diff --git a/avilib-0.6.10/avilib.h b/avilib-0.6.10/avilib.h
index 21bf46726..c48611d1a 100644
--- a/avilib-0.6.10/avilib.h
+++ b/avilib-0.6.10/avilib.h
@@ -162,6 +162,8 @@ typedef struct
   uint32_t  bi_clr_important;
 } alBITMAPINFOHEADER;
 
+#pragma pack(2)
+
 typedef struct
 {
   uint16_t  w_format_tag;
@@ -173,6 +175,8 @@ typedef struct
   uint16_t  cb_size;
 } alWAVEFORMATEX;
 
+#pragma pack(4)
+
 typedef struct
 {
   uint32_t fcc_type; 
diff --git a/avilib/avilib.h b/avilib/avilib.h
index 230845ea1..d72729f8b 100644
--- a/avilib/avilib.h
+++ b/avilib/avilib.h
@@ -100,6 +100,8 @@ typedef struct
   uint32_t  bi_clr_important;
 } alBITMAPINFOHEADER;
 
+#pragma pack(2)
+
 typedef struct
 {
   uint16_t  w_format_tag;
@@ -111,6 +113,8 @@ typedef struct
   uint16_t  cb_size;
 } alWAVEFORMATEX;
 
+#pragma pack(4)
+
 typedef struct
 {
   uint32_t fcc_type;