@@ -18,6 +18,7 @@ version <next>:

 - libkvazaar HEVC encoder

 - erosion, dilation, deflate and inflate video filters

 - Dynamic Audio Normalizer as dynaudnorm filter

+- Reverse filter

 version 2.7:

@@ -8418,6 +8418,22 @@ pixels will slow things down on a large logo.

 This filter uses the repeat_field flag from the Video ES headers and hard repeats

 fields based on its value.

+@section reverse

+

+Reverse a clip.

+

+Warning: This iflter qequires memory to buffer the entire clip, so trimming is suggested.

+

+@subsection Examples

+

+@itemize

+@item

+Take the first 5 seconds of a clip, and reverse it.

+@example

+trim=end=5,reverse

+@end example

+@end itemize

+

 @section rotate

 Rotate video by an arbitrary angle expressed in radians.

@@ -186,6 +186,7 @@ OBJS-$(CONFIG_QP_FILTER)                     += vf_qp.o

 OBJS-$(CONFIG_REMOVEGRAIN_FILTER)            += vf_removegrain.o

 OBJS-$(CONFIG_REMOVELOGO_FILTER)             += bbox.o lswsutils.o lavfutils.o vf_removelogo.o

 OBJS-$(CONFIG_REPEATFIELDS_FILTER)           += vf_repeatfields.o

+OBJS-$(CONFIG_REVERSE_FILTER)                += vf_reverse.o

 OBJS-$(CONFIG_ROTATE_FILTER)                 += vf_rotate.o

 OBJS-$(CONFIG_SEPARATEFIELDS_FILTER)         += vf_separatefields.o

 OBJS-$(CONFIG_SAB_FILTER)                    += vf_sab.o

@@ -201,6 +201,7 @@ void avfilter_register_all(void)

     REGISTER_FILTER(REMOVEGRAIN,    removegrain,    vf);

     REGISTER_FILTER(REMOVELOGO,     removelogo,     vf);

     REGISTER_FILTER(REPEATFIELDS,   repeatfields,   vf);

+    REGISTER_FILTER(REVERSE,        reverse,        vf);

     REGISTER_FILTER(ROTATE,         rotate,         vf);

     REGISTER_FILTER(SAB,            sab,            vf);

     REGISTER_FILTER(SCALE,          scale,          vf);

@@ -30,7 +30,7 @@

 #include "libavutil/version.h"

 #define LIBAVFILTER_VERSION_MAJOR  5

-#define LIBAVFILTER_VERSION_MINOR  23

+#define LIBAVFILTER_VERSION_MINOR  24

 #define LIBAVFILTER_VERSION_MICRO 100

 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \

new file mode 100644

@@ -0,0 +1,142 @@

+/*

+ * Copyright (c) 2015 Derek Buitenhuis

+ *

+ * 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/opt.h"

+#include "avfilter.h"

+#include "formats.h"

+#include "internal.h"

+#include "video.h"

+

+#define DEFAULT_LENGTH 300

+

+typedef struct ReverseContext {

+    int nb_frames;

+    AVFrame **frames;

+    unsigned int frames_size;

+    unsigned int pts_size;

+    int64_t *pts;

+    int flush_idx;

+} ReverseContext;

+

+static av_cold int init(AVFilterContext *ctx)

+{

+    ReverseContext *s = ctx->priv;

+

+    s->pts = av_fast_realloc(NULL, &s->pts_size,

+                             DEFAULT_LENGTH * sizeof(*(s->pts)));

+    if (!s->pts)

+        return AVERROR(ENOMEM);

+

+    s->frames = av_fast_realloc(NULL, &s->frames_size,

+                                DEFAULT_LENGTH * sizeof(*(s->frames)));

+    if (!s->frames) {

+        av_freep(&s->pts);

+        return AVERROR(ENOMEM);

+    }

+

+    return 0;

+}

+

+static av_cold void uninit(AVFilterContext *ctx)

+{

+    ReverseContext *s = ctx->priv;

+

+    av_freep(&s->pts);

+    av_freep(&s->frames);

+}

+

+static int config_output(AVFilterLink *outlink)

+{

+    outlink->flags |= FF_LINK_FLAG_REQUEST_LOOP;

+    return 0;

+}

+

+static int filter_frame(AVFilterLink *inlink, AVFrame *in)

+{

+    AVFilterContext *ctx = inlink->dst;

+    ReverseContext *s    = ctx->priv;

+

+    if (s->nb_frames + 1 > s->frames_size / sizeof(*(s->frames))) {

+        void *ptr;

+

+        ptr = av_fast_realloc(s->pts, &s->pts_size, s->pts_size * 2);

+        if (!ptr)

+            return AVERROR(ENOMEM);

+        s->pts = ptr;

+

+        ptr = av_fast_realloc(s->frames, &s->frames_size, s->frames_size * 2);

+        if (!ptr)

+            return AVERROR(ENOMEM);

+        s->frames = ptr;

+    }

+

+    s->frames[s->nb_frames] = in;

+    s->pts[s->nb_frames]    = in->pts;

+    s->nb_frames++;

+

+    return 0;

+}

+

+static int request_frame(AVFilterLink *outlink)

+{

+    AVFilterContext *ctx = outlink->src;

+    ReverseContext *s = ctx->priv;

+    int ret;

+

+    ret = ff_request_frame(ctx->inputs[0]);

+

+    if (ret == AVERROR_EOF && s->nb_frames > 0) {

+        AVFrame *out = s->frames[s->nb_frames - 1];

+        out->pts     = s->pts[s->flush_idx++];

+        ret          = ff_filter_frame(outlink, out);

+        s->nb_frames--;

+    }

+

+    return ret;

+}

+

+static const AVFilterPad reverse_inputs[] = {

+    {

+        .name         = "default",

+        .type         = AVMEDIA_TYPE_VIDEO,

+        .filter_frame = filter_frame,

+    },

+    { NULL }

+};

+

+static const AVFilterPad reverse_outputs[] = {

+    {

+        .name          = "default",

+        .type          = AVMEDIA_TYPE_VIDEO,

+        .request_frame = request_frame,

+        .config_props  = config_output,

+    },

+    { NULL }

+};

+

+AVFilter ff_vf_reverse = {

+    .name        = "reverse",

+    .description = NULL_IF_CONFIG_SMALL("Reverse a clip."),

+    .priv_size   = sizeof(ReverseContext),

+    .init        = init,

+    .uninit      = uninit,

+    .inputs      = reverse_inputs,

+    .outputs     = reverse_outputs,

+};