[FFmpeg-devel] [PATCH] Zoom & Pan filter

Stefano Sabatini stefasab at gmail.com
Thu Oct 31 13:19:04 CET 2013


On date Thursday 2013-10-31 10:04:30 +0000, Paul B Mahol encoded:
> Signed-off-by: Paul B Mahol <onemda at gmail.com>
> ---
>  doc/filters.texi         |  83 +++++++++++++
>  libavfilter/Makefile     |   1 +
>  libavfilter/allfilters.c |   1 +
>  libavfilter/vf_zopan.c   | 301 +++++++++++++++++++++++++++++++++++++++++++++++
>  4 files changed, 386 insertions(+)
>  create mode 100644 libavfilter/vf_zopan.c
> 
> diff --git a/doc/filters.texi b/doc/filters.texi
> index 14692a2..9ddf26e 100644
> --- a/doc/filters.texi
> +++ b/doc/filters.texi
> @@ -8195,6 +8195,89 @@ only deinterlace frames marked as interlaced
>  Default value is @code{all}.
>  @end table
>  
> + at section zopan
> +

Short description missing.

> +This filter accepts the following options:
> +
> + at table @option
> + at item z

> +Set the zoom expression, Default is 1.

, -> .

Also you could expand this and explain what's the meaning of the zoom
expression.


> +
> + at item x
> + at item y
> +Set the x and y expression. Default is 0.

Same, what are x and y?

> +
> + at item d
> +Set the duration expression in number of frames.
> +This sets for how many number of frames effect will last for
> +single input image.

Can't you use the enable expression for this?

> +
> + at item s
> +Set the output image size, default is 'hd720'.
> + at end table
> +
> +Each expression can contain the following constants:
> +
> + at table @option
> + at item in_w, iw
> +Input width.
> +
> + at item in_h, ih
> +Input height.
> +
> + at item out_w, ow
> +Output width.
> +
> + at item out_h, oh
> +Output height.
> +
> + at item in
> +Input frame count.
> +
> + at item on
> +Output frame count.
> +
> + at item x
> + at item y
> +Last calculated 'x' and 'y' position from 'x' and 'y' expression
> +for current input frame.
> +
> + at item px
> + at item py
> +'x' and 'y' of last output frame of previous input frame or 0 when there was
> +not yet such frame (first input frame).
> +
> + at item zoom
> +Last calculated zoom from 'z' expression for current input frame.
> +
> + at item pzoom
> +Last calculated zoom of last output frame of previous input frame.
> +

> + at item duration
> +Number of output frames for current input frame. Calculated from 'd' expression
> +for each input frame.

Confusing.

> +
> + at item pduration
> +Number of output frames created for previous input frame.
> +
> + at item sar
> +Sample aspect ratio
> +
> + at item dar
> +Display aspect ratio

nit: not complete sentences, you can consistently drop capitalization
and final point

