[FFmpeg-devel] [PATCH] avfilter: Add reverse filter

Clément Bœsch u at pkh.me
Thu Jul 16 20:43:12 CEST 2015


On Thu, Jul 16, 2015 at 05:43:59PM +0000, Derek Buitenhuis wrote:
> Signed-off-by: Derek Buitenhuis <derek.buitenhuis at gmail.com>
> ---
> The design is how ubitux requested. Use trim with it or risk using ALL THEM MEMORY.

;)

> ---
>  doc/filters.texi         |   4 ++
>  libavfilter/Makefile     |   1 +
>  libavfilter/allfilters.c |   1 +
>  libavfilter/version.h    |   2 +-
>  libavfilter/vf_reverse.c | 145 +++++++++++++++++++++++++++++++++++++++++++++++
>  5 files changed, 152 insertions(+), 1 deletion(-)
>  create mode 100644 libavfilter/vf_reverse.c
> 
> diff --git a/doc/filters.texi b/doc/filters.texi
> index 3b4ec2c..7b0410a 100644
> --- a/doc/filters.texi
> +++ b/doc/filters.texi
> @@ -8247,6 +8247,10 @@ 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.
>  
> + at section reverse
> +
> +Reverses a clip. Requires memory to buffer the entire clip, so trimming is suggested.

We use infinitive form, so "Reverse".

You might want to print "Warning: this filter requires ..."

Can you add an example to make sure users don't membomb too much their
OS?

> +
>  @section rotate
>  
>  Rotate video by an arbitrary angle expressed in radians.
> diff --git a/libavfilter/Makefile b/libavfilter/Makefile
> index 058b9e9..1638ae8 100644
> --- a/libavfilter/Makefile
> +++ b/libavfilter/Makefile
> @@ -185,6 +185,7 @@ 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
> diff --git a/libavfilter/allfilters.c b/libavfilter/allfilters.c
> index b0d8410..5e2a322 100644
> --- a/libavfilter/allfilters.c
> +++ b/libavfilter/allfilters.c
> @@ -200,6 +200,7 @@ 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);
> diff --git a/libavfilter/version.h b/libavfilter/version.h
> index 618c626..d22b2c5 100644
> --- a/libavfilter/version.h
> +++ b/libavfilter/version.h
> @@ -30,7 +30,7 @@
>  #include "libavutil/version.h"
>  
>  #define LIBAVFILTER_VERSION_MAJOR  5
> -#define LIBAVFILTER_VERSION_MINOR  22
> +#define LIBAVFILTER_VERSION_MINOR  23
>  #define LIBAVFILTER_VERSION_MICRO 100
>  
>  #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \
> diff --git a/libavfilter/vf_reverse.c b/libavfilter/vf_reverse.c
> new file mode 100644
> index 0000000..00512be
> --- /dev/null
> +++ b/libavfilter/vf_reverse.c
> @@ -0,0 +1,145 @@
> +/*
> + * 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 {
> +    const AVClass *class;
> +
> +    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 && !ctx->is_disabled && s->nb_frames > 0) {

is_disabled suggest a timeline support. You could add that if you feel
like it. That way, "reverse=enable='between(t,30,40)'" would reverse only
between t=30 and t=40 and pass through the rest of the time.

> +        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,
> +};
> -- 
> 1.8.3.1
> 

-- 
Clément B.
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 473 bytes
Desc: not available
URL: <http://ffmpeg.org/pipermail/ffmpeg-devel/attachments/20150716/e7b89099/attachment.sig>


More information about the ffmpeg-devel mailing list