Fix MSVC compiling issues

Change-Id: Ife05a0d322fe951c2539e353b130e7b17e3ec660

av1/decoder/obu.c

diff --git a/av1/decoder/obu.c b/av1/decoder/obu.c
index e182e50..3221eab 100644
--- a/av1/decoder/obu.c
+++ b/av1/decoder/obu.c
@@ -405,7 +405,7 @@
   uint8_t *dst8 = dst->buffers[plane] + vstart2 * dst_stride + hstart2;
 
   for (row = vstart1; row < vend1; ++row) {
-    for (col = 0; col < (hend1 - hstart1); ++col) *dst8++ = *src16++;
+    for (col = 0; col < (hend1 - hstart1); ++col) *dst8++ = (uint8_t)(*src16++);
     src16 += src_stride - (hend1 - hstart1);
     dst8 += dst_stride - (hend1 - hstart1);
   }