[FFmpeg-devel] [PATCH 3/4] libswscale: Enable hscale_avx2 for input sizes which ar emultiples of 4.

[Alan Kelly]

ff_shuffle_filter_coefficients shuffles the tail as required.
---
 libswscale/utils.c       | 17 +++++++++++++++--
 libswscale/x86/swscale.c |  4 ++--
 2 files changed, 17 insertions(+), 4 deletions(-)

diff --git a/libswscale/utils.c b/libswscale/utils.c
index 52f07e1661..7e1e9c3834 100644
--- a/libswscale/utils.c
+++ b/libswscale/utils.c
@@ -285,7 +285,7 @@ int ff_shuffle_filter_coefficients(SwsContext *c, int *filterPos,
 #if ARCH_X86_64
     int i = 0, j = 0, k = 0;
     int cpu_flags = av_get_cpu_flags();
-    if (!filter || dstW % 16 != 0) return 0;
+    if (!filter || (dstW % 4 != 0)) return 0;
     if (EXTERNAL_AVX2_FAST(cpu_flags) && !(cpu_flags & AV_CPU_FLAG_SLOW_GATHER)) {
         if ((c->srcBpc == 8) && (c->dstBpc <= 14)) {
            int16_t *filterCopy = NULL;
@@ -296,9 +296,11 @@ int ff_shuffle_filter_coefficients(SwsContext *c, int *filterPos,
            }
            // Do not swap filterPos for pixels which won't be processed by
            // the main loop.
-           for (i = 0; i + 8 <= dstW; i += 8) {
+           for (i = 0; i + 16 <= dstW; i += 16) {
                FFSWAP(int, filterPos[i + 2], filterPos[i + 4]);
                FFSWAP(int, filterPos[i + 3], filterPos[i + 5]);
+               FFSWAP(int, filterPos[i + 10], filterPos[i + 12]);
+               FFSWAP(int, filterPos[i + 11], filterPos[i + 13]);
            }
            if (filterSize > 4) {
                // 16 pixels are processed at a time.
@@ -312,6 +314,17 @@ int ff_shuffle_filter_coefficients(SwsContext *c, int *filterPos,
                        }
                    }
                }
+               // 4 pixels are processed at a time in the tail.
+               for (; i + 4 <= dstW; i += 4) {
+                   // 4 filter coeffs are processed at a time.
+                   for (k = 0; k + 4 <= filterSize; k += 4) {
+                       for (j = 0; j < 4; ++j) {
+                           int from = (i + j) * filterSize + k;
+                           int to = i * filterSize + j * 4 + k * 4;
+                           memcpy(&filter[to], &filterCopy[from], 4 * sizeof(int16_t));
+                       }
+                   }
+               }
            }
            if (filterCopy)
                av_free(filterCopy);
diff --git a/libswscale/x86/swscale.c b/libswscale/x86/swscale.c
index fdc93866a6..1d8f19aa5a 100644
--- a/libswscale/x86/swscale.c
+++ b/libswscale/x86/swscale.c
@@ -580,9 +580,9 @@ switch(c->dstBpc){ \
 
     if (EXTERNAL_AVX2_FAST(cpu_flags) && !(cpu_flags & AV_CPU_FLAG_SLOW_GATHER)) {
         if ((c->srcBpc == 8) && (c->dstBpc <= 14)) {
-            if (c->chrDstW % 16 == 0)
+            if (c->chrDstW % 4 == 0)
                 ASSIGN_AVX2_SCALE_FUNC(c->hcScale, c->hChrFilterSize);
-            if (c->dstW % 16 == 0)
+            if (c->dstW % 4 == 0)
                 ASSIGN_AVX2_SCALE_FUNC(c->hyScale, c->hLumFilterSize);
         }
     }
-- 
2.34.1.575.g55b058a8bb-goog