libavfilter/vf_removelogo.c

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/*
 * Copyright (c) 2005 Robert Edele <yartrebo@earthlink.net>
 * Copyright (c) 2012 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
 */

#include "libavutil/imgutils.h"
#include "avfilter.h"
#include "bbox.h"
#include "lavfutils.h"
#include "lswsutils.h"

typedef struct {
    /* Stores our collection of masks. The first is for an array of
       the second for the y axis, and the third for the x axis. */
    int ***mask;
    int max_mask_size;
    int mask_w, mask_h;

    uint8_t      *full_mask_data;
    FFBoundingBox full_mask_bbox;
    uint8_t      *half_mask_data;
    FFBoundingBox half_mask_bbox;
} RemovelogoContext;

#define apply_mask_fudge_factor(x) (((x) >> 2) + x)

static void convert_mask_to_strength_mask(uint8_t *data, int linesize,
                                          int w, int h, int min_val,
                                          int *max_mask_size)
{
    int x, y;

    /* How many times we've gone through the loop. Used in the
       in-place erosion algorithm and to get us max_mask_size later on. */
    int current_pass = 0;

    /* set all non-zero values to 1 */
    for (y = 0; y < h; y++)
        for (x = 0; x < w; x++)
            data[y*linesize + x] = data[y*linesize + x] > min_val;

    /* For each pass, if a pixel is itself the same value as the
       current pass, and its four neighbors are too, then it is
       incremented. If no pixels are incremented by the end of the
       pass, then we go again. Edge pixels are counted as always
       excluded (this should be true anyway for any sane mask, but if
       it isn't this will ensure that we eventually exit). */
    while (1) {
        /* If this doesn't get set by the end of this pass, then we're done. */
        int has_anything_changed = 0;
        uint8_t *current_pixel0 = data, *current_pixel;
        current_pass++;

        for (y = 1; y < h-1; y++) {
            current_pixel = current_pixel0;
            for (x = 1; x < w-1; x++) {
                /* Apply the in-place erosion transform. It is based
                   on the following two premises:
                   1 - Any pixel that fails 1 erosion will fail all
                       future erosions.

                   2 - Only pixels having survived all erosions up to
                       the present will be >= to current_pass.
                   It doesn't matter if it survived the current pass,
                   failed it, or hasn't been tested yet.  By using >=
                   instead of ==, we allow the algorithm to work in
                   place. */
                if ( *current_pixel      >= current_pass &&
                    *(current_pixel + 1) >= current_pass &&
                    *(current_pixel - 1) >= current_pass &&
                    *(current_pixel + w) >= current_pass &&
                    *(current_pixel - w) >= current_pass) {
                    /* Increment the value since it still has not been
                     * eroded, as evidenced by the if statement that
                     * just evaluated to true. */
                    (*current_pixel)++;
                    has_anything_changed = 1;
                }
                current_pixel++;
            }
            current_pixel0 += linesize;
        }
        if (!has_anything_changed)
            break;
    }

    /* Apply the fudge factor, which will increase the size of the
     * mask a little to reduce jitter at the cost of more blur. */
    for (y = 1; y < h - 1; y++)
        for (x = 1; x < w - 1; x++)
            data[(y * linesize) + x] = apply_mask_fudge_factor(data[(y * linesize) + x]);

    /* As a side-effect, we now know the maximum mask size, which
     * we'll use to generate our masks. */
    /* Apply the fudge factor to this number too, since we must ensure
     * that enough masks are generated. */
    *max_mask_size = apply_mask_fudge_factor(current_pass + 1);
}

static int query_formats(AVFilterContext *ctx)
{
    enum PixelFormat pix_fmts[] = { PIX_FMT_YUV420P, PIX_FMT_NONE };
    avfilter_set_common_pixel_formats(ctx, avfilter_make_format_list(pix_fmts));
    return 0;
}

static int load_mask(uint8_t **mask, int *w, int *h,
                     const char *filename, void *log_ctx)
{
    int ret;
    enum PixelFormat pix_fmt;
    uint8_t *src_data[4], *gray_data[4];
    int src_linesize[4], gray_linesize[4];

    /* load image from file */
    if ((ret = ff_load_image(src_data, src_linesize, w, h, &pix_fmt, filename, log_ctx)) < 0)
        return ret;

