avcodec/libx264: add me_method alias to set X264Context->motion_est

Replaces the now dropped global option.

Addresses ticket #6771.
Reviewed-by: Paul B Mahol <onemda@gmail.com>
Signed-off-by: James Almer <jamrial@gmail.com>

libavcodec/libx264.c

@@ -958,6 +958,7 @@ static const AVOption options[] = {
     { "vbr",           NULL, 0, AV_OPT_TYPE_CONST, {.i64 = X264_NAL_HRD_VBR},  INT_MIN, INT_MAX, VE, "nal-hrd" },
     { "cbr",           NULL, 0, AV_OPT_TYPE_CONST, {.i64 = X264_NAL_HRD_CBR},  INT_MIN, INT_MAX, VE, "nal-hrd" },
     { "avcintra-class","AVC-Intra class 50/100/200",                      OFFSET(avcintra_class),AV_OPT_TYPE_INT,     { .i64 = -1 }, -1, 200   , VE},
+    { "me_method",    "Set motion estimation method",                     OFFSET(motion_est),    AV_OPT_TYPE_INT,    { .i64 = -1 }, -1, X264_ME_TESA, VE, "motion-est"},
     { "motion-est",   "Set motion estimation method",                     OFFSET(motion_est),    AV_OPT_TYPE_INT,    { .i64 = -1 }, -1, X264_ME_TESA, VE, "motion-est"},
     { "dia",           NULL, 0, AV_OPT_TYPE_CONST, { .i64 = X264_ME_DIA },  INT_MIN, INT_MAX, VE, "motion-est" },
     { "hex",           NULL, 0, AV_OPT_TYPE_CONST, { .i64 = X264_ME_HEX },  INT_MIN, INT_MAX, VE, "motion-est" },