remove_logo filter by yartrebo, committed with fixes for c++ variable declarations

git-svn-id: svn://svn.mplayerhq.hu/mplayer/trunk@15694 b3059339-0415-0410-9bf9-f77b7e298cf2

2 files changed, 912 insertions, 1 deletions

diff --git a/libmpcodecs/Makefile b/libmpcodecs/Makefile
index 9928116bc0..8c5da23037 100644
--- a/libmpcodecs/Makefile
+++ b/libmpcodecs/Makefile
@@ -14,7 +14,7 @@ VIDEO_SRCS_NAT=vd_null.c vd_raw.c vd_hmblck.c vd_mpegpes.c vd_mtga.c vd_sgi.c
 VIDEO_SRCS_OPT=vd_realvid.c vd_ffmpeg.c vd_dshow.c vd_dmo.c vd_vfw.c vd_vfwex.c vd_odivx.c vd_divx4.c vd_zrmjpeg.c vd_xanim.c vd_xvid.c vd_xvid4.c vd_libdv.c vd_qtvideo.c vd_theora.c
 VIDEO_SRCS=dec_video.c vd.c $(VIDEO_SRCS_NAT) $(VIDEO_SRCS_LIB) $(VIDEO_SRCS_OPT)
 
-VFILTER_SRCS=vf.c vf_vo.c vf_crop.c vf_expand.c vf_scale.c vf_format.c vf_noformat.c vf_yuy2.c vf_flip.c vf_rgb2bgr.c vf_rotate.c vf_mirror.c vf_palette.c vf_lavc.c vf_dvbscale.c vf_cropdetect.c vf_test.c vf_noise.c vf_yvu9.c vf_rectangle.c vf_lavcdeint.c vf_eq.c vf_eq2.c vf_halfpack.c vf_dint.c vf_1bpp.c vf_bmovl.c vf_2xsai.c vf_unsharp.c vf_swapuv.c vf_il.c vf_boxblur.c vf_sab.c vf_smartblur.c vf_perspective.c vf_down3dright.c vf_field.c vf_denoise3d.c vf_hqdn3d.c vf_detc.c vf_telecine.c vf_tfields.c vf_ivtc.c vf_ilpack.c vf_dsize.c vf_decimate.c vf_softpulldown.c vf_tinterlace.c vf_pullup.c pullup.c vf_framestep.c vf_tile.c vf_delogo.c vf_fil.c vf_hue.c vf_spp.c vf_fspp.c vf_yuvcsp.c vf_filmdint.c vf_kerndeint.c vf_rgbtest.c vf_qp.c vf_phase.c vf_divtc.c vf_harddup.c vf_softskip.c
+VFILTER_SRCS=vf.c vf_vo.c vf_crop.c vf_expand.c vf_scale.c vf_format.c vf_noformat.c vf_yuy2.c vf_flip.c vf_rgb2bgr.c vf_rotate.c vf_mirror.c vf_palette.c vf_lavc.c vf_dvbscale.c vf_cropdetect.c vf_test.c vf_noise.c vf_yvu9.c vf_rectangle.c vf_lavcdeint.c vf_eq.c vf_eq2.c vf_halfpack.c vf_dint.c vf_1bpp.c vf_bmovl.c vf_2xsai.c vf_unsharp.c vf_swapuv.c vf_il.c vf_boxblur.c vf_sab.c vf_smartblur.c vf_perspective.c vf_down3dright.c vf_field.c vf_denoise3d.c vf_hqdn3d.c vf_detc.c vf_telecine.c vf_tfields.c vf_ivtc.c vf_ilpack.c vf_dsize.c vf_decimate.c vf_softpulldown.c vf_tinterlace.c vf_pullup.c pullup.c vf_framestep.c vf_tile.c vf_delogo.c vf_fil.c vf_hue.c vf_spp.c vf_fspp.c vf_yuvcsp.c vf_filmdint.c vf_kerndeint.c vf_rgbtest.c vf_qp.c vf_phase.c vf_divtc.c vf_harddup.c vf_softskip.c vf_remove_logo.c
 ifeq ($(HAVE_FFPOSTPROCESS),yes)
 VFILTER_SRCS += vf_pp.c
 endif
diff --git a/libmpcodecs/vf_remove_logo.c b/libmpcodecs/vf_remove_logo.c
new file mode 100644
index 0000000000..b917326950
--- /dev/null
+++ b/libmpcodecs/vf_remove_logo.c
@@ -0,0 +1,911 @@
+/*
+Copyright 2005 Robert Edele.
+
+e-mail: yartrebo@earthlink.net
+
+This program is free software; you can redistribute it and/or modify it
+under the terms of the GNU General Public License as published by the Free
+Software Foundation; either version 2 of the License, or (at your option)
+any later version.
+
+This program 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 Public License for more
+details.