    /* convert the image to GRAY8 */
    if ((ret = ff_scale_image(gray_data, gray_linesize, *w, *h, PIX_FMT_GRAY8,
                              src_data, src_linesize, *w, *h, pix_fmt,
                              log_ctx)) < 0)
        goto end;

    /* copy mask to a newly allocated array */
    *mask = av_malloc(*w * *h);
    if (!*mask)
        ret = AVERROR(ENOMEM);
    av_image_copy_plane(*mask, *w, gray_data[0], gray_linesize[0], *w, *h);

end:
    av_free(src_data[0]);
    av_free(gray_data[0]);
    return ret;
}

static void generate_half_size_image(const uint8_t *src_data, int src_linesize,
                                     uint8_t *dst_data, int dst_linesize,
                                     int src_w, int src_h,
                                     int *max_mask_size)
{
    int x, y;

    /* Copy over the image data, using the average of 4 pixels for to
     * calculate each downsampled pixel. */
    for (y = 0; y < src_h/2; y++) {
        for (x = 0; x < src_w/2; x++) {
            /* Set the pixel if there exists a non-zero value in the
             * source pixels, else clear it. */
            dst_data[(y * dst_linesize) + x] =
                src_data[((y << 1) * src_linesize) + (x << 1)] ||
                src_data[((y << 1) * src_linesize) + (x << 1) + 1] ||
                src_data[(((y << 1) + 1) * src_linesize) + (x << 1)] ||
                src_data[(((y << 1) + 1) * src_linesize) + (x << 1) + 1];
            dst_data[(y * dst_linesize) + x] = FFMIN(1, dst_data[(y * dst_linesize) + x]);
        }
    }

    convert_mask_to_strength_mask(dst_data, dst_linesize,
                                  src_w/2, src_h/2, 0, max_mask_size);
}

static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
{
    RemovelogoContext *removelogo = ctx->priv;
    int ***mask;
    int ret = 0;
    int a, b, c, w, h;
    int full_max_mask_size, half_max_mask_size;

    if (!args) {
        av_log(ctx, AV_LOG_ERROR, "An image file must be specified as argument\n");
        return AVERROR(EINVAL);
    }

    /* Load our mask image. */
    if ((ret = load_mask(&removelogo->full_mask_data, &w, &h, args, ctx)) < 0)
        return ret;
    removelogo->mask_w = w;
    removelogo->mask_h = h;

    convert_mask_to_strength_mask(removelogo->full_mask_data, w, w, h,
                                  16, &full_max_mask_size);

    /* Create the scaled down mask image for the chroma planes. */
    if (!(removelogo->half_mask_data = av_mallocz(w/2 * h/2)))
        return AVERROR(ENOMEM);
    generate_half_size_image(removelogo->full_mask_data, w,
                             removelogo->half_mask_data, w/2,
                             w, h, &half_max_mask_size);

    removelogo->max_mask_size = FFMAX(full_max_mask_size, half_max_mask_size);

    /* Create a circular mask for each size up to max_mask_size. When
       the filter is applied, the mask size is determined on a pixel
       by pixel basis, with pixels nearer the edge of the logo getting
       smaller mask sizes. */
    mask = (int ***)av_malloc(sizeof(int **) * (removelogo->max_mask_size + 1));
    if (!mask)
        return AVERROR(ENOMEM);

    for (a = 0; a <= removelogo->max_mask_size; a++) {
        mask[a] = (int **)av_malloc(sizeof(int *) * ((a * 2) + 1));
        if (!mask[a])
            return AVERROR(ENOMEM);
        for (b = -a; b <= a; b++) {
            mask[a][b + a] = (int *)av_malloc(sizeof(int) * ((a * 2) + 1));
            if (!mask[a][b + a])
                return AVERROR(ENOMEM);
            for (c = -a; c <= a; c++) {
                if ((b * b) + (c * c) <= (a * a)) /* Circular 0/1 mask. */
                    mask[a][b + a][c + a] = 1;
                else
                    mask[a][b + a][c + a] = 0;
            }
        }
    }
    removelogo->mask = mask;

