

new file mode 100644

@@ -0,0 +1,268 @@

+/*

+ * Copyright (c) 2003 Rich Felker

+ * Copyright (c) 2012 Stefano Sabatini

+ *

+ * This file is part of FFmpeg.

+ *

+ * FFmpeg is free software; you can redistribute it and/or modify

+ * it under the terms of the GNU General Public License as published by

+ * the Free Software Foundation; either version 2 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 General Public License for more details.

+ *

+ * You should have received a copy of the GNU 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 decimate filter, ported from libmpcodecs/vf_decimate.c by

+ * Rich Felker.

+ */

+

+#include "libavutil/pixdesc.h"

+#include "libavutil/timestamp.h"

+#include "libavcodec/dsputil.h"

+#include "avfilter.h"

+#include "internal.h"

+#include "formats.h"

+#include "video.h"

+

+typedef struct {

+    int lo, hi;                    ///< lower and higher threshold number of differences

+                                   ///< values for 8x8 blocks

+

+    float frac;                    ///< threshold of changed pixels over the total fraction

+

+    int max_drop_count;            ///< if positive: maximum number of sequential frames to drop

+                                   ///< if negative: minimum number of frames between two drops

+

+    int drop_count;                ///< if positive: number of frames sequentially dropped

+                                   ///< if negative: number of sequential frames which were not dropped

+

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

+    AVFilterBufferRef *ref;        ///< reference picture

+    DSPContext dspctx;             ///< context providing optimized diff routines

+    AVCodecContext *avctx;         ///< codec context required for the DSPContext

+} DecimateContext;

+

+/**

+ * Return 1 if the two planes are different, 0 otherwise.

+ */

+static int diff_planes(AVFilterContext *ctx,

+                       uint8_t *cur, uint8_t *ref, int linesize,

+                       int w, int h)

+{

+    DecimateContext *decimate = ctx->priv;

+    DSPContext *dspctx = &decimate->dspctx;

+

+    int x, y;

+    int d, c = 0;

+    int t = (w/16)*(h/16)*decimate->frac;

+    DCTELEM block[8*8];

+

+    /* compute difference for blocks of 8x8 bytes */

+    for (y = 0; y < h-7; y += 4) {

+        for (x = 8; x < w-7; x += 4) {

+            dspctx->diff_pixels(block,

+                                cur+x+y*linesize,

+                                ref+x+y*linesize, linesize);

+            d = dspctx->sum_abs_dctelem(block);

+            if (d > decimate->hi)

+                return 1;

+            if (d > decimate->lo) {

+                c++;

+                if (c > t)

+                    return 1;

+            }

+        }

+    }

+    return 0;

+}

+

+/**

+ * Tell if the frame should be decimated, for example if it is no much

+ * different with respect to the reference frame ref.

+ */

+static int decimate_frame(AVFilterContext *ctx,

+                          AVFilterBufferRef *cur, AVFilterBufferRef *ref)

+{

+    DecimateContext *decimate = ctx->priv;

+    int plane;

+

+    if (decimate->max_drop_count > 0 &&

+        decimate->drop_count >= decimate->max_drop_count)

+        return 0;

+    if (decimate->max_drop_count < 0 &&

+        (decimate->drop_count-1) > decimate->max_drop_count)

+        return 0;

+

+    for (plane = 0; ref->data[plane] && ref->linesize[plane]; plane++) {

+        int vsub = plane == 1 || plane == 2 ? decimate->vsub : 0;

+        int hsub = plane == 1 || plane == 2 ? decimate->hsub : 0;

+        if (diff_planes(ctx,

+                        cur->data[plane], ref->data[plane], ref->linesize[plane],

+                        ref->video->w>>hsub, ref->video->h>>vsub))

+            return 0;

+    }

+

+    return 1;

+}

+

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

+{

+    DecimateContext *decimate = ctx->priv;

+

+    /* set default values */

+    decimate->drop_count = decimate->max_drop_count = 0;

+    decimate->lo = 64*5;

+    decimate->hi = 64*12;

+    decimate->frac = 0.33;

+

+    if (args) {

+        char c1, c2, c3, c4;

+        int n = sscanf(args, "%d%c%d%c%d%c%f%c",

+                       &decimate->max_drop_count, &c1,

+                       &decimate->hi, &c2, &decimate->lo, &c3,

+                       &decimate->frac, &c4);

+        if (n != 1 &&

+            (n != 3 || c1 != ':') &&

+            (n != 5 || c1 != ':' || c2 != ':') &&

+            (n != 7 || c1 != ':' || c2 != ':' || c3 != ':')) {

+            av_log(ctx, AV_LOG_ERROR,

+                   "Invalid syntax for argument '%s': "

+                   "must be in the form 'max:hi:lo:frac'\n", args);

+            return AVERROR(EINVAL);