> +
> + at end table
> +
> + at subsection Examples
> +
> + at itemize
> + at item
> +Zoom-in up to 1.5 and pan at same time to some spot near centre of picture:
> + at example
> +zopan=z=min(zoom+0.0015\,1.5):d=700:x=if(gte(zoom\,1.5)\,x\,x+1/a):y=if(gte(zoom\,1.5)\,y\,y+1):s=640x360"
> + at end example
> + at end itemize
> +
>  @c man end VIDEO FILTERS
>  
>  @chapter Video Sources
> diff --git a/libavfilter/Makefile b/libavfilter/Makefile
> index 3fcccf8..a108888 100644
> --- a/libavfilter/Makefile
> +++ b/libavfilter/Makefile
> @@ -211,6 +211,7 @@ OBJS-$(CONFIG_VIGNETTE_FILTER)               += vf_vignette.o
>  OBJS-$(CONFIG_W3FDIF_FILTER)                 += vf_w3fdif.o
>  OBJS-$(CONFIG_YADIF_FILTER)                  += vf_yadif.o
>  OBJS-$(CONFIG_ZMQ_FILTER)                    += f_zmq.o
> +OBJS-$(CONFIG_ZOPAN_FILTER)                  += vf_zopan.o
>  
>  OBJS-$(CONFIG_CELLAUTO_FILTER)               += vsrc_cellauto.o
>  OBJS-$(CONFIG_COLOR_FILTER)                  += vsrc_testsrc.o
> diff --git a/libavfilter/allfilters.c b/libavfilter/allfilters.c
> index a61ca0e..075503a 100644
> --- a/libavfilter/allfilters.c
> +++ b/libavfilter/allfilters.c
> @@ -206,6 +206,7 @@ void avfilter_register_all(void)
>      REGISTER_FILTER(W3FDIF,         w3fdif,         vf);
>      REGISTER_FILTER(YADIF,          yadif,          vf);
>      REGISTER_FILTER(ZMQ,            zmq,            vf);
> +    REGISTER_FILTER(ZOPAN,          zopan,          vf);
>  
>      REGISTER_FILTER(CELLAUTO,       cellauto,       vsrc);
>      REGISTER_FILTER(COLOR,          color,          vsrc);
> diff --git a/libavfilter/vf_zopan.c b/libavfilter/vf_zopan.c
> new file mode 100644
> index 0000000..6156192
> --- /dev/null
> +++ b/libavfilter/vf_zopan.c
> @@ -0,0 +1,301 @@
> +/*
> + * Copyright (c) 2013 Paul B Mahol
> + *
> + * 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/eval.h"
> +#include "libavutil/opt.h"
> +#include "libavutil/pixdesc.h"
> +#include "avfilter.h"
> +#include "formats.h"
> +#include "internal.h"
> +#include "video.h"
> +#include "libswscale/swscale.h"
> +
> +static const char *const var_names[] = {
> +    "in_w",   "iw",
> +    "in_h",   "ih",
> +    "out_w",  "ow",
> +    "out_h",  "oh",
> +    "in",
> +    "on",
> +    "duration",
> +    "pduration",
> +    "frame",
> +    "zoom",
> +    "pzoom",
> +    "x", "px",
> +    "y", "py",
> +    "a",
> +    "sar",
> +    "dar",
> +    "hsub",
> +    "vsub",
> +    NULL
> +};

time would also be useful

> +
> +enum var_name {
> +    VAR_IN_W,   VAR_IW,
> +    VAR_IN_H,   VAR_IH,
> +    VAR_OUT_W,  VAR_OW,
> +    VAR_OUT_H,  VAR_OH,
> +    VAR_IN,
> +    VAR_ON,
> +    VAR_DURATION,
> +    VAR_PDURATION,
> +    VAR_FRAME,
> +    VAR_ZOOM,
> +    VAR_PZOOM,
> +    VAR_X, VAR_PX,
> +    VAR_Y, VAR_PY,
> +    VAR_A,
> +    VAR_SAR,
> +    VAR_DAR,
> +    VAR_HSUB,
> +    VAR_VSUB,
> +    VARS_NB
> +};
> +
> +typedef struct ZPcontext {
> +    const AVClass *class;
> +    char *zoom_expr_str;
> +    char *x_expr_str;
> +    char *y_expr_str;
> +    char *duration_expr_str;
> +    int w, h;
> +    double x, y;
> +    double prev_zoom;
> +    int prev_nb_frames;
> +    struct SwsContext *sws;
> +    int64_t frame_count;
> +} ZPContext;
> +
> +#define OFFSET(x) offsetof(ZPContext, x)
> +#define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
> +static const AVOption zopan_options[] = {
> +    { "z", "set the zoom expression", OFFSET(zoom_expr_str), AV_OPT_TYPE_STRING, {.str = "1" }, .flags = FLAGS },
> +    { "x", "set the x expression", OFFSET(x_expr_str), AV_OPT_TYPE_STRING, {.str="0"}, .flags = FLAGS },
> +    { "y", "set the y expression", OFFSET(y_expr_str), AV_OPT_TYPE_STRING, {.str="0"}, .flags = FLAGS },
> +    { "d", "set the duration expression", OFFSET(duration_expr_str), AV_OPT_TYPE_STRING, {.str="90"}, .flags = FLAGS },
> +    { "s", "set the output image size", OFFSET(w), AV_OPT_TYPE_IMAGE_SIZE, {.str="hd720"}, .flags = FLAGS },
> +    { NULL }
> +};
> +
> +AVFILTER_DEFINE_CLASS(zopan);
> +
> +static av_cold int init(AVFilterContext *ctx)
> +{
> +    ZPContext *s = ctx->priv;
> +
> +    s->prev_zoom = 1;
> +    return 0;
> +}
> +
> +static int config_output(AVFilterLink *outlink)
> +{
> +    AVFilterContext *ctx = outlink->src;
> +    ZPContext *s = ctx->priv;
> +
> +    outlink->w = s->w;
> +    outlink->h = s->h;
> +
> +    return 0;
> +}
> +
> +static int filter_frame(AVFilterLink *inlink, AVFrame *in)
> +{
> +    AVFilterContext *ctx = inlink->dst;
> +    AVFilterLink *outlink = ctx->outputs[0];

