[FFmpeg-devel] [PATCH 2/2] Add hflip filter.

Michael Niedermayer michaelni
Wed Aug 4 14:23:49 CEST 2010


On Sat, Jul 31, 2010 at 02:07:29AM +0200, Stefano Sabatini wrote:
> ---
>  doc/filters.texi         |   10 ++++
>  libavfilter/Makefile     |    1 +
>  libavfilter/allfilters.c |    1 +
>  libavfilter/vf_hflip.c   |  127 ++++++++++++++++++++++++++++++++++++++++++++++
>  4 files changed, 139 insertions(+), 0 deletions(-)
>  create mode 100644 libavfilter/vf_hflip.c
> 
> diff --git a/doc/filters.texi b/doc/filters.texi
> index 3ce60b3..4186301 100644
> --- a/doc/filters.texi
> +++ b/doc/filters.texi
> @@ -56,6 +56,16 @@ The following command:
>  
>  will convert the input video to the format ``yuv420p''.
>  
> + at section hflip
> +
> +Flip the input video horizontally.
> +
> +For example to horizontally flip the video in input with
> + at file{ffmpeg}:
> + at example
> +ffmpeg -i in.avi -vf "hflip" out.avi
> + at end example
> +
>  @section noformat
>  
>  Force libavfilter not to use any of the specified pixel formats for the
> diff --git a/libavfilter/Makefile b/libavfilter/Makefile
> index b7d3ddb..e25ff85 100644
> --- a/libavfilter/Makefile
> +++ b/libavfilter/Makefile
> @@ -17,6 +17,7 @@ OBJS = allfilters.o                                                     \
>  OBJS-$(CONFIG_ASPECT_FILTER)                 += vf_aspect.o
>  OBJS-$(CONFIG_CROP_FILTER)                   += vf_crop.o
>  OBJS-$(CONFIG_FORMAT_FILTER)                 += vf_format.o
> +OBJS-$(CONFIG_HFLIP_FILTER)                  += vf_hflip.o
>  OBJS-$(CONFIG_NOFORMAT_FILTER)               += vf_format.o
>  OBJS-$(CONFIG_NULL_FILTER)                   += vf_null.o
>  OBJS-$(CONFIG_PAD_FILTER)                    += vf_pad.o
> diff --git a/libavfilter/allfilters.c b/libavfilter/allfilters.c
> index 3282a31..657e5d5 100644
> --- a/libavfilter/allfilters.c
> +++ b/libavfilter/allfilters.c
> @@ -37,6 +37,7 @@ void avfilter_register_all(void)
>      REGISTER_FILTER (ASPECT,      aspect,      vf);
>      REGISTER_FILTER (CROP,        crop,        vf);
>      REGISTER_FILTER (FORMAT,      format,      vf);
> +    REGISTER_FILTER (HFLIP,       hflip,       vf);
>      REGISTER_FILTER (NOFORMAT,    noformat,    vf);
>      REGISTER_FILTER (NULL,        null,        vf);
>      REGISTER_FILTER (PAD,         pad,         vf);
> diff --git a/libavfilter/vf_hflip.c b/libavfilter/vf_hflip.c
> new file mode 100644
> index 0000000..199b33f
> --- /dev/null
> +++ b/libavfilter/vf_hflip.c
> @@ -0,0 +1,127 @@
> +/*
> + * Copyright (c) 2007 Benoit Fouet
> + * Copyright (c) 2010 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 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
> + */
> +
> +/**
> + * @flip
> + * horizontal flip filter
> + */
> +
> +#include "avfilter.h"
> +#include "libavutil/pixdesc.h"
> +
> +typedef struct {
> +    int max_step[4];    ///< max pixel step for each plane, expressed as a number of bytes
> +    int hsub, vsub;     ///< chroma subsampling
> +} FlipContext;
> +
> +static int query_formats(AVFilterContext *ctx)
> +{
> +    static const enum PixelFormat pix_fmts[] = {
> +        PIX_FMT_RGB48BE,      PIX_FMT_RGB48LE,
> +        PIX_FMT_ARGB,         PIX_FMT_RGBA,
> +        PIX_FMT_ABGR,         PIX_FMT_BGRA,
> +        PIX_FMT_RGB24,        PIX_FMT_BGR24,
> +        PIX_FMT_RGB565BE,     PIX_FMT_RGB565LE,
> +        PIX_FMT_RGB555BE,     PIX_FMT_RGB555LE,
> +        PIX_FMT_BGR565BE,     PIX_FMT_BGR565LE,
> +        PIX_FMT_BGR555BE,     PIX_FMT_BGR555LE,
> +        PIX_FMT_GRAY16BE,     PIX_FMT_GRAY16LE,
> +        PIX_FMT_YUV420P16LE,  PIX_FMT_YUV420P16BE,
> +        PIX_FMT_YUV422P16LE,  PIX_FMT_YUV422P16BE,
> +        PIX_FMT_YUV444P16LE,  PIX_FMT_YUV444P16BE,
> +        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_RGB8,         PIX_FMT_BGR8,
> +        PIX_FMT_RGB4_BYTE,    PIX_FMT_BGR4_BYTE,
> +        PIX_FMT_PAL8,         PIX_FMT_GRAY8,
> +        PIX_FMT_NONE
> +    };
> +
> +    avfilter_set_common_formats(ctx, avfilter_make_format_list(pix_fmts));
> +    return 0;
> +}
> +
> +static int config_props(AVFilterLink *inlink)
> +{
> +    FlipContext *flip = inlink->dst->priv;
> +    const AVPixFmtDescriptor *pix_desc = &av_pix_fmt_descriptors[inlink->format];
> +    int i;
> +
> +    memset(flip->max_step, 0, sizeof(flip->max_step));
> +    for (i = 0; i < 4; i++) {
> +        const AVComponentDescriptor *comp = &(pix_desc->comp[i]);
> +        if ((comp->step_minus1+1) > flip->max_step[comp->plane])
> +            flip->max_step[comp->plane] = comp->step_minus1+1;
> +    }
> +
> +    flip->hsub = av_pix_fmt_descriptors[inlink->format].log2_chroma_w;
> +    flip->vsub = av_pix_fmt_descriptors[inlink->format].log2_chroma_h;
> +
> +    return 0;
> +}
> +
> +static void draw_slice(AVFilterLink *inlink, int y, int h, int slice_dir)
> +{
> +    FlipContext *flip = inlink->dst->priv;
> +    AVFilterPicRef *inpic  = inlink->cur_pic;
> +    AVFilterPicRef *outpic = inlink->dst->outputs[0]->outpic;
> +    uint8_t *inrow, *outrow;
> +    int i, j, plane, step, hsub, vsub;
> +
> +    for (plane = 0; plane < 4 && inpic->data[plane]; plane++) {
> +        step = flip->max_step[plane];
> +        hsub = (plane == 1 || plane == 2) ? flip->hsub : 0;
> +        vsub = (plane == 1 || plane == 2) ? flip->vsub : 0;
> +
> +        outrow = outpic->data[plane] + (y>>vsub) * outpic->linesize[plane];
> +        inrow  = inpic ->data[plane] + (y>>vsub) * inpic ->linesize[plane] + ((inlink->w >> hsub) - 1) * step;
> +        for (i = 0; i < h>>vsub; i++) {
> +            for (j = 0; j < (inlink->w >> hsub); j++)
> +                memcpy(outrow + j*step, inrow - j*step, step);

variable length memcpy on a per pixel base is slow


[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Observe your enemies, for they first find out your faults. -- Antisthenes
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