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

 - drop support for avconv without libavfilter

 - add libavresample audio conversion library

 - audio filters support in libavfilter and avconv

+- add fps filter

 version 0.8:

@@ -814,6 +814,19 @@ format=yuv420p

 format=yuv420p:yuv444p:yuv410p

 @end example

+@section fps

+

+Convert the video to specified constant framerate by duplicating or dropping

+frames as necessary.

+

+This filter accepts the following named parameters:

+@table @option

+

+@item fps

+Desired output framerate.

+

+@end table

+

 @anchor{frei0r}

 @section frei0r

@@ -46,6 +46,7 @@ OBJS-$(CONFIG_FADE_FILTER)                   += vf_fade.o

 OBJS-$(CONFIG_FIELDORDER_FILTER)             += vf_fieldorder.o

 OBJS-$(CONFIG_FIFO_FILTER)                   += vf_fifo.o

 OBJS-$(CONFIG_FORMAT_FILTER)                 += vf_format.o

+OBJS-$(CONFIG_FPS_FILTER)                    += vf_fps.o

 OBJS-$(CONFIG_FREI0R_FILTER)                 += vf_frei0r.o

 OBJS-$(CONFIG_GRADFUN_FILTER)                += vf_gradfun.o

 OBJS-$(CONFIG_HFLIP_FILTER)                  += vf_hflip.o

@@ -55,6 +55,7 @@ void avfilter_register_all(void)

     REGISTER_FILTER (FIELDORDER,  fieldorder,  vf);

     REGISTER_FILTER (FIFO,        fifo,        vf);

     REGISTER_FILTER (FORMAT,      format,      vf);

+    REGISTER_FILTER (FPS,         fps,         vf);

     REGISTER_FILTER (FREI0R,      frei0r,      vf);

     REGISTER_FILTER (GRADFUN,     gradfun,     vf);

     REGISTER_FILTER (HFLIP,       hflip,       vf);

@@ -29,7 +29,7 @@

 #include "libavutil/avutil.h"

 #define LIBAVFILTER_VERSION_MAJOR  2

-#define LIBAVFILTER_VERSION_MINOR  17

+#define LIBAVFILTER_VERSION_MINOR  18

 #define LIBAVFILTER_VERSION_MICRO  0

 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \

new file mode 100644

@@ -0,0 +1,271 @@

+/*

+ * This file is part of Libav.

+ *

+ * Libav 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.

+ *

+ * Libav 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 Libav; if not, write to the Free Software

+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

+ */

+

+/**

+ * @file

+ * a filter enforcing given constant framerate

+ */

+

+#include "libavutil/fifo.h"

+#include "libavutil/mathematics.h"

+#include "libavutil/opt.h"

+#include "libavutil/parseutils.h"

+

+#include "avfilter.h"

+

+typedef struct FPSContext {

+    const AVClass *class;

+

+    AVFifoBuffer *fifo;     ///< store frames until we get two successive timestamps

+

+    /* timestamps in input timebase */

+    int64_t first_pts;      ///< pts of the first frame that arrived on this filter

+    int64_t pts;            ///< pts of the first frame currently in the fifo

+

+    AVRational framerate;   ///< target framerate

+    char *fps;              ///< a string describing target framerate

+

+    /* statistics */

+    int frames_in;             ///< number of frames on input

+    int frames_out;            ///< number of frames on output

+    int dup;                   ///< number of frames duplicated

+    int drop;                  ///< number of framed dropped

+} FPSContext;

+

+#define OFFSET(x) offsetof(FPSContext, x)

+#define V AV_OPT_FLAG_VIDEO_PARAM

+static const AVOption options[] = {

+    { "fps", "A string describing desired output framerate", OFFSET(fps), AV_OPT_TYPE_STRING, { .str = "25" }, .flags = V },

+    { NULL },

+};

+

+static const AVClass class = {

+    .class_name = "FPS filter",

+    .item_name  = av_default_item_name,

+    .option     = options,

+    .version    = LIBAVUTIL_VERSION_INT,

+};

+

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

+{

+    FPSContext *s = ctx->priv;

+    int ret;

+

+    s->class = &class;

+    av_opt_set_defaults(s);

+

+    if ((ret = av_set_options_string(s, args, "=", ":")) < 0) {

+        av_log(ctx, AV_LOG_ERROR, "Error parsing the options string %s.\n",

+               args);

+        return ret;

+    }

+

+    if ((ret = av_parse_video_rate(&s->framerate, s->fps)) < 0) {

+        av_log(ctx, AV_LOG_ERROR, "Error parsing framerate %s.\n", s->fps);

+        return ret;

+    }

+    av_opt_free(s);

+

+    if (!(s->fifo = av_fifo_alloc(2*sizeof(AVFilterBufferRef*))))

+        return AVERROR(ENOMEM);

+

+    av_log(ctx, AV_LOG_VERBOSE, "fps=%d/%d\n", s->framerate.num, s->framerate.den);

+    return 0;

+}

+

+static void flush_fifo(AVFifoBuffer *fifo)

+{

+    while (av_fifo_size(fifo)) {

+        AVFilterBufferRef *tmp;

+        av_fifo_generic_read(fifo, &tmp, sizeof(tmp), NULL);

+        avfilter_unref_buffer(tmp);

+    }

+}

+

+static av_cold void uninit(AVFilterContext *ctx)

+{

+    FPSContext *s = ctx->priv;

+    if (s->fifo) {

+        flush_fifo(s->fifo);

+        av_fifo_free(s->fifo);

+    }

+

+    av_log(ctx, AV_LOG_VERBOSE, "%d frames in, %d frames out; %d frames dropped, "

+           "%d frames duplicated.\n", s->frames_in, s->frames_out, s->drop, s->dup);

