uref_filter_kernel: optimconvol

1 files changed, 19 insertions, 9 deletions

diff --git a/include/upipe-filters/uref_filter_kernel.h b/include/upipe-filters/uref_filter_kernel.h
index 5556470..ffeff5d 100644
--- a/include/upipe-filters/uref_filter_kernel.h
+++ b/include/upipe-filters/uref_filter_kernel.h
@@ -28,11 +28,11 @@ static inline void uref_filter_kernel_plane(const uint8_t *src, uint8_t *dst,
                               int sstride, int dstride, int hsize, int vsize,
                               const int8_t *kern, int khsize, int kvsize)
 {
-    int i, j, m, n;
+    int i, j, m, n, kh, kv, maxh, maxv;
     int norm;
-    register int sum;
-    register const uint8_t *line;
-    register const int8_t *kline;
+    int sum;
+    const uint8_t *line, *zone;
+    const int8_t *kline;
 
     norm = 0;
     for (n=0; n < kvsize*khsize; n++) {
@@ -41,19 +41,28 @@ static inline void uref_filter_kernel_plane(const uint8_t *src, uint8_t *dst,
 
     assert(khsize < hsize && kvsize < vsize);
 
+    /* ignore borders */
+    kh = khsize/2;
+    kv = kvsize/2;
+    maxh = hsize - kh;
+    maxv = vsize - kv;
+
+    /* align source with kernel center */
+    zone = src - sstride * kv - kh;
+
 #if 1
-    for (i=kvsize/2; i < (vsize - kvsize/2); i++) {
-        for (j=khsize/2; j < (hsize - khsize/2); j++) {
+    for (i=kv; i < maxv; i++) {
+        for (j=kh; j < maxh; j++) {
             sum = 0;
-            line = src + sstride * (i - kvsize / 2);
+            line = zone + j;
 
             kline = kern;
             for (m = 0; m < kvsize; m++) {
                 for (n = 0; n < khsize; n++) {
-                    sum += kline[n] * line[j+n-khsize/2];
+                    sum += *kline++ * *line++;
                 }
                 line += sstride;
-                kline += khsize;
+                line -= khsize;
             }
 
             if (norm) {
@@ -64,6 +73,7 @@ static inline void uref_filter_kernel_plane(const uint8_t *src, uint8_t *dst,
         }
 
         dst += dstride;
+        zone += sstride;
     }
 #else
     for (i=0; i < vsize; i++) {