    /* Calculate our bounding rectangles, which determine in what
     * region the logo resides for faster processing. */
    ff_calculate_bounding_box(&removelogo->full_mask_bbox, removelogo->full_mask_data, w, w, h, 0);
    ff_calculate_bounding_box(&removelogo->half_mask_bbox, removelogo->half_mask_data, w/2, w/2, h/2, 0);

#define SHOW_LOGO_INFO(mask_type)                                       \
    av_log(ctx, AV_LOG_INFO, #mask_type " x1:%d x2:%d y1:%d y2:%d max_mask_size:%d\n", \
           removelogo->mask_type##_mask_bbox.x1, removelogo->mask_type##_mask_bbox.x2, \
           removelogo->mask_type##_mask_bbox.y1, removelogo->mask_type##_mask_bbox.y2, \
           mask_type##_max_mask_size);
    SHOW_LOGO_INFO(full);
    SHOW_LOGO_INFO(half);

    return 0;
}

static int config_props_input(AVFilterLink *inlink)
{
    AVFilterContext *ctx = inlink->dst;
    RemovelogoContext *removelogo = ctx->priv;

    if (inlink->w != removelogo->mask_w || inlink->h != removelogo->mask_h) {
        av_log(ctx, AV_LOG_INFO,
               "Mask image size %dx%d does not match with the input video size %dx%d\n",
               removelogo->mask_w, removelogo->mask_h, inlink->w, inlink->h);
        return AVERROR(EINVAL);
    }

    return 0;
}

static unsigned int blur_pixel(int ***mask,
                               const uint8_t *mask_data, int mask_linesize,
                               uint8_t       *image_data, int image_linesize,
                               int w, int h, int x, int y)
{
    /* Mask size tells how large a circle to use. The radius is about
     * (slightly larger than) mask size. */
    int mask_size;
    int start_posx, start_posy, end_posx, end_posy;
    int i, j;
    unsigned int accumulator = 0, divisor = 0;
    /* What pixel we are reading out of the circular blur mask. */
    const uint8_t *image_read_position;
    /* What pixel we are reading out of the filter image. */
    const uint8_t *mask_read_position;

    /* Prepare our bounding rectangle and clip it if need be. */
    mask_size  = mask_data[y * mask_linesize + x];
    start_posx = FFMAX(0, x - mask_size);
    start_posy = FFMAX(0, y - mask_size);
    end_posx   = FFMIN(w - 1, x + mask_size);
    end_posy   = FFMIN(h - 1, y + mask_size);

    image_read_position = image_data + image_linesize * start_posy + start_posx;
    mask_read_position  = mask_data  + mask_linesize  * start_posy + start_posx;

    for (j = start_posy; j <= end_posy; j++) {
        for (i = start_posx; i <= end_posx; i++) {
            /* Check if this pixel is in the mask or not. Only use the
             * pixel if it is not. */
            if (!(*mask_read_position) && mask[mask_size][i - start_posx][j - start_posy]) {
                accumulator += *image_read_position;
                divisor++;
            }

            image_read_position++;
            mask_read_position++;
        }

        image_read_position += (image_linesize - ((end_posx + 1) - start_posx));
        mask_read_position  += (mask_linesize - ((end_posx + 1) - start_posx));
    }

    /* If divisor is 0, it means that not a single pixel is outside of
       the logo, so we have no data.  Else we need to normalise the
       data using the divisor. */
    return divisor == 0 ? 255:
        (accumulator + (divisor / 2)) / divisor;  /* divide, taking into account average rounding error */
}

static void blur_image(int ***mask,
                       const uint8_t *src_data,  int src_linesize,
                             uint8_t *dst_data,  int dst_linesize,
                       const uint8_t *mask_data, int mask_linesize,
                       int w, int h, int direct,
                       FFBoundingBox *bbox)
{
    int x, y;
    uint8_t *dst_line;
    const uint8_t *src_line;

    if (!direct)
        av_image_copy_plane(dst_data, dst_linesize, src_data, src_linesize, w, h);

    for (y = bbox->y1; y <= bbox->y2; y++) {
        src_line = src_data + src_linesize * y;
        dst_line = dst_data + dst_linesize * y;