+
+You should have reveived a copy of the GNU General Public License
+along with this program; if not, write to the
+Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+02111-1307 USA
+
+__________________________________________________________________________
+| Robert Edele                                           Fri. 4-Feb-2005 |
+| This program loads a .pgm mask file showing where a logo is and uses   |
+| a blur transform to remove the logo.                                   |
+|________________________________________________________________________|
+*/
+
+/**
+ * \file vf_remove_logo.c
+ * 
+ * \brief Advanced blur-based logo removing filter.
+
+ *     Hello and welcome. This code implements a filter to remove annoying TV
+ * logos and other annoying images placed onto a video stream. It works by filling
+ * in the pixels that comprise the logo with neighboring pixels. The transform is
+ * very loosely based on a gaussian blur, but it is different enough to merit its
+ * own paragraph later on. It is a major improvement on the old delogo filter as
+ * it both uses a better blurring algorithm and uses a bitmap to use an arbitrary
+ * and generally much tighter fitting shape than a rectangle.
+ *
+ *     The filter requires 1 argument and has no optional arguments. It requires
+ * a filter bitmap, which must be in PGM or PPM format. A sample invocation would
+ * be -vf remove_logo=/home/username/logo_bitmaps/xyz.pgm.  Pixels with a value of
+ * zero are not part of the logo, and non-zero pixels are part of the logo. If you
+ * use white (255) for the logo and black (0) for the rest, you will be safe. For
+ * making the filter bitmap, I recommend taking a screen capture of a black frame
+ * with the logo visible, and then using The GIMP's threshold filter followed by
+ * the erode filter once or twice. If needed, little splotches can be fixed
+ * manually. Remember that if logo pixels are not covered, the filter quality will
+ * be much reduced. Marking too many pixels as part of the logo doesn't hurt as
+ * much, but it will increase the amount of blurring needed to cover over the
+ * image and will destroy more information than necessary. Additionally, this blur
+ * algorithm is O(n) = n^4, where n is the width and height of a hypothetical
+ * square logo, so extra pixels will slow things down on a large lo
+ *
+ *     The logo removal algorithm has two key points. The first is that it
+ * distinguishes between pixels in the logo and those not in the logo by using the
+ * passed-in bitmap. Pixels not in the logo are copied over directly without being
+ * modified and they also serve as source pixels for the logo fill-in. Pixels
+ * inside the logo have the mask applied.
+ *
+ *     At init-time the bitmap is reprocessed internally, and the distance to the
+ * nearest edge of the logo (Manhattan distance), along with a little extra to
+ * remove rough edges, is stored in each pixel. This is done using an in-place
+ * erosion algorithm, and incrementing each pixel that survives any given erosion.
+ * Once every pixel is eroded, the maximum value is recorded, and a set of masks
+ * from size 0 to this size are generaged. The masks are circular binary masks,
+ * where each pixel within a radius N (where N is the size of the mask) is a 1,
+ * and all other pixels are a 0. Although a gaussian mask would be more
+ * mathematically accurate, a binary mask works better in practice because we
+ * generally do not use the central pixels in the mask (because they are in the
+ * logo region), and thus a gaussian mask will cause too little blur and thus a
+ * very unstable image.
+ *
+ *     The mask is applied in a special way. Namely, only pixels in the mask that
+ * line up to pixels outside the logo are used. The dynamic mask size means that
+ * the mask is just big enough so that the edges touch pixels outside the logo, so
+ * the blurring is kept to a minimum and at least the first boundary condition is
+ * met (that the image function itself is continuous), even if the second boundary
+ * condition (that the derivative of the image function is continuous) is not met.
+ * A masking algorithm that does preserve the second boundary coundition
+ * (perhaps something based on a highly-modified bi-cubic algorithm) should offer
+ * even better results on paper, but the noise in a typical TV signal should make
+ * anything based on derivatives hopelessly noisy.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <inttypes.h>
+
+#include "../config.h"
+#include "../mp_msg.h"
+#include "../libvo/fastmemcpy.h"
+
+#include "img_format.h"
+#include "mp_image.h"
+#include "vf.h"
+
+//===========================================================================//
+
+/** \brief Returns the larger of the two arguments. **/
+#define max(x,y) ((x)>(y)?(x):(y))
+/** \brief Returns the smaller of the two arguments. **/
+#define min(x,y) ((x)>(y)?(y):(x))
+
+/**
+ * \brief Test if a pixel is part of the logo.
+ */
+#define test_filter(image, x, y) ((unsigned char) (image->pixel[((y) * image->width) + (x)]))
+
+/**
+ * \brief Chooses a slightly larger mask size to improve performance.
+ *
+ * This function maps the absolute minimum mask size needed to the mask size we'll
+ * actually use. f(x) = x (the smallest that will work) will produce the sharpest
+ * results, but will be quite jittery. f(x) = 1.25x (what I'm using) is a good
+ * tradeoff in my opinion. This will calculate only at init-time, so you can put a
+ * long expression here without effecting performance.
+ */
+#define apply_mask_fudge_factor(x) (((x) >> 2) + x)
+
+/**
+ * \brief Simple implementation of the PGM image format.
