avcodec/utvideoenc : add SIMD (avx) for sub_left_prediction

asm code by Henrik Gramner

libavcodec/lossless_videoencdsp.c

@@ -74,10 +74,25 @@ static void sub_median_pred_c(uint8_t *dst, const uint8_t *src1,
     *left_top = lt;
 }
 
+static void sub_left_predict_c(uint8_t *dst, uint8_t *src,
+                               ptrdiff_t stride, ptrdiff_t width, int height)
+{
+    int i, j;
+    uint8_t prev = 0x80; /* Set the initial value */
+    for (j = 0; j < height; j++) {
+        for (i = 0; i < width; i++) {
+            *dst++ = src[i] - prev;
+            prev   = src[i];
+        }
+        src += stride;
+    }
+}
+
 av_cold void ff_llvidencdsp_init(LLVidEncDSPContext *c)
 {
     c->diff_bytes      = diff_bytes_c;
     c->sub_median_pred = sub_median_pred_c;
+    c->sub_left_predict = sub_left_predict_c;
 
     if (ARCH_X86)
         ff_llvidencdsp_init_x86(c);

libavcodec/lossless_videoencdsp.h

@@ -21,6 +21,8 @@
 
 #include <stdint.h>
 
+#include "avcodec.h"
+
 typedef struct LLVidEncDSPContext {
     void (*diff_bytes)(uint8_t *dst /* align 16 */,
                        const uint8_t *src1 /* align 16 */,
@@ -33,6 +35,9 @@ typedef struct LLVidEncDSPContext {
     void (*sub_median_pred)(uint8_t *dst, const uint8_t *src1,
                             const uint8_t *src2, intptr_t w,
                             int *left, int *left_top);
+
+    void (*sub_left_predict)(uint8_t *dst, uint8_t *src,
+                          ptrdiff_t stride, ptrdiff_t width, int height);
 } LLVidEncDSPContext;
 
 void ff_llvidencdsp_init(LLVidEncDSPContext *c);

libavcodec/utvideoenc.c

@@ -283,23 +283,6 @@ static void mangle_rgb_planes(uint8_t *dst[4], ptrdiff_t dst_stride,
     }
 }
 
-/* Write data to a plane with left prediction */
-static void left_predict(uint8_t *src, uint8_t *dst, ptrdiff_t stride,
-                         int width, int height)
-{
-    int i, j;
-    uint8_t prev;
-
-    prev = 0x80; /* Set the initial value */
-    for (j = 0; j < height; j++) {
-        for (i = 0; i < width; i++) {
-            *dst++ = src[i] - prev;
-            prev   = src[i];
-        }
-        src += stride;
-    }
-}
-
 #undef A
 #undef B
 
@@ -436,8 +419,7 @@ static int encode_plane(AVCodecContext *avctx, uint8_t *src,
         for (i = 0; i < c->slices; i++) {
             sstart = send;
             send   = height * (i + 1) / c->slices & cmask;
-            left_predict(src + sstart * stride, dst + sstart * width,
-                         stride, width, send - sstart);
+            c->llvidencdsp.sub_left_predict(dst + sstart * width, src + sstart * stride, stride, width, send - sstart);
         }
         break;
     case PRED_MEDIAN:

libavcodec/x86/lossless_videoencdsp.asm

@@ -25,6 +25,8 @@
 
 %include "libavutil/x86/x86util.asm"
 
+cextern pb_80
+
 SECTION .text
 
 ; void ff_diff_bytes(uint8_t *dst, const uint8_t *src1, const uint8_t *src2,
@@ -149,3 +151,44 @@ DIFF_BYTES_PROLOGUE
     DIFF_BYTES_BODY    u, u
 %undef i
 %endif
+
+
+;--------------------------------------------------------------------------------------------------
+;void sub_left_predict(uint8_t *dst, uint8_t *src, ptrdiff_t stride, ptrdiff_t width, int height)
+;--------------------------------------------------------------------------------------------------
+
+INIT_XMM avx
+cglobal sub_left_predict, 5,6,5, dst, src, stride, width, height, x
+    mova             m1, [pb_80] ; prev initial
+    add            dstq, widthq
+    add            srcq, widthq
+    lea              xd, [widthq-1]
+    neg          widthq
+    and              xd, 15
+    pinsrb           m4, m1, xd, 15
+    mov              xq, widthq
+
+    .loop:
+        movu                     m0, [srcq + widthq]
+        palignr                  m2, m0, m1, 15
+        movu                     m1, [srcq + widthq + 16]
+        palignr                  m3, m1, m0, 15
+        psubb                    m2, m0, m2
+        psubb                    m3, m1, m3
+        movu        [dstq + widthq], m2
+        movu   [dstq + widthq + 16], m3
+        add                  widthq, 2 * 16
+        jl .loop
+
+    add   srcq, strideq
+    sub   dstq, xq ; dst + width
+    test    xd, 16
+    jz .mod32
+    mova    m1, m0
+
+.mod32:
+    pshufb    m1, m4
+    mov   widthq, xq
+    dec  heightd
+    jg .loop
+    RET

libavcodec/x86/lossless_videoencdsp_init.c

@@ -36,6 +36,9 @@ void ff_diff_bytes_sse2(uint8_t *dst, const uint8_t *src1, const uint8_t *src2,
 void ff_diff_bytes_avx2(uint8_t *dst, const uint8_t *src1, const uint8_t *src2,
                         intptr_t w);
 
+void ff_sub_left_predict_avx(uint8_t *dst, uint8_t *src,
+                            ptrdiff_t stride, ptrdiff_t width, int height);
+
 #if HAVE_INLINE_ASM
 
 static void sub_median_pred_mmxext(uint8_t *dst, const uint8_t *src1,
@@ -98,6 +101,10 @@ av_cold void ff_llvidencdsp_init_x86(LLVidEncDSPContext *c)
         c->diff_bytes = ff_diff_bytes_sse2;
     }
 
+    if (EXTERNAL_AVX(cpu_flags)) {
+        c->sub_left_predict = ff_sub_left_predict_avx;
+    }
+
     if (EXTERNAL_AVX2_FAST(cpu_flags)) {
         c->diff_bytes = ff_diff_bytes_avx2;
     }