        for (x = bbox->x1; x <= bbox->x2; x++) {
             if (mask_data[y * mask_linesize + x]) {
                /* Only process if we are in the mask. */
                 dst_line[x] = blur_pixel(mask,
                                          mask_data, mask_linesize,
                                          dst_data, dst_linesize,
                                          w, h, x, y);
            } else {
                /* Else just copy the data. */
                if (!direct)
                    dst_line[x] = src_line[x];
            }
        }
    }
}

static void start_frame(AVFilterLink *inlink, AVFilterBufferRef *inpicref)
{
    AVFilterLink *outlink = inlink->dst->outputs[0];
    AVFilterBufferRef *outpicref;

    if (inpicref->perms & AV_PERM_PRESERVE) {
        outpicref = avfilter_get_video_buffer(outlink, AV_PERM_WRITE,
                                              outlink->w, outlink->h);
        avfilter_copy_buffer_ref_props(outpicref, inpicref);
        outpicref->video->w = outlink->w;
        outpicref->video->h = outlink->h;
    } else
        outpicref = inpicref;

    outlink->out_buf = outpicref;
    avfilter_start_frame(outlink, avfilter_ref_buffer(outpicref, ~0));
}

static void end_frame(AVFilterLink *inlink)
{
    RemovelogoContext *removelogo = inlink->dst->priv;
    AVFilterLink *outlink = inlink->dst->outputs[0];
    AVFilterBufferRef *inpicref  = inlink ->cur_buf;
    AVFilterBufferRef *outpicref = outlink->out_buf;
    int direct = inpicref == outpicref;

    blur_image(removelogo->mask,
               inpicref ->data[0], inpicref ->linesize[0],
               outpicref->data[0], outpicref->linesize[0],
               removelogo->full_mask_data, inlink->w,
               inlink->w, inlink->h, direct, &removelogo->full_mask_bbox);
    blur_image(removelogo->mask,
               inpicref ->data[1], inpicref ->linesize[1],
               outpicref->data[1], outpicref->linesize[1],
               removelogo->half_mask_data, inlink->w/2,
               inlink->w/2, inlink->h/2, direct, &removelogo->half_mask_bbox);
    blur_image(removelogo->mask,
               inpicref ->data[2], inpicref ->linesize[2],
               outpicref->data[2], outpicref->linesize[2],
               removelogo->half_mask_data, inlink->w/2,
               inlink->w/2, inlink->h/2, direct, &removelogo->half_mask_bbox);

    avfilter_draw_slice(outlink, 0, inlink->h, 1);
    avfilter_end_frame(outlink);
    avfilter_unref_buffer(inpicref);
    if (!direct)
        avfilter_unref_buffer(outpicref);
}

static void uninit(AVFilterContext *ctx)
{
    RemovelogoContext *removelogo = ctx->priv;
    int a, b;

    av_freep(&removelogo->full_mask_data);
    av_freep(&removelogo->half_mask_data);

    if (removelogo->mask) {
        /* Loop through each mask. */
        for (a = 0; a <= removelogo->max_mask_size; a++) {
            /* Loop through each scanline in a mask. */
            for (b = -a; b <= a; b++) {
                av_free(removelogo->mask[a][b + a]); /* Free a scanline. */
            }
            av_free(removelogo->mask[a]);
        }
        /* Free the array of pointers pointing to the masks. */
        av_freep(&removelogo->mask);
    }
}

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

AVFilter avfilter_vf_removelogo = {
    .name          = "removelogo",
    .description   = NULL_IF_CONFIG_SMALL("Remove a TV logo based on a mask image."),
    .priv_size     = sizeof(RemovelogoContext),
    .init          = init,
    .uninit        = uninit,
    .query_formats = query_formats,

    .inputs = (const AVFilterPad[]) {
        { .name             = "default",
          .type             = AVMEDIA_TYPE_VIDEO,
          .get_video_buffer = avfilter_null_get_video_buffer,
          .config_props     = config_props_input,
          .draw_slice       = null_draw_slice,
          .start_frame      = start_frame,
          .end_frame        = end_frame,
          .min_perms        = AV_PERM_WRITE | AV_PERM_READ,
          .rej_perms        = AV_PERM_PRESERVE },
        { .name = NULL }
    },
    .outputs = (const AVFilterPad[]) {
        { .name             = "default",
          .type             = AVMEDIA_TYPE_VIDEO, },
        { .name = NULL }
    },
};

---