+ *
+ * This struct holds a bare-bones image loaded from a PGM or PPM file. Once
+ * loaded and pre-processed, each pixel in this struct will contain how far from
+ * the edge of the logo each pixel is, using the manhattan distance (|dx| + |dy|).
+ *
+ * pixels in char * pixel can be addressed using (y * width) + height.
+ */
+typedef struct
+{
+  unsigned short int width;
+  unsigned short int height;
+
+  unsigned char * pixel;
+
+} pgm_structure;
+
+/**
+ * \brief Stores persistant variables.
+ *
+ * Variables stored here are kept from frame to frame, and seperate instances of
+ * the filter will get their own seperate copies.
+ */
+typedef struct
+{
+  unsigned int fmt; /* Not exactly sure of the use for this. It came with the example filter I used as a basis for this, and it looks like a lot of stuff will break if I remove it. */
+  int max_mask_size; /* The largest possible mask size that will be needed with the given filter and corresponding half_size_filter. The half_size_filter can have a larger requirment in some rare (but not degenerate) cases. */
+  int * * * mask; /* Stores our collection of masks. The first * is for an array of masks, the second for the y axis, and the third for the x axis. */
+  pgm_structure * filter; /* Stores the full-size filter image. This is used to tell what pixels are in the logo or not in the luma plane. */
+  pgm_structure * half_size_filter; /* Stores a 50% width and 50% height filter image. This is used to tell what pixels are in the logo or not in the chroma planes. */
+  /* These 8 variables store the bounding rectangles that the logo resides in. */
+  int bounding_rectangle_posx1;
+  int bounding_rectangle_posy1;
+  int bounding_rectangle_posx2;
+  int bounding_rectangle_posy2;
+  int bounding_rectangle_half_size_posx1;
+  int bounding_rectangle_half_size_posy1;
+  int bounding_rectangle_half_size_posx2;
+  int bounding_rectangle_half_size_posy2;
+} vf_priv_s;
+
+/**
+ * \brief Mallocs memory and checks to make sure it succeeded.
+ *
+ * \param size How many bytes to allocate.
+ *
+ * \return A pointer to the freshly allocated memory block, or NULL on failutre.
+ *
+ * Mallocs memory, and checks to make sure it was successfully allocated. Because
+ * of how MPlayer works, it cannot safely halt execution, but at least the user
+ * will get an error message before the segfault happens.
+ */
+void * safe_malloc(int size)
+{
+  void * answer = malloc(size);
+  if (answer == NULL)
+    mp_msg(MSGT_VFILTER, MSGL_ERR, "Unable to allocate memory in vf_remove_logo.c\n");
+
+  return answer;
+}
+
+/**
+ * \brief Calculates the smallest rectangle that will encompass the logo region.
+ *
+ * \param filter This image contains the logo around which the rectangle will
+ *        will be fitted.
+ *
+ * The bounding rectangle is calculated by testing successive lines (from the four
+ * sides of the rectangle) until no more can be removed without removing logo
+ * pixels. The results are returned by reference to posx1, posy1, posx2, and
+ * posy2.
+ */
+
+void calculate_bounding_rectangle(int * posx1, int * posy1, int * posx2, int * posy2, pgm_structure * filter)
+{
+  int x; /* Temporary variables to run  */
+  int y; /* through each row or column. */
+  int start_x;
+  int start_y; 
+  int end_x = filter->width - 1;
+  int end_y = filter->height - 1;
+  int did_we_find_a_logo_pixel = 0;
+
+  /* Let's find the top bound first. */
+  for (start_x = 0; start_x < filter->width && !did_we_find_a_logo_pixel; start_x++)
+  {
+    for (y = 0; y < filter->height; y++)
+    {
+      did_we_find_a_logo_pixel |= test_filter(filter, start_x, y);
+    }
+  }
+  start_x--;
+
+  /* Now the bottom bound. */
+  did_we_find_a_logo_pixel = 0;
+  for (end_x = filter->width - 1; end_x > start_x && !did_we_find_a_logo_pixel; end_x--)
+  {
+    for (y = 0; y < filter->height; y++)
+    {
+      did_we_find_a_logo_pixel |= test_filter(filter, end_x, y);
+    }
+  }
+  end_x++;
+
+  /* Left bound. */
+  did_we_find_a_logo_pixel = 0;
+  for (start_y = 0; start_y < filter->height && !did_we_find_a_logo_pixel; start_y++)
+  {
+    for (x = 0; x < filter->width; x++)
+    {
+      did_we_find_a_logo_pixel |= test_filter(filter, x, start_y);
+    }
+  }
+  start_y--;
+
+  /* Right bound. */
+  did_we_find_a_logo_pixel = 0;
+  for (end_y = filter->height - 1; end_y > start_y && !did_we_find_a_logo_pixel; end_y--)
+  {
+    for (x = 0; x < filter->width; x++)
+    {
+      did_we_find_a_logo_pixel |= test_filter(filter, x, end_y);
+    }
+  }
+  end_y++;
+
+  *posx1 = start_x;
+  *posy1 = start_y;
+  *posx2 = end_x;
+  *posy2 = end_y;
+
+  return;
+}
+
+/**
+ * \brief Free mask memory.
