avcodec/libxvid: make 4 the default for me_quality

This will make the default behavior the same as it was with me_method.

libavcodec/libxvid.c

@@ -938,7 +938,7 @@ static const AVOption options[] = {
     { "frame",       NULL,                                                0, AV_OPT_TYPE_CONST, { .i64 = 2 }, INT_MIN, INT_MAX, VE, "ssim" },
     { "ssim_acc",    "SSIM accuracy",                   OFFSET(ssim_acc),    AV_OPT_TYPE_INT,   { .i64 = 2 },       0,       4, VE         },
     { "gmc",         "use GMC",                         OFFSET(gmc),         AV_OPT_TYPE_INT,   { .i64 = 0 },       0,       1, VE         },
-    { "me_quality",  "Motion estimation quality",       OFFSET(me_quality),  AV_OPT_TYPE_INT,   { .i64 = 0 },       0,       6, VE         },
+    { "me_quality",  "Motion estimation quality",       OFFSET(me_quality),  AV_OPT_TYPE_INT,   { .i64 = 4 },       0,       6, VE         },
     { "mpeg_quant",  "Use MPEG quantizers instead of H.263", OFFSET(mpeg_quant), AV_OPT_TYPE_INT, { .i64 = 0 },     0,       1, VE         },
     { NULL },
 };