fade: fix slice sizes

This more evenly distributes the load between threads

This also fixes the chroma filtering where the filter was applied twice
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavfilter/vf_fade.c

@@ -163,9 +163,8 @@ static int filter_slice_luma(AVFilterContext *ctx, void *arg, int jobnr,
 {
     FadeContext *s = ctx->priv;
     AVFrame *frame = arg;
-    int slice_h     = frame->height / nb_jobs;
-    int slice_start = jobnr * slice_h;
-    int slice_end   = (jobnr == nb_jobs - 1) ? frame->height : (jobnr + 1) * slice_h;
+    int slice_start = (frame->height *  jobnr   ) / nb_jobs;
+    int slice_end   = (frame->height * (jobnr+1)) / nb_jobs;
     int i, j;
 
     for (i = slice_start; i < slice_end; i++) {
@@ -187,15 +186,15 @@ static int filter_slice_chroma(AVFilterContext *ctx, void *arg, int jobnr,
 {
     FadeContext *s = ctx->priv;
     AVFrame *frame = arg;
-    int slice_h     = FFALIGN(frame->height / nb_jobs, 1 << s->vsub);
-    int slice_start = jobnr * slice_h;
-    int slice_end   = (jobnr == nb_jobs - 1) ? frame->height : (jobnr + 1) * slice_h;
     int i, j, plane;
     const int width = FF_CEIL_RSHIFT(frame->width, s->hsub);
+    const int height= FF_CEIL_RSHIFT(frame->height, s->vsub);
+    int slice_start = (height *  jobnr   ) / nb_jobs;
+    int slice_end   = (height * (jobnr+1)) / nb_jobs;
 
     for (plane = 1; plane < 3; plane++) {
         for (i = slice_start; i < slice_end; i++) {
-            uint8_t *p = frame->data[plane] + (i >> s->vsub) * frame->linesize[plane];
+            uint8_t *p = frame->data[plane] + i * frame->linesize[plane];
             for (j = 0; j < width; j++) {
                 /* 8421367 = ((128 << 1) + 1) << 15. It is an integer
                  * representation of 128.5. The .5 is for rounding

tests/ref/fate/filter-fade

@@ -5,20 +5,20 @@
 0,          3,          3,        1,   152064, 0xb4e6c735
 0,          4,          4,        1,   152064, 0xb4e6c735
 0,          5,          5,        1,   152064, 0xb4e6c735
-0,          6,          6,        1,   152064, 0x54bae320
-0,          7,          7,        1,   152064, 0x53b60b7e
-0,          8,          8,        1,   152064, 0x8bed0304
-0,          9,          9,        1,   152064, 0x509c4b78
-0,         10,         10,        1,   152064, 0x4cf869a4
-0,         11,         11,        1,   152064, 0x958b7c66
-0,         12,         12,        1,   152064, 0x45841fbf
-0,         13,         13,        1,   152064, 0xcfee57ea
-0,         14,         14,        1,   152064, 0x979ff709
-0,         15,         15,        1,   152064, 0xf7ffd5e2
-0,         16,         16,        1,   152064, 0xc42f4370
-0,         17,         17,        1,   152064, 0x71ae098f
-0,         18,         18,        1,   152064, 0x64146a42
-0,         19,         19,        1,   152064, 0xdb3068fd
+0,          6,          6,        1,   152064, 0x1f3b0657
+0,          7,          7,        1,   152064, 0x6e7547e6
+0,          8,          8,        1,   152064, 0x1197524c
+0,          9,          9,        1,   152064, 0xb4cdb293
+0,         10,         10,        1,   152064, 0xdd7cf1b8
+0,         11,         11,        1,   152064, 0x360b1005
+0,         12,         12,        1,   152064, 0x11a49918
+0,         13,         13,        1,   152064, 0xa10dd4f9
+0,         14,         14,        1,   152064, 0x78da71d7
+0,         15,         15,        1,   152064, 0x105e4cc0
+0,         16,         16,        1,   152064, 0x54bfa1c5
+0,         17,         17,        1,   152064, 0xd666559e
+0,         18,         18,        1,   152064, 0xd93faa1c
+0,         19,         19,        1,   152064, 0xb1af85ed
 0,         20,         20,        1,   152064, 0xfc7bf570
 0,         21,         21,        1,   152064, 0x9dc72412
 0,         22,         22,        1,   152064, 0x445d1d59
@@ -30,20 +30,20 @@
 0,         28,         28,        1,   152064, 0x76d2a455
 0,         29,         29,        1,   152064, 0x6dc3650e
 0,         30,         30,        1,   152064, 0x0f9d6aca
-0,         31,         31,        1,   152064, 0x11446a9b
-0,         32,         32,        1,   152064, 0x00be684c
-0,         33,         33,        1,   152064, 0xe5f9ee52
-0,         34,         34,        1,   152064, 0x21ecafb8
-0,         35,         35,        1,   152064, 0xd42c962c
-0,         36,         36,        1,   152064, 0xe00a270d
-0,         37,         37,        1,   152064, 0xc1b53878
-0,         38,         38,        1,   152064, 0xfc4e28dd
-0,         39,         39,        1,   152064, 0x9c574e39
-0,         40,         40,        1,   152064, 0xdd25cf9d
-0,         41,         41,        1,   152064, 0x32959e70
-0,         42,         42,        1,   152064, 0xac6498d5
-0,         43,         43,        1,   152064, 0xcd595d21
-0,         44,         44,        1,   152064, 0x2953ff74
+0,         31,         31,        1,   152064, 0xddae8141
+0,         32,         32,        1,   152064, 0x67cb8f24
+0,         33,         33,        1,   152064, 0xc7a72348
+0,         34,         34,        1,   152064, 0x0d7a1144
+0,         35,         35,        1,   152064, 0x39adfb3d
+0,         36,         36,        1,   152064, 0x0ecc70d5
+0,         37,         37,        1,   152064, 0xf3a6805e
+0,         38,         38,        1,   152064, 0xc3bd71ad
+0,         39,         39,        1,   152064, 0xa9be9730
+0,         40,         40,        1,   152064, 0xab9af790
+0,         41,         41,        1,   152064, 0x4c3ccd25
+0,         42,         42,        1,   152064, 0xbc83c58a
+0,         43,         43,        1,   152064, 0x94877df4
+0,         44,         44,        1,   152064, 0xa2360ea6
 0,         45,         45,        1,   152064, 0xb4e6c735
 0,         46,         46,        1,   152064, 0xb4e6c735
 0,         47,         47,        1,   152064, 0xb4e6c735