+ *
+ * \param vf Data structure which stores our persistant data, and is to be freed.
+ *
+ * We call this function when our filter is done. It will free the memory
+ * allocated to the masks and leave the variables in a safe state.
+ */
+void destroy_masks(vf_instance_t * vf)
+{
+  int a, b;
+
+  /* Load values from the vf->priv struct for faster dereferencing. */
+  int * * * mask = ((vf_priv_s *)vf->priv)->mask;
+  int max_mask_size = ((vf_priv_s *)vf->priv)->max_mask_size;
+
+  if (mask == NULL)
+    return; /* Nothing allocated, so return before we segfault. */
+
+  /* Free all allocated memory. */
+  for (a = 0; a <= max_mask_size; a++) /* Loop through each mask. */
+  {
+    for (b = -a; b <= a; b++) /* Loop through each scanline in a mask. */
+    {
+      free(mask[a][b + a]); /* Free a scanline. */
+    }
+    free(mask[a]); /* Free a mask. */
+  }
+  free(mask); /* Free the array of pointers pointing to the masks. */
+
+  /* Set the pointer to NULL, so that any duplicate calls to this function will not cause a crash. */
+  ((vf_priv_s *)vf->priv)->mask = NULL;
+
+  return;
+}
+
+/**
+ * \brief Set up our array of masks.
+ *
+ * \param vf Where our filter stores persistance data, like these masks.
+ *
+ * This creates an array of progressively larger masks and calculates their
+ * values. The values will not change during program execution once this function
+ * is done.
+ */
+void initialize_masks(vf_instance_t * vf)
+{
+  int a, b, c;
+
+  /* Load values from the vf->priv struct for faster dereferencing. */
+  int * * * mask = ((vf_priv_s *)vf->priv)->mask;
+  int max_mask_size = ((vf_priv_s *)vf->priv)->max_mask_size; /* This tells us how many masks we'll need to generate. */
+
+  /* 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 * * *) safe_malloc(sizeof(int * *) * (max_mask_size + 1));
+  for (a = 0; a <= max_mask_size; a++)
+  {
+    mask[a] = (int * *) safe_malloc(sizeof(int *) * ((a * 2) + 1));
+    for (b = -a; b <= a; b++)
+    {
+      mask[a][b + a] = (int *) safe_malloc(sizeof(int) * ((a * 2) + 1));
+      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; 
+      }
+    }
+  }
+
+  /* Store values back to vf->priv so they aren't lost after the function returns. */
+  ((vf_priv_s *)vf->priv)->mask = mask;
+
+  return;
+}
+
+/**
+ * \brief Pre-processes an image to give distance information.
+ *
+ * \param vf Data structure that holds persistant information. All it is used for
+             in this function is to store the calculated max_mask_size variable.
+ * \param mask This image will be converted from a greyscale image into a
+ *             distance image.
+ *
+ * This function takes a greyscale image (pgm_structure * mask) and converts it
+ * in place into a distance image. A distance image is zero for pixels ourside of
+ * the logo and is the manhattan distance (|dx| + |dy|) for pixels inside of the
+ * logo. This will overestimate the distance, but that is safe, and is far easier
+ * to implement than a proper pythagorean distance since I'm using a modified
+ * erosion algorithm to compute the distances.
+ */
+void convert_mask_to_strength_mask(vf_instance_t * vf, pgm_structure * mask)
+{
+  int x, y; /* Used by our for loops to go through every single pixel in the picture one at a time. */
+  int has_anything_changed = 1; /* Used by the main while() loop to know if anything changed on the last erosion. */
+  int current_pass = 0; /* 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 max_mask_size; /* This will record how large a mask the pixel that is the furthest from the edge of the logo
+                           (and thus the neediest) is. */
+  char * current_pixel = mask->pixel; /* This stores the actual pixel data. */
+
+  /* First pass, set all non-zero values to 1. After this loop finishes, the data should be considered numeric
+     data for the filter, not color data. */
+  for (x = 0; x < mask->height * mask->width; x++, current_pixel++)
+    if(*current_pixel) *current_pixel = 1;
+
+  /* Second pass and future passes. 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 (has_anything_changed)
+  {
+    current_pass++;
+    current_pixel = mask->pixel;
+
+    has_anything_changed = 0; /* If this doesn't get set by the end of this pass, then we're done. */
+
+    for (y = 1; y < mask->height - 1; y++)
+    {
+      for (x = 1; x < mask->width - 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. */
+        if (*current_pixel >= current_pass && /* By using >= instead of ==, we allow the algorithm to work in place. */
+            *(current_pixel + 1) >= current_pass &&
+            *(current_pixel - 1) >= current_pass &&
+            *(current_pixel + mask->width) >= current_pass &&
+            *(current_pixel - mask->width) >= current_pass)
+         {
+           (*current_pixel)++; /* Increment the value since it still has not been eroded, as evidenced by the if statement
+                                  that just evaluated to true. */
+           has_anything_changed = 1;
+         }
+        current_pixel++;
+      }
+    }
+  }
+
+  /* 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 < mask->height - 1; y++)
+  {
+   for (x = 1; x < mask->width - 1; x++)
+    {
+      mask->pixel[(y * mask->width) + x] = apply_mask_fudge_factor(mask->pixel[(y * mask->width) + x]);
+    }
+  }
+
+  max_mask_size = current_pass + 1; /* As a side-effect, we now know the maximum mask size, which we'll use to generate our masks. */
+  max_mask_size = apply_mask_fudge_factor(max_mask_size); /* Apply the fudge factor to this number too, since we must
+                                                             ensure that enough masks are generated. */
+  ((vf_priv_s *)vf->priv)->max_mask_size = max_mask_size; /* Commit the newly calculated max_mask_size to the vf->priv struct. */
+
+  return;
+}
+
+/**
+ * \brief Our blurring function.
