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[FFmpeg-devel,1/2] lafi/vf_edgedetect: Move some functions to lavu/imgutils

Message ID 0c6142b3-ab81-120a-f38a-a88c3dc66ac0@mail.de
State New
Headers show
Series [FFmpeg-devel,1/2] lafi/vf_edgedetect: Move some functions to lavu/imgutils
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Commit Message

Thilo Borgmann Nov. 16, 2021, 12:55 p.m. UTC
Hi,

shared code with vf_blurriness.c in patch 2/2.
RFC: is there a better place to put these?

-Thilo
From b4e3701b2ed034b8d60aeff5d5ed75e4d4332a9f Mon Sep 17 00:00:00 2001
From: Thilo Borgmann <thilo.borgmann@mail.de>
Date: Tue, 16 Nov 2021 13:35:02 +0100
Subject: [PATCH 1/2] lafi/vf_edgedetect: Move some functions to lavu/imgutils

---
 libavfilter/vf_edgedetect.c | 127 +-----------------------------------
 libavutil/imgutils.c        | 120 ++++++++++++++++++++++++++++++++++
 libavutil/imgutils.h        |  63 ++++++++++++++++++
 3 files changed, 186 insertions(+), 124 deletions(-)

Comments

Andreas Rheinhardt Nov. 18, 2021, 3:37 a.m. UTC | #1
Thilo Borgmann:
> Hi,
> 
> shared code with vf_blurriness.c in patch 2/2.
> RFC: is there a better place to put these?
> 

If you only need this in libavfilter, then why do you put it into
libavutil, thereby making it public and adding all sorts of ABI
complications?

- Andreas
Paul B Mahol Nov. 18, 2021, 10:25 a.m. UTC | #2
On Thu, Nov 18, 2021 at 4:38 AM Andreas Rheinhardt <
andreas.rheinhardt@outlook.com> wrote:

> Thilo Borgmann:
> > Hi,
> >
> > shared code with vf_blurriness.c in patch 2/2.
> > RFC: is there a better place to put these?
> >
>
> If you only need this in libavfilter, then why do you put it into
> libavutil, thereby making it public and adding all sorts of ABI
> complications?
>

Yea, sharing it with avutil is not going to work.


>
> - Andreas
> _______________________________________________
> ffmpeg-devel mailing list
> ffmpeg-devel@ffmpeg.org
> https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
>
> To unsubscribe, visit link above, or email
> ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".
>
diff mbox series

Patch

diff --git a/libavfilter/vf_edgedetect.c b/libavfilter/vf_edgedetect.c
index 3eea34e325..9750ba5f98 100644
--- a/libavfilter/vf_edgedetect.c
+++ b/libavfilter/vf_edgedetect.c
@@ -188,127 +188,6 @@  static void gaussian_blur(AVFilterContext *ctx, int w, int h,
         memcpy(dst, src, w);
 }
 
