[FFmpeg-devel] [PATCH 5/5] lavfi: add tile video filter.

[Stefano Sabatini]

On date Thursday 2012-03-08 14:49:18 +0100, Nicolas George encoded:
> 
> Signed-off-by: Nicolas George <nicolas.george at normalesup.org>
> ---
>  Changelog                |    1 +
>  doc/filters.texi         |   11 +++
>  libavfilter/Makefile     |    1 +
>  libavfilter/allfilters.c |    1 +
>  libavfilter/vf_tile.c    |  206 ++++++++++++++++++++++++++++++++++++++++++++++
>  5 files changed, 220 insertions(+), 0 deletions(-)
>  create mode 100644 libavfilter/vf_tile.c
> 
> diff --git a/Changelog b/Changelog
> index 77112f6..666755b 100644
> --- a/Changelog
> +++ b/Changelog
> @@ -13,6 +13,7 @@ version next:
>  - bluray protocol
>  - blackdetect filter
>  - libutvideo encoder wrapper (--enable-libutvideo)
> +- tile video filter
>  
>  
>  version 0.10:
> diff --git a/doc/filters.texi b/doc/filters.texi
> index 2c646cb..2536029 100644
> --- a/doc/filters.texi
> +++ b/doc/filters.texi
> @@ -2651,6 +2651,17 @@ Complete example of a thumbnail creation with @command{ffmpeg}:
>  ffmpeg -i in.avi -vf thumbnail,scale=300:200 -frames:v 1 out.png
>  @end example
>  
> + at section tile
> +
> +Tile several successive frames together.
> +
> +It accepts as argument the tile size (i.e. the number of lines and columns)
> +in the form "@var{w}:@var{h}".

Nit: maybe WxH, so in case we need to add more parameters we won't
have conflicts (e.g. if we add a color option)

> +
> + at example
> +ffmpeg -skip_frame nokey -i file.avi -vf 'scale=128:72,tile=8:8' -an -vsync 0 keyframes%03d.png
> + at end example

Maybe some comments about why skip_frame is required.

> +
>  @section tinterlace
>  
>  Perform various types of temporal field interlacing.
> diff --git a/libavfilter/Makefile b/libavfilter/Makefile
> index df3a27f..c7fe271 100644
> --- a/libavfilter/Makefile
> +++ b/libavfilter/Makefile
> @@ -88,6 +88,7 @@ OBJS-$(CONFIG_SHOWINFO_FILTER)               += vf_showinfo.o
>  OBJS-$(CONFIG_SLICIFY_FILTER)                += vf_slicify.o
>  OBJS-$(CONFIG_SPLIT_FILTER)                  += vf_split.o
>  OBJS-$(CONFIG_THUMBNAIL_FILTER)              += vf_thumbnail.o
> +OBJS-$(CONFIG_TILE_FILTER)                   += vf_tile.o
>  OBJS-$(CONFIG_TINTERLACE_FILTER)             += vf_tinterlace.o
>  OBJS-$(CONFIG_TRANSPOSE_FILTER)              += vf_transpose.o
>  OBJS-$(CONFIG_UNSHARP_FILTER)                += vf_unsharp.o
> diff --git a/libavfilter/allfilters.c b/libavfilter/allfilters.c
> index f6230be..acac73a 100644
> --- a/libavfilter/allfilters.c
> +++ b/libavfilter/allfilters.c
> @@ -96,6 +96,7 @@ void avfilter_register_all(void)
>      REGISTER_FILTER (SLICIFY,     slicify,     vf);
>      REGISTER_FILTER (SPLIT,       split,       vf);
>      REGISTER_FILTER (THUMBNAIL,   thumbnail,   vf);
> +    REGISTER_FILTER (TILE,        tile,        vf);
>      REGISTER_FILTER (TINTERLACE,  tinterlace,  vf);
>      REGISTER_FILTER (TRANSPOSE,   transpose,   vf);
>      REGISTER_FILTER (UNSHARP,     unsharp,     vf);
> diff --git a/libavfilter/vf_tile.c b/libavfilter/vf_tile.c
> new file mode 100644
> index 0000000..3e71970
> --- /dev/null
> +++ b/libavfilter/vf_tile.c
> @@ -0,0 +1,206 @@
> +/*
> + * Copyright (c) 2012 Nicolas George
> + *
> + * 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
> + */
> +
> +/**
> + * @file
> + * tile video filter
> + */
> +
> +#include "libavutil/pixdesc.h"
> +#include "avfilter.h"
> +#include "drawutils.h"
> +
> +typedef struct {
> +    unsigned w, h;
> +    unsigned current;
> +    FFDrawContext draw;
> +    FFDrawColor blank;