+ *
+ * \param vf Stores persistant data. In this function we are interested in the
+ *           array of masks.
+ * \param value_out The properly blurred and delogoed pixel is outputted here.
+ * \param logo_mask Tells us which pixels are in the logo and which aren't.
+ * \param image The image that is having its logo removed.
+ * \param x x-coordinate of the pixel to blur.
+ * \param y y-coordinate of the pixel to blur.
+ * \param plane 0 = luma, 1 = blue chroma, 2 = red chroma (YUV).
+ *
+ * This function is the core of the filter. It takes a pixel that is inside the
+ * logo and blurs it. It does so by finding the average of all the pixels within
+ * the mask and outside of the logo.
+ */
+void get_blur(const vf_instance_t * const vf, unsigned int * const value_out, const pgm_structure * const logo_mask,
+              const mp_image_t * const image, const int x, const int y, const int plane)
+{
+  int mask_size; /* Mask size tells how large a circle to use. The radius is about (slightly larger than) mask size. */
+  /* Get values from vf->priv for faster dereferencing. */
+  int * * * mask = ((vf_priv_s *)vf->priv)->mask;
+
+  int start_posx, start_posy, end_posx, end_posy;
+  int i, j;
+  unsigned int accumulator = 0, divisor = 0;
+  const unsigned char * mask_read_position; /* What pixel we are reading out of the circular blur mask. */
+  const unsigned char * logo_mask_read_position; /* What pixel we are reading out of the filter image. */
+
+  /* Prepare our bounding rectangle and clip it if need be. */
+  mask_size = test_filter(logo_mask, x, y);
+  start_posx = max(0, x - mask_size);
+  start_posy = max(0, y - mask_size);
+  end_posx = min(image->width - 1, x + mask_size);
+  end_posy = min(image->height - 1, y + mask_size);
+
+  mask_read_position = image->planes[plane] + (image->stride[plane] * start_posy) + start_posx;
+  logo_mask_read_position = logo_mask->pixel + (start_posy * logo_mask->width) + start_posx;
+
+  for (j = start_posy; j <= end_posy; j++)
+  {
+    for (i = start_posx; i <= end_posx; i++)
+    {
+      if (!(*logo_mask_read_position) && mask[mask_size][i - start_posx][j - start_posy])
+      { /* Check to see if this pixel is in the logo or not. Only use the pixel if it is not. */
+        accumulator += *mask_read_position;
+        divisor++;
+      }
+
+      mask_read_position++;
+      logo_mask_read_position++;
+    }
+
+    mask_read_position += (image->stride[plane] - ((end_posx + 1) - start_posx));
+    logo_mask_read_position += (logo_mask->width - ((end_posx + 1) - start_posx));
+  }
+
+  if (divisor == 0) /* This means that not a single pixel is outside of the logo, so we have no data. */
+  { /* We should put some eye catching value here, to indicate the flaw to the user. */
+    *value_out = 255;
+  }
+  else /* Else we need to normalise the data using the divisor. */
+  {
+    *value_out = (accumulator + (divisor / 2)) / divisor; /* Divide, taking into account average rounding error. */
+  }
+
+  return;
+}
+
+/**
+ * \brief Free a pgm_structure. Undoes load_pgm(...).
+ */
+void destroy_pgm(pgm_structure * to_be_destroyed)
+{
+  if (to_be_destroyed == NULL)
+    return; /* Don't do anything if a NULL pointer was passed it. */
+
+  /* Internally allocated memory. */
+  if (to_be_destroyed->pixel != NULL)
+  {
+    free(to_be_destroyed->pixel);
+    to_be_destroyed->pixel = NULL;
+  }
+
+  /* Free the actual struct instance. This is done here and not by the calling function. */
+  free(to_be_destroyed);
+}
+
+/** \brief Helper function for load_pgm(...) to skip whitespace. */
+void load_pgm_skip(FILE *f) {
+  int c, comment = 0;
+  do {
+    c = fgetc(f);
+    if (c == '#')
+      comment = 1;
+    if (c == '\n')
+      comment = 0;
+  } while (c != EOF && (isspace(c) || comment));
+  ungetc(c, f);
+}
+
+#define REMOVE_LOGO_LOAD_PGM_ERROR_MESSAGE(message) {mp_msg(MSGT_VFILTER, MSGL_ERR, message); return NULL;}
+
+/**
+ * \brief Loads a raw pgm or ppm file into a newly created pgm_structure object.