-enum {
-    DIRECTION_45UP,
-    DIRECTION_45DOWN,
-    DIRECTION_HORIZONTAL,
-    DIRECTION_VERTICAL,
-};
-
-static int get_rounded_direction(int gx, int gy)
-{
-    /* reference angles:
-     *   tan( pi/8) = sqrt(2)-1
-     *   tan(3pi/8) = sqrt(2)+1
-     * Gy/Gx is the tangent of the angle (theta), so Gy/Gx is compared against
-     * <ref-angle>, or more simply Gy against <ref-angle>*Gx
-     *
-     * Gx and Gy bounds = [-1020;1020], using 16-bit arithmetic:
-     *   round((sqrt(2)-1) * (1<<16)) =  27146
-     *   round((sqrt(2)+1) * (1<<16)) = 158218
-     */
-    if (gx) {
-        int tanpi8gx, tan3pi8gx;
-
-        if (gx < 0)
-            gx = -gx, gy = -gy;
-        gy *= (1 << 16);
-        tanpi8gx  =  27146 * gx;
-        tan3pi8gx = 158218 * gx;
-        if (gy > -tan3pi8gx && gy < -tanpi8gx)  return DIRECTION_45UP;
-        if (gy > -tanpi8gx  && gy <  tanpi8gx)  return DIRECTION_HORIZONTAL;
-        if (gy >  tanpi8gx  && gy <  tan3pi8gx) return DIRECTION_45DOWN;
-    }
-    return DIRECTION_VERTICAL;
-}
-
-static void sobel(int w, int h,
-                       uint16_t *dst, int dst_linesize,
-                         int8_t *dir, int dir_linesize,
-                  const uint8_t *src, int src_linesize)
-{
-    int i, j;
-
-    for (j = 1; j < h - 1; j++) {
-        dst += dst_linesize;
-        dir += dir_linesize;
-        src += src_linesize;
-        for (i = 1; i < w - 1; i++) {
-            const int gx =
-                -1*src[-src_linesize + i-1] + 1*src[-src_linesize + i+1]
-                -2*src[                i-1] + 2*src[                i+1]
-                -1*src[ src_linesize + i-1] + 1*src[ src_linesize + i+1];
-            const int gy =
-                -1*src[-src_linesize + i-1] + 1*src[ src_linesize + i-1]
-                -2*src[-src_linesize + i  ] + 2*src[ src_linesize + i  ]
-                -1*src[-src_linesize + i+1] + 1*src[ src_linesize + i+1];
-
-            dst[i] = FFABS(gx) + FFABS(gy);
-            dir[i] = get_rounded_direction(gx, gy);
-        }
-    }
-}
-
-static void non_maximum_suppression(int w, int h,
-                                          uint8_t  *dst, int dst_linesize,
-                                    const  int8_t  *dir, int dir_linesize,
-                                    const uint16_t *src, int src_linesize)
-{
-    int i, j;
-
-#define COPY_MAXIMA(ay, ax, by, bx) do {                \
-    if (src[i] > src[(ay)*src_linesize + i+(ax)] &&     \
-        src[i] > src[(by)*src_linesize + i+(bx)])       \
-        dst[i] = av_clip_uint8(src[i]);                 \
-} while (0)
-
-    for (j = 1; j < h - 1; j++) {
-        dst += dst_linesize;
-        dir += dir_linesize;
-        src += src_linesize;
-        for (i = 1; i < w - 1; i++) {
-            switch (dir[i]) {
-            case DIRECTION_45UP:        COPY_MAXIMA( 1, -1, -1,  1); break;
-            case DIRECTION_45DOWN:      COPY_MAXIMA(-1, -1,  1,  1); break;
-            case DIRECTION_HORIZONTAL:  COPY_MAXIMA( 0, -1,  0,  1); break;
-            case DIRECTION_VERTICAL:    COPY_MAXIMA(-1,  0,  1,  0); break;
-            }
-        }
-    }
-}
-
-static void double_threshold(int low, int high, int w, int h,
-                                   uint8_t *dst, int dst_linesize,
-                             const uint8_t *src, int src_linesize)
-{
-    int i, j;
-
-    for (j = 0; j < h; j++) {
-        for (i = 0; i < w; i++) {
-            if (src[i] > high) {
-                dst[i] = src[i];
-                continue;
-            }
-
-            if (!(!i || i == w - 1 || !j || j == h - 1) &&
-                src[i] > low &&
-                (src[-src_linesize + i-1] > high ||
-                 src[-src_linesize + i  ] > high ||
-                 src[-src_linesize + i+1] > high ||
-                 src[                i-1] > high ||
-                 src[                i+1] > high ||
-                 src[ src_linesize + i-1] > high ||
-                 src[ src_linesize + i  ] > high ||
-                 src[ src_linesize + i+1] > high))
-                dst[i] = src[i];
-            else
-                dst[i] = 0;
-        }
-        dst += dst_linesize;
-        src += src_linesize;
-    }
-}
-
 static void color_mix(int w, int h,
                             uint8_t *dst, int dst_linesize,
                       const uint8_t *src, int src_linesize)
@@ -365,7 +244,7 @@  static int filter_frame(AVFilterLink *inlink, AVFrame *in)
                       in->data[p], in->linesize[p]);
 
         /* compute the 16-bits gradients and directions for the next step */
-        sobel(width, height,
+        av_image_sobel(width, height,
               gradients, width,
               directions,width,
               tmpbuf,    width);
@@ -373,13 +252,13 @@  static int filter_frame(AVFilterLink *inlink, AVFrame *in)
         /* non_maximum_suppression() will actually keep & clip what's necessary and
          * ignore the rest, so we need a clean output buffer */
         memset(tmpbuf, 0, width * height);
-        non_maximum_suppression(width, height,
+        av_image_non_maximum_suppression(width, height,
                                 tmpbuf,    width,
                                 directions,width,
                                 gradients, width);
 
