[FFmpeg-devel] [PATCH v1] scale: Bring back the old yuv2yuvX, use it when disable-x86asm.

[heng.hu.1989 at gmail.com]

From: huheng <heng.hu.1989 at gmail.com>

rename old inline yuv2yuvX to yuv2yuv_X, to avoid conflicts with
the names of standalone asm functions. When ffmpeg is compiled with
--disable-x86asm, using the scale function will cause the video to
be blurred. The reason is that when disable-x86asm, INLINE_MMXEXT
is 1 and use_mmx_vfilter is 1, but c->yuv2planeX uses the c language
version, which causes a problem of mismatch with the vfilter. This
problem has persisted from version 4.4 to the present. Fix it by using
inline yuv2yuv_X_mmxext, that can maintain the consistency of
use_mmx_vfilter.

reproduce the issue:
1. ./configure --disable-x86asm --enable-gpl --enable-libx264
2. ./ffmpeg -i input.mp4 -vf "scale=1280x720" -c:v libx264 output.mp4
the output.mp4 is abnormal

Signed-off-by: huheng <heng.hu.1989 at gmail.com>
---
 libswscale/x86/swscale.c          |  6 +++-
 libswscale/x86/swscale_template.c | 53 +++++++++++++++++++++++++++++++
 2 files changed, 58 insertions(+), 1 deletion(-)

diff --git a/libswscale/x86/swscale.c b/libswscale/x86/swscale.c
index ff16398988..1bb9d1d51a 100644
--- a/libswscale/x86/swscale.c
+++ b/libswscale/x86/swscale.c
@@ -452,8 +452,12 @@ av_cold void ff_sws_init_swscale_x86(SwsContext *c)
     int cpu_flags = av_get_cpu_flags();
 
 #if HAVE_MMXEXT_INLINE
-    if (INLINE_MMXEXT(cpu_flags))
+    if (INLINE_MMXEXT(cpu_flags)) {
         sws_init_swscale_mmxext(c);
+        if (c->use_mmx_vfilter && !(c->flags & SWS_ACCURATE_RND)) {
+            c->yuv2planeX = yuv2yuv_X_mmxext;
+        }
+    }
 #endif
     if(c->use_mmx_vfilter && !(c->flags & SWS_ACCURATE_RND)) {
 #if HAVE_MMXEXT_EXTERNAL
diff --git a/libswscale/x86/swscale_template.c b/libswscale/x86/swscale_template.c
index 6190fcb4fe..1b8794480d 100644
--- a/libswscale/x86/swscale_template.c
+++ b/libswscale/x86/swscale_template.c
@@ -33,6 +33,59 @@
 #define MOVNTQ2 "movntq "
 #define MOVNTQ(a,b)  REAL_MOVNTQ(a,b)
 
+static void RENAME(yuv2yuv_X)(const int16_t *filter, int filterSize,
+                           const int16_t **src, uint8_t *dest, int dstW,
+                           const uint8_t *dither, int offset)
+{
+    filterSize--;
+    __asm__ volatile(
+        "movd %0, %%mm1\n\t"
+        "punpcklwd %%mm1, %%mm1\n\t"
+        "punpckldq %%mm1, %%mm1\n\t"
+        "psllw        $3, %%mm1\n\t"
+        "paddw     %%mm1, %%mm3\n\t"
+        "paddw     %%mm1, %%mm4\n\t"
+        "psraw        $4, %%mm3\n\t"
+        "psraw        $4, %%mm4\n\t"
+        ::"m"(filterSize)
+     );
+
+    __asm__ volatile(\
+        "movq    %%mm3, %%mm6\n\t"
+        "movq    %%mm4, %%mm7\n\t"
+        "movl %3, %%ecx\n\t"
+        "mov                                 %0, %%"FF_REG_d"       \n\t"\
+        "mov                        (%%"FF_REG_d"), %%"FF_REG_S"    \n\t"\
+        ".p2align                             4                     \n\t" /* FIXME Unroll? */\
+        "1:                                                         \n\t"\
+        "movq                      8(%%"FF_REG_d"), %%mm0           \n\t" /* filterCoeff */\
+        "movq                (%%"FF_REG_S", %%"FF_REG_c", 2), %%mm2 \n\t" /* srcData */\
+        "movq               8(%%"FF_REG_S", %%"FF_REG_c", 2), %%mm5 \n\t" /* srcData */\
+        "add                                $16, %%"FF_REG_d"       \n\t"\
+        "mov                        (%%"FF_REG_d"), %%"FF_REG_S"    \n\t"\
+        "test                         %%"FF_REG_S", %%"FF_REG_S"    \n\t"\
+        "pmulhw                           %%mm0, %%mm2      \n\t"\
+        "pmulhw                           %%mm0, %%mm5      \n\t"\
+        "paddw                            %%mm2, %%mm3      \n\t"\
+        "paddw                            %%mm5, %%mm4      \n\t"\
+        " jnz                                1b             \n\t"\
+        "psraw                               $3, %%mm3      \n\t"\
+        "psraw                               $3, %%mm4      \n\t"\
+        "packuswb                         %%mm4, %%mm3      \n\t"
+        MOVNTQ2 "                         %%mm3, (%1, %%"FF_REG_c")\n\t"
+        "add                          $8, %%"FF_REG_c"      \n\t"\
+        "cmp                          %2, %%"FF_REG_c"      \n\t"\
+        "movq    %%mm6, %%mm3\n\t"
+        "movq    %%mm7, %%mm4\n\t"
+        "mov                                 %0, %%"FF_REG_d"     \n\t"\
+        "mov                        (%%"FF_REG_d"), %%"FF_REG_S"  \n\t"\
+        "jb                                  1b                   \n\t"\
+        :: "g" (filter),
+           "r" (dest-offset), "g" ((x86_reg)(dstW+offset)), "m" (offset)
+        : "%"FF_REG_d, "%"FF_REG_S, "%"FF_REG_c
+    );
+}
+
 #define YSCALEYUV2PACKEDX_UV \
     __asm__ volatile(\
         "xor                %%"FF_REG_a", %%"FF_REG_a"  \n\t"\
-- 
2.20.1