+ *
+ * \param file_name The name of the file to be loaded. So long as the file is a
+ *                  valid pgm or ppm file, it will load correctly, even if the
+ *                  extension is missing or invalid.
+ *
+ * \return A pointer to the newly created pgm_structure object. Don't forget to
+ *         call destroy_pgm(...) when you're done with this. If an error occurs,
+ *         NULL is returned.
+ *
+ * Can load either raw pgm (P5) or raw ppm (P6) image files as a binary image.
+ * While a pgm file will be loaded normally (greyscale), the only thing that is
+ * guaranteed with ppm is that all zero (R = 0, G = 0, B = 0) pixels will remain
+ * zero, and non-zero pixels will remain non-zero.
+ */
+pgm_structure * load_pgm(const char * file_name)
+{
+  unsigned char flags;
+  int x, y;
+  int maximum_greyscale_value;
+  FILE * input;
+  int pnm_number;
+  pgm_structure * new_pgm = (pgm_structure *) safe_malloc (sizeof(pgm_structure));
+  char * write_position;
+  char * end_position;
+  int image_size; /* width * height */
+
+  if((input = fopen(file_name, "rb")) == NULL) REMOVE_LOGO_LOAD_PGM_ERROR_MESSAGE("[vf]remove-logo: Unable to open file. File not found or insufficient permissions.\n");
+
+  /* Parse the PGM header. */
+  if (fgetc(input) != 'P') REMOVE_LOGO_LOAD_PGM_ERROR_MESSAGE("[vf]remove-logo: File is not a valid PGM or PPM file.\n");
+  pnm_number = fgetc(input) - '0';
+  if (pnm_number != 5 && pnm_number != 6) REMOVE_LOGO_LOAD_PGM_ERROR_MESSAGE("[vf]remove-logo: Invalid PNM file. Only raw PGM (Portable Gray Map) and raw PPM (Portable Pixel Map) subtypes are allowed.\n");
+  load_pgm_skip(input);
+  if (fscanf(input, "%i", &(new_pgm->width)) != 1) REMOVE_LOGO_LOAD_PGM_ERROR_MESSAGE("[vf]remove-logo: Invalid PGM/PPM header.\n");
+  load_pgm_skip(input);
+  if (fscanf(input, "%i", &(new_pgm->height)) != 1) REMOVE_LOGO_LOAD_PGM_ERROR_MESSAGE("[vf]remove-logo: Invalid PGM/PPM header.\n");
+  load_pgm_skip(input);
+  if (fscanf(input, "%i", &maximum_greyscale_value) != 1) REMOVE_LOGO_LOAD_PGM_ERROR_MESSAGE("[vf]remove-logo: Invalid PGM/PPM header.\n");
+  if (maximum_greyscale_value >= 256) REMOVE_LOGO_LOAD_PGM_ERROR_MESSAGE("[vf]remove_logo: Only 1 byte per pixel (pgm) or 1 byte per color value (ppm) are supported.\n");
+  load_pgm_skip(input);
+
+  new_pgm->pixel = (unsigned char *) safe_malloc (sizeof(unsigned char) * new_pgm->width * new_pgm->height);
+
+  /* Load the pixels. */
+  /* Note: I am aware that fgetc(input) isn't the fastest way of doing things, but it is quite compact and the code only runs once when the filter is initialized.*/
+  image_size = new_pgm->width * new_pgm->height;
+  end_position = new_pgm->pixel + image_size;
+  for (write_position = new_pgm->pixel; write_position < end_position; write_position++)
+  {
+    *write_position = fgetc(input);
+    if (pnm_number == 6) /* This tests to see if the file is a PPM file. */
+    { /* If it is, then consider the pixel set if any of the three color channels are set. Since we just care about == 0 or != 0, a bitwise or will do the trick. */
+      *write_position |= fgetc(input);
+      *write_position |= fgetc(input);
+    }
+  }
+
+  return new_pgm;
+}
+
+/**
+ * \brief Generates a scaled down image with half width, height, and intensity.
+ *
+ * \param vf Our struct for persistant data. In this case, it is used to update
+ *           mask_max_size with the larger of the old or new value.
+ * \param input_image The image from which the new half-sized one will be based.
+ *
+ * \return The newly allocated and shrunken image.
+ *
+ * This function not only scales down an image, but halves the value in each pixel
+ * too. The purpose of this is to produce a chroma filter image out of a luma
+ * filter image. The pixel values store the distance to the edge of the logo and
+ * halving the dimensions halves the distance. This function rounds up, because
+ * a downwards rounding error could cause the filter to fail, but an upwards
+ * rounding error will only cause a minor amount of excess blur in the chroma
+ * planes.