> +} Tile_context;

Nit: TileContext for overall consistency

> +
> +#define REASONABLE_SIZE 1024
> +
> +static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
> +{
> +    Tile_context *tile = ctx->priv;
> +    int r;
> +    char dummy;
> +

> +    if (!args)
> +        return AVERROR(EINVAL);

Default size? Or tell the user what's wrong in this case.

> +    r = sscanf(args, "%u:%u%c", &tile->w, &tile->h, &dummy);
> +    if (r != 2 || !tile->w || !tile->h)
> +        return AVERROR(EINVAL);
> +    if (tile->w > REASONABLE_SIZE || tile->h > REASONABLE_SIZE) {
> +        av_log(ctx, AV_LOG_ERROR, "Tile size %ux%u is insane.\n",
> +               tile->w, tile->h);
> +        return AVERROR(EINVAL);
> +    }
> +    return 0;
> +}
> +
> +static int query_formats(AVFilterContext *ctx)
> +{
> +    avfilter_set_common_pixel_formats(ctx, ff_draw_supported_pixel_formats());
> +    return 0;
> +}
> +
> +static int config_props(AVFilterLink *outlink)
> +{
> +    AVFilterContext *ctx = outlink->src;
> +    Tile_context *tile   = ctx->priv;
> +    AVFilterLink *inlink = ctx->inputs[0];
> +
> +    if (inlink->w > INT_MAX / tile->w) {
> +        av_log(ctx, AV_LOG_ERROR, "Total width %ux%u is too much.\n",
> +               tile->w, inlink->w);
> +        return AVERROR(EINVAL);
> +    }
> +    if (inlink->h > INT_MAX / tile->h) {
> +        av_log(ctx, AV_LOG_ERROR, "Total height %ux%u is too much.\n",
> +               tile->h, inlink->h);
> +        return AVERROR(EINVAL);
> +    }
> +    outlink->w = tile->w * inlink->w;
> +    outlink->h = tile->h * inlink->h;
> +    outlink->sample_aspect_ratio = inlink->sample_aspect_ratio;
> +    ff_draw_init(&tile->draw, inlink->format, 0);

> +    /* TODO make the color an option, or find an unified way of choosing it */
> +    ff_draw_color(&tile->draw, &tile->blank, (uint8_t[]){ 0, 0, 0, -1 });

What's the problem with it?

> +
> +    return 0;
> +}
> +

> +/* Note: direct rendering is not possible since there is no guarantee that
> + * buffers are fed to start_frame in the order they were obtained from
> + * get_buffer (think B-frames). */

Is that true? I believed the decode API was taking care of it (return
decoded frames in presentation order)

[...]
> +AVFilter avfilter_vf_tile = {
> +    .name          = "tile",
> +    .description   = NULL_IF_CONFIG_SMALL("Tile several successive frames together."),
> +    .init          = init,
> +    .query_formats = query_formats,
> +    .priv_size     = sizeof(Tile_context),
> +    .inputs = (const AVFilterPad[]) {
> +        { .name        = "default",
> +          .type        = AVMEDIA_TYPE_VIDEO,
> +          .start_frame = start_frame,
> +          .draw_slice  = draw_slice,
> +          .end_frame   = end_frame,
> +          .min_perms   = AV_PERM_READ, },
> +        { .name = NULL }
> +    },
> +    .outputs = (const AVFilterPad[]) {
> +        { .name          = "default",
> +          .type          = AVMEDIA_TYPE_VIDEO,
> +          .config_props  = config_props,
> +          .request_frame = request_frame },
> +        { .name = NULL }
> +    },
> +};

Overall nice work, I wonder if it would make sense to add a setkey
filter for making this filter more useful.
-- 
FFmpeg = Fiendish and Fabulous Mortal Peaceless Evanescent Game