> +    ZPContext *s= ctx->priv;

nit: *s_ =

> +    double var_values[VARS_NB], nb_frames, zoom, dx, dy;
> +    const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(in->format);
> +    AVFrame *out;
> +    int i, k, x, y, w, h, ret = 0;
> +
> +    var_values[VAR_IN_W]  = var_values[VAR_IW] = in->width;
> +    var_values[VAR_IN_H]  = var_values[VAR_IH] = in->height;
> +    var_values[VAR_OUT_W] = var_values[VAR_OW] = s->w;
> +    var_values[VAR_OUT_H] = var_values[VAR_OH] = s->h;
> +    var_values[VAR_IN]    = inlink->frame_count + 1;
> +    var_values[VAR_ON]    = outlink->frame_count + 1;
> +    var_values[VAR_PX]    = s->x;
> +    var_values[VAR_PY]    = s->y;
> +    var_values[VAR_X]     = 0;
> +    var_values[VAR_Y]     = 0;
> +    var_values[VAR_PZOOM] = s->prev_zoom;
> +    var_values[VAR_ZOOM]  = 1;
> +    var_values[VAR_PDURATION] = s->prev_nb_frames;
> +    var_values[VAR_A]     = (double) in->width / in->height;
> +    var_values[VAR_SAR]   = inlink->sample_aspect_ratio.num ?
> +        (double) inlink->sample_aspect_ratio.num / inlink->sample_aspect_ratio.den : 1;
> +    var_values[VAR_DAR]   = var_values[VAR_A] * var_values[VAR_SAR];
> +    var_values[VAR_HSUB]  = 1 << desc->log2_chroma_w;
> +    var_values[VAR_VSUB]  = 1 << desc->log2_chroma_h;

having a time variable seems useful

> +
> +    if ((ret = av_expr_parse_and_eval(&nb_frames, s->duration_expr_str,
> +                                      var_names, var_values,
> +                                      NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0)
> +        goto fail;
> +
> +    var_values[VAR_DURATION] = nb_frames;
> +    for (i = 0; i < nb_frames; i++) {
> +        int px[4];
> +        int py[4];
> +
> +        var_values[VAR_FRAME] = i;
> +        var_values[VAR_ON] = outlink->frame_count + 1;
> +        if ((ret = av_expr_parse_and_eval(&zoom, s->zoom_expr_str,
> +                                          var_names, var_values,
> +                                          NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0)
> +            goto fail;
> +
> +        zoom = av_clipd(zoom, 1, 10);
> +        var_values[VAR_ZOOM] = zoom;
> +        w = in->width * (1.0 / zoom);
> +        h = in->height * (1.0 / zoom);
> +
> +        if ((ret = av_expr_parse_and_eval(&dx, s->x_expr_str,
> +                                          var_names, var_values,
> +                                          NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0)
> +            goto fail;
> +        x = dx = av_clipd(dx, 0, FFMAX(in->width - w, 0));
> +        var_values[VAR_X] = dx;
> +        x &= ~((1 << desc->log2_chroma_w) - 1);
> +
> +        if ((ret = av_expr_parse_and_eval(&dy, s->y_expr_str,
> +                                          var_names, var_values,
> +                                          NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0)
> +            goto fail;
> +        y = dy = av_clipd(dy, 0, FFMAX(in->height - h, 0));
> +        var_values[VAR_Y] = dy;
> +        y &= ~((1 << desc->log2_chroma_h) - 1);
> +
> +        out = ff_get_video_buffer(outlink, outlink->w, outlink->h);
> +        if (!out) {
> +            ret = AVERROR(ENOMEM);
> +            goto fail;
> +        }
> +
> +        px[1] = px[2] = FF_CEIL_RSHIFT(x, desc->log2_chroma_w);
> +        px[0] = px[3] = x;
> +
> +        py[1] = py[2] = FF_CEIL_RSHIFT(y, desc->log2_chroma_h);
> +        py[0] = py[3] = y;
> +
> +        s->sws = sws_alloc_context();
> +        if (!s->sws) {
> +            ret = AVERROR(ENOMEM);
> +            goto fail;
> +        }
> +
> +        uint8_t *input[4];
> +
> +        for (k = 0; in->data[k]; k++)
> +            input[k] = in->data[k] + py[k] * in->linesize[k] + px[k];
> +
> +        av_opt_set_int(s->sws, "srcw", w, 0);
> +        av_opt_set_int(s->sws, "srch", h, 0);
> +        av_opt_set_int(s->sws, "src_format", in->format, 0);
> +        av_opt_set_int(s->sws, "dstw", outlink->w, 0);
> +        av_opt_set_int(s->sws, "dsth", outlink->h, 0);
> +        av_opt_set_int(s->sws, "dst_format", outlink->format, 0);
> +        av_opt_set_int(s->sws, "sws_flags", SWS_BICUBIC, 0);
> +
> +        if ((ret = sws_init_context(s->sws, NULL, NULL)) < 0)
> +            goto fail;