+ */
+pgm_structure * generate_half_size_image(vf_instance_t * vf, pgm_structure * input_image)
+{
+  int x, y;
+  pgm_structure * new_pgm = (pgm_structure *) safe_malloc (sizeof(pgm_structure));
+  int has_anything_changed = 1;
+  int current_pass;
+  int max_mask_size;
+  char * current_pixel;
+
+  new_pgm->width = input_image->width / 2;
+  new_pgm->height = input_image->height / 2;
+  new_pgm->pixel = (unsigned char *) safe_malloc (sizeof(unsigned char) * new_pgm->width * new_pgm->height);
+
+  /* Copy over the image data, using the average of 4 pixels for to calculate each downsampled pixel. */
+  for (y = 0; y < new_pgm->height; y++)
+    for (x = 0; x < new_pgm->width; x++)
+    {
+      /* Set the pixel if there exists a non-zero value in the source pixels, else clear it. */
+      new_pgm->pixel[(y * new_pgm->width) + x] = input_image->pixel[((y << 1) * input_image->width) + (x << 1)] ||
+                                                 input_image->pixel[((y << 1) * input_image->width) + (x << 1) + 1] ||
+                                                 input_image->pixel[(((y << 1) + 1) * input_image->width) + (x << 1)] ||
+                                                 input_image->pixel[(((y << 1) + 1) * input_image->width) + (x << 1) + 1];
+      new_pgm->pixel[(y * new_pgm->width) + x] = min(1, new_pgm->pixel[(y * new_pgm->width) + x]);
+    }
+
+  /* Now we need to recalculate the numbers for the smaller size. Just using the old_value / 2 can cause subtle
+     and fairly rare, but very nasty, bugs. */
+
+  current_pixel = new_pgm->pixel;
+  /* First pass, set all non-zero values to 1. */
+  for (x = 0; x < new_pgm->height * new_pgm->width; x++, current_pixel++)
+    if(*current_pixel) *current_pixel = 1;
+
+  /* Second pass and future passes. 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). */
+  current_pass = 0;
+  while (has_anything_changed)
+  {
+    current_pass++;
+
+    has_anything_changed = 0; /* If this doesn't get set by the end of this pass, then we're done. */
+
+    for (y = 1; y < new_pgm->height - 1; y++)
+    {
+      for (x = 1; x < new_pgm->width - 1; x++)
+      {
+        if (new_pgm->pixel[(y * new_pgm->width) + x] >= current_pass && /* By using >= instead of ==, we allow the algorithm to work in place. */
+            new_pgm->pixel[(y * new_pgm->width) + (x + 1)] >= current_pass &&
+            new_pgm->pixel[(y * new_pgm->width) + (x - 1)] >= current_pass &&
+            new_pgm->pixel[((y + 1) * new_pgm->width) + x] >= current_pass &&
+            new_pgm->pixel[((y - 1) * new_pgm->width) + x] >= current_pass)
+         {
+           new_pgm->pixel[(y * new_pgm->width) + x]++; /* Increment the value since it still has not been eroded,
+                                                    as evidenced by the if statement that just evaluated to true. */
+           has_anything_changed = 1;
+         }
+      }
+    }
+  }
+
+  for (y = 1; y < new_pgm->height - 1; y++)
+  {
+   for (x = 1; x < new_pgm->width - 1; x++)
+    {
+      new_pgm->pixel[(y * new_pgm->width) + x] = apply_mask_fudge_factor(new_pgm->pixel[(y * new_pgm->width) + x]);
+    }
+  }
+
+  max_mask_size = current_pass + 1; /* As a side-effect, we now know the maximum mask size, which we'll use to generate our masks. */
+  max_mask_size = apply_mask_fudge_factor(max_mask_size);
+  /* Commit the newly calculated max_mask_size to the vf->priv struct. */
+  ((vf_priv_s *)vf->priv)->max_mask_size = max(max_mask_size, ((vf_priv_s *)vf->priv)->max_mask_size);
+
+  return new_pgm;
+}
+
+/**
+ * \brief Checks if YV12 is supported by the next filter.
+ */
+static unsigned int find_best(struct vf_instance_s* vf){
+  int is_format_okay = vf->next->query_format(vf->next, IMGFMT_YV12);
+  if ((is_format_okay & VFCAP_CSP_SUPPORTED_BY_HW) || (is_format_okay & VFCAP_CSP_SUPPORTED))
+    return IMGFMT_YV12;
+  else
+    return 0;
+}
+
+//===========================================================================//
+
+/**
+ * \brief Configure the filter and call the next filter's config function.