         /* keep high values, or low values surrounded by high values */
-        double_threshold(edgedetect->low_u8, edgedetect->high_u8,
+        av_image_double_threshold(edgedetect->low_u8, edgedetect->high_u8,
                          width, height,
                          out->data[p], out->linesize[p],
                          tmpbuf,       width);
diff --git a/libavutil/imgutils.c b/libavutil/imgutils.c
index 9ab5757cf6..fdb1331077 100644
--- a/libavutil/imgutils.c
+++ b/libavutil/imgutils.c
@@ -690,3 +690,123 @@  int av_image_fill_black(uint8_t *dst_data[4], const ptrdiff_t dst_linesize[4],
 
     return 0;
 }
+
+// Internal helper for av_image_sobel()
+static int get_rounded_direction(int gx, int gy)
+{
+    /* reference angles:
+     *   tan( pi/8) = sqrt(2)-1
+     *   tan(3pi/8) = sqrt(2)+1
+     * Gy/Gx is the tangent of the angle (theta), so Gy/Gx is compared against
+     * <ref-angle>, or more simply Gy against <ref-angle>*Gx
+     *
+     * Gx and Gy bounds = [-1020;1020], using 16-bit arithmetic:
+     *   round((sqrt(2)-1) * (1<<16)) =  27146
+     *   round((sqrt(2)+1) * (1<<16)) = 158218
+     */
+    if (gx) {
+        int tanpi8gx, tan3pi8gx;
+
+        if (gx < 0)
+            gx = -gx, gy = -gy;
+        gy *= (1 << 16);
+        tanpi8gx  =  27146 * gx;
+        tan3pi8gx = 158218 * gx;
+        if (gy > -tan3pi8gx && gy < -tanpi8gx)  return DIRECTION_45UP;
+        if (gy > -tanpi8gx  && gy <  tanpi8gx)  return DIRECTION_HORIZONTAL;
+        if (gy >  tanpi8gx  && gy <  tan3pi8gx) return DIRECTION_45DOWN;
+    }
+    return DIRECTION_VERTICAL;
+}
+
+// Simple sobel operator to get rounded gradients
+void av_image_sobel(int w, int h,
+                    uint16_t *dst, int dst_linesize,
+                    int8_t *dir, int dir_linesize,
+                    const uint8_t *src, int src_linesize)
+{
+    int i, j;
+
+    for (j = 1; j < h - 1; j++) {
+        dst += dst_linesize;
+        dir += dir_linesize;
+        src += src_linesize;
+        for (i = 1; i < w - 1; i++) {
+            const int gx =
+                -1*src[-src_linesize + i-1] + 1*src[-src_linesize + i+1]
+                -2*src[                i-1] + 2*src[                i+1]
+                -1*src[ src_linesize + i-1] + 1*src[ src_linesize + i+1];
+            const int gy =
+                -1*src[-src_linesize + i-1] + 1*src[ src_linesize + i-1]
+                -2*src[-src_linesize + i  ] + 2*src[ src_linesize + i  ]
+                -1*src[-src_linesize + i+1] + 1*src[ src_linesize + i+1];
+
+            dst[i] = FFABS(gx) + FFABS(gy);
+            dir[i] = get_rounded_direction(gx, gy);
+        }
+    }
+}
+
+// Filters rounded gradients to drop all non-maxima
+// Expects gradients generated by av_image_sobel()
+// Expects zero's destination buffer
+void av_image_non_maximum_suppression(int w, int h,
+                                      uint8_t *dst, int dst_linesize,
+                                      const int8_t *dir, int dir_linesize,
+                                      const uint16_t *src, int src_linesize)
+{
+    int i, j;
+
+#define COPY_MAXIMA(ay, ax, by, bx) do {                \
+    if (src[i] > src[(ay)*src_linesize + i+(ax)] &&     \
+        src[i] > src[(by)*src_linesize + i+(bx)])       \
+        dst[i] = av_clip_uint8(src[i]);                 \
+} while (0)
+
+    for (j = 1; j < h - 1; j++) {
+        dst += dst_linesize;
+        dir += dir_linesize;
+        src += src_linesize;
+        for (i = 1; i < w - 1; i++) {
+            switch (dir[i]) {
+            case DIRECTION_45UP:        COPY_MAXIMA( 1, -1, -1,  1); break;
+            case DIRECTION_45DOWN:      COPY_MAXIMA(-1, -1,  1,  1); break;
+            case DIRECTION_HORIZONTAL:  COPY_MAXIMA( 0, -1,  0,  1); break;
+            case DIRECTION_VERTICAL:    COPY_MAXIMA(-1,  0,  1,  0); break;
+            }
+        }
+    }
+}
+
+// Filter to keep all pixels > high, and keep all pixels > low where all surrounding pixels > high
+void av_image_double_threshold(int low, int high, int w, int h,
+                               uint8_t *dst, int dst_linesize,
+                               const uint8_t *src, int src_linesize)
+{
+    int i, j;
+
+    for (j = 0; j < h; j++) {
+        for (i = 0; i < w; i++) {
+            if (src[i] > high) {
+                dst[i] = src[i];
+                continue;
+            }
+
+            if (!(!i || i == w - 1 || !j || j == h - 1) &&
+                src[i] > low &&
+                (src[-src_linesize + i-1] > high ||
+                 src[-src_linesize + i  ] > high ||
+                 src[-src_linesize + i+1] > high ||
+                 src[                i-1] > high ||
+                 src[                i+1] > high ||
+                 src[ src_linesize + i-1] > high ||
+                 src[ src_linesize + i  ] > high ||
+                 src[ src_linesize + i+1] > high))
+                dst[i] = src[i];
+            else
+                dst[i] = 0;
+        }
+        dst += dst_linesize;
+        src += src_linesize;
+    }
+}
diff --git a/libavutil/imgutils.h b/libavutil/imgutils.h
index cb2d74728e..a0514a67f0 100644
--- a/libavutil/imgutils.h
+++ b/libavutil/imgutils.h
@@ -301,6 +301,69 @@  int av_image_fill_black(uint8_t *dst_data[4], const ptrdiff_t dst_linesize[4],
                         enum AVPixelFormat pix_fmt, enum AVColorRange range,
                         int width, int height);
 