+        }

+    }

+

+    av_log(ctx, AV_LOG_VERBOSE, "max_drop_count:%d hi:%d lo:%d frac:%f\n",

+           decimate->max_drop_count, decimate->hi, decimate->lo, decimate->frac);

+

+    decimate->avctx = avcodec_alloc_context3(NULL);

+    if (!decimate->avctx)

+        return AVERROR(ENOMEM);

+    dsputil_init(&decimate->dspctx, decimate->avctx);

+

+    return 0;

+}

+

+static av_cold void uninit(AVFilterContext *ctx)

+{

+    DecimateContext *decimate = ctx->priv;

+    avfilter_unref_bufferp(&decimate->ref);

+    avcodec_close(decimate->avctx);

+    av_freep(&decimate->avctx);

+}

+

+static int query_formats(AVFilterContext *ctx)

+{

+    static const enum PixelFormat pix_fmts[] = {

+        PIX_FMT_YUV444P,      PIX_FMT_YUV422P,

+        PIX_FMT_YUV420P,      PIX_FMT_YUV411P,

+        PIX_FMT_YUV410P,      PIX_FMT_YUV440P,

+        PIX_FMT_YUVJ444P,     PIX_FMT_YUVJ422P,

+        PIX_FMT_YUVJ420P,     PIX_FMT_YUVJ440P,

+        PIX_FMT_YUVA420P,

+        PIX_FMT_NONE

+    };

+

+    ff_set_common_formats(ctx, ff_make_format_list(pix_fmts));

+

+    return 0;

+}

+

+static int config_input(AVFilterLink *inlink)

+{

+    AVFilterContext *ctx = inlink->dst;

+    DecimateContext *decimate = ctx->priv;

+    const AVPixFmtDescriptor *pix_desc = &av_pix_fmt_descriptors[inlink->format];

+    decimate->hsub = pix_desc->log2_chroma_w;

+    decimate->vsub = pix_desc->log2_chroma_h;

+

+    return 0;

+}

+

+static int start_frame(AVFilterLink *inlink, AVFilterBufferRef *picref) { return 0; }

+

+static int draw_slice(AVFilterLink *inlink, int y, int h, int slice_dir) { return 0; }

+

+static int end_frame(AVFilterLink *inlink)

+{

+    DecimateContext *decimate = inlink->dst->priv;

+    AVFilterBufferRef *cur = inlink->cur_buf;

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

+    int ret;

+

+    if (decimate->ref && decimate_frame(inlink->dst, cur, decimate->ref)) {

+        decimate->drop_count = FFMAX(1, decimate->drop_count+1);

+    } else {

+        avfilter_unref_buffer(decimate->ref);

+        decimate->ref = cur;

+        inlink->cur_buf = NULL;

+        decimate->drop_count = FFMIN(-1, decimate->drop_count-1);

+

+        if ((ret = ff_start_frame(outlink,

+                                  avfilter_ref_buffer(cur, ~AV_PERM_WRITE)) < 0) ||

+            (ret = ff_draw_slice(outlink, 0, inlink->h, 1)) < 0 ||

+            (ret = ff_end_frame(outlink)) < 0)

+            return ret;

+    }

+

+    av_log(inlink->dst, AV_LOG_DEBUG,

+           "%s pts:%s pts_time:%s drop_count:%d\n",

+           decimate->drop_count > 0 ? "drop" : "keep",

+           av_ts2str(cur->pts), av_ts2timestr(cur->pts, &inlink->time_base),

+           decimate->drop_count);

+

+    return 0;

+}

+

+static int request_frame(AVFilterLink *outlink)

+{

+    DecimateContext *decimate = outlink->src->priv;

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

+    int ret;

+

+    do {

+        ret = ff_request_frame(inlink);

+    } while (decimate->drop_count > 0 && ret >= 0);

+

+    return ret;

+}

+

+AVFilter avfilter_vf_decimate = {

+    .name        = "decimate",

+    .description = NULL_IF_CONFIG_SMALL("Remove near-duplicate frames."),

+    .init        = init,

+    .uninit      = uninit,

+

+    .priv_size = sizeof(DecimateContext),

+    .query_formats = query_formats,

+

+    .inputs = (const AVFilterPad[]) {

+        {

+            .name             = "default",

+            .type             = AVMEDIA_TYPE_VIDEO,

+            .get_video_buffer = ff_null_get_video_buffer,

+            .config_props     = config_input,

+            .start_frame      = start_frame,

+            .draw_slice       = draw_slice,

+            .end_frame        = end_frame,

+            .min_perms        = AV_PERM_READ | AV_PERM_PRESERVE,

+        },

+        { .name = NULL }

+    },

+    .outputs = (const AVFilterPad[]) {

+        {

+            .name          = "default",

+            .type          = AVMEDIA_TYPE_VIDEO,

+            .request_frame = request_frame,

+        },

+        { .name = NULL }

+    },

+};