+ */
+static int config(struct vf_instance_s* vf, int width, int height, int d_width, int d_height, unsigned int flags, unsigned int outfmt)
+{
+  if(!(((vf_priv_s *)vf->priv)->fmt=find_best(vf)))
+    return 0;
+  else
+    return vf_next_config(vf,width,height,d_width,d_height,flags,((vf_priv_s *)vf->priv)->fmt);
+}
+
+/**
+ * \brief Removes the logo from a plane (either luma or chroma).
+ *
+ * \param vf Not needed by this function, but needed by the blur function.
+ * \param source The image to have it's logo removed.
+ * \param destination Where the output image will be stored.
+ * \param source_stride How far apart (in memory) two consecutive lines are.
+ * \param destination Same as source_stride, but for the destination image.
+ * \param width Width of the image. This is the same for source and destination.
+ * \param height Height of the image. This is the same for source and destination.
+ * \param is_image_direct If the image is direct, then source and destination are
+ *        the same and we can save a lot of time by not copying pixels that
+ *        haven't changed.
+ * \param filter The image that stores the distance to the edge of the logo for
+ *        each pixel.
+ * \param logo_start_x Smallest x-coordinate that contains at least 1 logo pixel.
+ * \param logo_start_y Smallest y-coordinate that contains at least 1 logo pixel.
+ * \param logo_end_x Largest x-coordinate that contains at least 1 logo pixel.
+ * \param logo_end_y Largest y-coordinate that contains at least 1 logo pixel.
+ *
+ * This function processes an entire plane. Pixels outside of the logo are copied
+ * to the output without change, and pixels inside the logo have the de-blurring
+ * function applied.
+ */
+static void convert_yv12(const vf_instance_t * const vf, const char * const source, const int source_stride,
+                         const mp_image_t * const source_image, const int width, const int height,
+                         char * const destination, const int destination_stride, int is_image_direct, pgm_structure * filter,
+                         const int plane, const int logo_start_x, const int logo_start_y, const int logo_end_x, const int logo_end_y)
+{
+  int y;
+  int x;
+
+  /* These pointers point to where we are getting our pixel data (inside mpi) and where we are storing it (inside dmpi). */
+  const unsigned char * source_line;
+  unsigned char * destination_line;
+
+  if (!is_image_direct)
+    memcpy_pic(destination, source, width, height, destination_stride, source_stride);
+
+  for (y = logo_start_y; y <= logo_end_y; y++)
+  {
+    source_line = (const unsigned char *) source + (source_stride * y);
+    destination_line = (unsigned char *) destination + (destination_stride * y);
+
+    for (x = logo_start_x; x <= logo_end_x; x++)
+    {
+      unsigned int output;
+
+      if (filter->pixel[(y * filter->width) + x]) /* Only process if we are in the logo. */
+      {
+        get_blur(vf, &output, filter, source_image, x, y, plane);
+        destination_line[x] = output;
+      }
+      else /* Else just copy the data. */
+        if (!is_image_direct)
+          destination_line[x] = source_line[x];
+    }
+  }
+}
+
+/**
+ * \brief Process a frame.
+ *
+ * \param mpi The image sent to use by the previous filter.
+ * \param dmpi Where we will store the processed output image.
+ * \param vf This is how the filter gets access to it's persistant data.
+ *
+ * \return The return code of the next filter, or 0 on failure/error.
+ *
+ * This function processes an entire frame. The frame is sent by the previous
+ * filter, has the logo removed by the filter, and is then sent to the next
+ * filter.
+ */
+static int put_image(struct vf_instance_s* vf, mp_image_t *mpi){
+    mp_image_t *dmpi;
+    
+    dmpi=vf_get_image(vf->next,((vf_priv_s *)vf->priv)->fmt,
+	MP_IMGTYPE_TEMP, MP_IMGFLAG_ACCEPT_STRIDE,
+	mpi->w, mpi->h);
+
+    /* Check to make sure that the filter image and the video stream are the same size. */
+    if ((((vf_priv_s *)vf->priv)->filter->width != mpi->w) || (((vf_priv_s *)vf->priv)->filter->height != mpi->h))
+    {
+      mp_msg(MSGT_VFILTER,MSGL_ERR, "Filter image and video stream are not of the same size. (Filter: %d x %d, Stream: %d x %d)\n",
+             ((vf_priv_s *)vf->priv)->filter->width, ((vf_priv_s *)vf->priv)->filter->height, mpi->w, mpi->h);
+      return 0;
+    }
+
+    switch(dmpi->imgfmt){
+    case IMGFMT_YV12:
+          convert_yv12(vf, mpi->planes[0],  mpi->stride[0], mpi, mpi->w, mpi->h,
+                          dmpi->planes[0], dmpi->stride[0],
+                          mpi->flags & MP_IMGFLAG_DIRECT, ((vf_priv_s *)vf->priv)->filter, 0,
+                          ((vf_priv_s *)vf->priv)->bounding_rectangle_posx1, ((vf_priv_s *)vf->priv)->bounding_rectangle_posy1,
+                          ((vf_priv_s *)vf->priv)->bounding_rectangle_posx2, ((vf_priv_s *)vf->priv)->bounding_rectangle_posy2);
+