+/**
+ * @brief Rounded directions used in av_image_sobel()
+ */
+enum AVRoundedDirection {
+    DIRECTION_45UP,
+    DIRECTION_45DOWN,
+    DIRECTION_HORIZONTAL,
+    DIRECTION_VERTICAL,
+};
+
+/**
+ * Simple sobel operator to get rounded gradients
+ *
+ * @param w             the width of the image in pixels
+ * @param h             the height of the image in pixels
+ * @param dst           data pointers to magnitude image
+ * @param dst_linesize  linesizes for the magnitude image
+ * @param dir           data pointers to direction image
+ * @param dir_linesize  linesizes for the direction image
+ * @param src           data pointers to source image
+ * @param src_linesize  linesizes for the source image
+ */
+void av_image_sobel(int w, int h,
+                    uint16_t *dst, int dst_linesize,
+                    int8_t *dir, int dir_linesize,
+                    const uint8_t *src, int src_linesize);
+
+/**
+ * Filters rounded gradients to drop all non-maxima pixels in the magnitude image
+ * Expects gradients generated by av_image_sobel()
+ * Expects zero's in the destination buffer dst
+ *
+ * @param w             the width of the image in pixels
+ * @param h             the height of the image in pixels
+ * @param dst           data pointers to magnitude image
+ * @param dst_linesize  linesizes for the magnitude image
+ * @param dir           data pointers to direction image
+ * @param dir_linesize  linesizes for the direction image
+ * @param src           data pointers to source image
+ * @param src_linesize  linesizes for the source image
+ */
+void av_image_non_maximum_suppression(int w, int h,
+                                      uint8_t *dst, int dst_linesize,
+                                      const int8_t *dir, int dir_linesize,
+                                      const uint16_t *src, int src_linesize);
+
+/**
+ * Filters all pixels in src to keep all pixels > high,
+ * and keep all pixels > low where all surrounding pixels > high
+ *
+ * @param low           the low threshold value
+ * @param high          the hegh threshold value
+ * @param w             the width of the image in pixels
+ * @param h             the height of the image in pixels
+ * @param dst           data pointers to destination image
+ * @param dst_linesize  linesizes for the destination image
+ * @param src           data pointers to source image
+ * @param src_linesize  linesizes for the source image
+ */
+void av_image_double_threshold(int low, int high, int w, int h,
+                               uint8_t *dst, int dst_linesize,
+                               const uint8_t *src, int src_linesize);
+
 /**
  * @}
  */