+}

+

+static int config_props(AVFilterLink* link)

+{

+    FPSContext   *s = link->src->priv;

+

+    link->time_base = (AVRational){ s->framerate.den, s->framerate.num };

+    link->w         = link->src->inputs[0]->w;

+    link->h         = link->src->inputs[0]->h;

+    s->pts          = AV_NOPTS_VALUE;

+

+    return 0;

+}

+

+static int request_frame(AVFilterLink *outlink)

+{

+    AVFilterContext *ctx = outlink->src;

+    FPSContext        *s = ctx->priv;

+    int frames_out = s->frames_out;

+    int ret = 0;

+

+    while (ret >= 0 && s->frames_out == frames_out)

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

+

+    /* flush the fifo */

+    if (ret == AVERROR_EOF && av_fifo_size(s->fifo)) {

+        int i;

+        for (i = 0; av_fifo_size(s->fifo); i++) {

+            AVFilterBufferRef *buf;

+

+            av_fifo_generic_read(s->fifo, &buf, sizeof(buf), NULL);

+            buf->pts = av_rescale_q(s->first_pts, ctx->inputs[0]->time_base,

+                                    outlink->time_base) + s->frames_out;

+

+            avfilter_start_frame(outlink, buf);

+            avfilter_draw_slice(outlink, 0, outlink->h, 1);

+            avfilter_end_frame(outlink);

+            s->frames_out++;

+        }

+        return 0;

+    }

+

+    return ret;

+}

+

+static int write_to_fifo(AVFifoBuffer *fifo, AVFilterBufferRef *buf)

+{

+    int ret;

+

+    if (!av_fifo_space(fifo) &&

+        (ret = av_fifo_realloc2(fifo, 2*av_fifo_size(fifo))))

+        return ret;

+

+    av_fifo_generic_write(fifo, &buf, sizeof(buf), NULL);

+    return 0;

+}

+

+static void end_frame(AVFilterLink *inlink)

+{

+    AVFilterContext    *ctx = inlink->dst;

+    FPSContext           *s = ctx->priv;

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

+    AVFilterBufferRef  *buf = inlink->cur_buf;

+    int64_t delta;

+    int i;

+

+    s->frames_in++;

+    /* discard frames until we get the first timestamp */

+    if (s->pts == AV_NOPTS_VALUE) {

+        if (buf->pts != AV_NOPTS_VALUE) {

+            write_to_fifo(s->fifo, buf);

+            s->first_pts = s->pts = buf->pts;

+        } else {

+            av_log(ctx, AV_LOG_WARNING, "Discarding initial frame(s) with no "

+                   "timestamp.\n");

+            avfilter_unref_buffer(buf);

+            s->drop++;

+        }

+        return;

+    }

+

+    /* now wait for the next timestamp */

+    if (buf->pts == AV_NOPTS_VALUE) {

+        write_to_fifo(s->fifo, buf);

+        return;

+    }

+

+    /* number of output frames */

+    delta = av_rescale_q(buf->pts - s->pts, inlink->time_base,

+                         outlink->time_base);

+

+    if (delta < 1) {

+        /* drop the frame and everything buffered except the first */

+        AVFilterBufferRef *tmp;

+        int drop = av_fifo_size(s->fifo)/sizeof(AVFilterBufferRef*);

+

+        av_log(ctx, AV_LOG_DEBUG, "Dropping %d frame(s).\n", drop);

+        s->drop += drop;

+

+        av_fifo_generic_read(s->fifo, &tmp, sizeof(tmp), NULL);

+        flush_fifo(s->fifo);

+        write_to_fifo(s->fifo, tmp);

+

+        avfilter_unref_buffer(buf);

+        return;

+    }

+

+    /* can output >= 1 frames */

+    for (i = 0; i < delta; i++) {

+        AVFilterBufferRef *buf_out;

+        av_fifo_generic_read(s->fifo, &buf_out, sizeof(buf_out), NULL);

+

+        /* duplicate the frame if needed */

+        if (!av_fifo_size(s->fifo) && i < delta - 1) {

+            av_log(ctx, AV_LOG_DEBUG, "Duplicating frame.\n");

+            write_to_fifo(s->fifo, avfilter_ref_buffer(buf_out, AV_PERM_READ));

+            s->dup++;

+        }

+

+        buf_out->pts = av_rescale_q(s->first_pts, inlink->time_base,

+                                    outlink->time_base) + s->frames_out;

+

+        avfilter_start_frame(outlink, buf_out);

+        avfilter_draw_slice(outlink, 0, outlink->h, 1);

+        avfilter_end_frame(outlink);

+        s->frames_out++;

+    }

+    flush_fifo(s->fifo);

+

+    write_to_fifo(s->fifo, buf);

+    s->pts = s->first_pts + av_rescale_q(s->frames_out, outlink->time_base, inlink->time_base);

+}

+

+static void null_start_frame(AVFilterLink *link, AVFilterBufferRef *buf)

+{

+}

+

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

+{

+}

+

+AVFilter avfilter_vf_fps = {

+    .name        = "fps",

+    .description = NULL_IF_CONFIG_SMALL("Force constant framerate"),

+

+    .init      = init,

+    .uninit    = uninit,

+

+    .priv_size = sizeof(FPSContext),

+

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

+                                    .type            = AVMEDIA_TYPE_VIDEO,

+                                    .start_frame     = null_start_frame,

+                                    .draw_slice      = null_draw_slice,

+                                    .end_frame       = end_frame, },

+                                  { .name = NULL}},

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

+                                    .type            = AVMEDIA_TYPE_VIDEO,

+                                    .request_frame   = request_frame,

+                                    .config_props    = config_props},

+                                  { .name = NULL}},

+};