refmvs: Pack the refmvs_block struct

Reduces size from 16B to 12B, while maintaining a 4-byte alignment.

3 files changed, 9 insertions, 2 deletions

diff --git a/include/common/attributes.h b/include/common/attributes.h
index 64df445..4ccc421 100644
--- a/include/common/attributes.h
+++ b/include/common/attributes.h
@@ -178,4 +178,10 @@ static inline int clzll(const unsigned long long mask) {
     static_assert(name == offsetof(type, field), #field)
 #endif
 
+#ifdef _MSC_VER
+#define PACKED(...) __pragma(pack(push, 1)) __VA_ARGS__ __pragma(pack(pop))
+#else
+#define PACKED(...) __VA_ARGS__ __attribute__((__packed__))
+#endif
+
 #endif /* DAV1D_COMMON_ATTRIBUTES_H */
diff --git a/src/levels.h b/src/levels.h
index 571c580..0f510e9 100644
--- a/src/levels.h
+++ b/src/levels.h
@@ -31,6 +31,7 @@
 #include <stdint.h>
 
 #include "dav1d/headers.h"
+#include "common/attributes.h"
 
 enum ObuMetaType {
     OBU_META_HDR_CLL     = 1,
diff --git a/src/refmvs.h b/src/refmvs.h
index 6f68a76..976d209 100644
--- a/src/refmvs.h
+++ b/src/refmvs.h
@@ -55,11 +55,11 @@ typedef union refmvs_mvpair {
     uint64_t n;
 } refmvs_mvpair;
 
-typedef struct refmvs_block {
+PACKED(typedef struct refmvs_block {
     refmvs_mvpair mv;
     refmvs_refpair ref;
     uint8_t bs, mf; // 1 = globalmv+affine, 2 = newmv
-} refmvs_block;
+}) ALIGN(refmvs_block, 4);
 
 typedef struct refmvs_frame {
     const Dav1dFrameHeader *frm_hdr;