what about reusing the same context and updating it in case of changes?

> +
> +        sws_scale(s->sws, (const uint8_t *const *)&input, in->linesize, 0, h, out->data, out->linesize);
> +
> +        out->pts = av_rescale_q(in->pts, inlink->time_base,
> +                                outlink->time_base) + s->frame_count;
> +        s->frame_count++;
> +
> +        ret = ff_filter_frame(outlink, out);
> +        if (ret < 0)
> +            break;
> +
> +        sws_freeContext(s->sws);
> +        s->sws = NULL;
> +    }
> +
> +    s->x = dx;
> +    s->y = dy;
> +    s->prev_zoom = zoom;
> +    s->prev_nb_frames = nb_frames;
> +
> +fail:
> +    sws_freeContext(s->sws);
> +    s->sws = NULL;
> +    av_frame_free(&in);
> +    return ret;
> +}
> +
> +static int query_formats(AVFilterContext *ctx)
> +{
> +    static const enum AVPixelFormat pix_fmts[] = {
> +        AV_PIX_FMT_YUV444P,  AV_PIX_FMT_YUV422P,
> +        AV_PIX_FMT_YUV420P,  AV_PIX_FMT_YUV411P,
> +        AV_PIX_FMT_YUV410P,  AV_PIX_FMT_YUV440P,
> +        AV_PIX_FMT_YUVA444P, AV_PIX_FMT_YUVA422P,
> +        AV_PIX_FMT_YUVA420P,
> +        AV_PIX_FMT_YUVJ444P, AV_PIX_FMT_YUVJ440P,
> +        AV_PIX_FMT_YUVJ422P, AV_PIX_FMT_YUVJ420P,
> +        AV_PIX_FMT_YUVJ411P,
> +        AV_PIX_FMT_GRAY8,
> +        AV_PIX_FMT_NONE
> +    };
> +
> +
> +    ff_set_common_formats(ctx, ff_make_format_list(pix_fmts));
> +    return 0;
> +}
> +
> +static av_cold void uninit(AVFilterContext *ctx)
> +{
> +}
> +
> +static const AVFilterPad inputs[] = {
> +    {
> +        .name         = "default",
> +        .type         = AVMEDIA_TYPE_VIDEO,
> +        .filter_frame = filter_frame,
> +    },
> +    { NULL }
> +};
> +
> +static const AVFilterPad outputs[] = {
> +    {
> +        .name          = "default",
> +        .type          = AVMEDIA_TYPE_VIDEO,
> +        .config_props  = config_output,
> +    },
> +    { NULL }
> +};
> +
> +AVFilter avfilter_vf_zopan = {
> +    .name          = "zopan",

> +    .description   = NULL_IF_CONFIG_SMALL("Zoom & Pan."),

Apply Zoom & Pan effect.

[...]
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