avfilter/vf_threshold: fix handling of zero threshold

libavfilter/vf_threshold_init.h

@@ -38,7 +38,7 @@ static void threshold8(const uint8_t *in, const uint8_t *threshold,
 {
     for (int y = 0; y < h; y++) {
         for (int x = 0; x < w; x++)
-            out[x] = in[x] < threshold[x] ? min[x] : max[x];
+            out[x] = in[x] <= threshold[x] ? min[x] : max[x];
 
         in        += ilinesize;
         threshold += tlinesize;
@@ -64,7 +64,7 @@ static void threshold16(const uint8_t *iin, const uint8_t *tthreshold,
 
     for (int y = 0; y < h; y++) {
         for (int x = 0; x < w; x++)
-            out[x] = in[x] < threshold[x] ? min[x] : max[x];
+            out[x] = in[x] <= threshold[x] ? min[x] : max[x];
 
         in        += ilinesize / 2;
         threshold += tlinesize / 2;

libavfilter/x86/vf_threshold.asm

@@ -22,15 +22,10 @@
 
 %include "libavutil/x86/x86util.asm"
 
-SECTION_RODATA
-
-pb_128: times 16 db 128
-pb_128_0 : times 8 db 0, 128
-
 SECTION .text
 
-;%1 depth (8 or 16) ; %2 b or w ; %3 constant
-%macro THRESHOLD 3
+;%1 depth (8 or 16) ; %2 b or w
+%macro THRESHOLD 2
 %if ARCH_X86_64
 cglobal threshold%1, 10, 13, 5, in, threshold, min, max, out, ilinesize, tlinesize, flinesize, slinesize, olinesize, w, h, x
     mov             wd, dword wm
@@ -45,7 +40,6 @@ cglobal threshold%1, 5, 7, 5, in, threshold, min, max, out, w, x
 %define     olinesizeq  r9mp
 %define             hd  r11mp
 %endif
-    VBROADCASTI128  m4, [%3]
 %if %1 == 16
     add             wq, wq ; w *= 2 (16 bits instead of 8)
 %endif
@@ -63,9 +57,8 @@ cglobal threshold%1, 5, 7, 5, in, threshold, min, max, out, w, x
         movu            m0, [thresholdq + xq]
         movu            m2, [minq + xq]
         movu            m3, [maxq + xq]
-        pxor            m0, m4
-        pxor            m1, m4
-        pcmpgt%2        m0, m1
+        pminu%2         m0, m1
+        pcmpeq%2        m0, m1
         PBLENDVB        m3, m2, m0
         movu   [outq + xq], m3
         add             xq, mmsize
@@ -82,11 +75,11 @@ RET
 %endmacro
 
 INIT_XMM sse4
-THRESHOLD 8, b, pb_128
-THRESHOLD 16, w, pb_128_0
+THRESHOLD 8, b
+THRESHOLD 16, w
 
 %if HAVE_AVX2_EXTERNAL
 INIT_YMM avx2
-THRESHOLD 8, b, pb_128
-THRESHOLD 16, w, pb_128_0
+THRESHOLD 8, b
+THRESHOLD 16, w
 %endif