diff --git a/aegisub/src/agi_pre.h b/aegisub/src/agi_pre.h
index d516c2571..5e7500332 100644
--- a/aegisub/src/agi_pre.h
+++ b/aegisub/src/agi_pre.h
@@ -86,6 +86,7 @@
 #include <tr1/memory>
 #endif
 
+#define __STDC_FORMAT_MACROS
 // General headers
 #include <assert.h>
 #include <ctype.h>
diff --git a/aegisub/src/ffmpegsource_common.cpp b/aegisub/src/ffmpegsource_common.cpp
index e4b474c69..b41d2033c 100644
--- a/aegisub/src/ffmpegsource_common.cpp
+++ b/aegisub/src/ffmpegsource_common.cpp
@@ -39,6 +39,7 @@
 #ifdef WITH_FFMPEGSOURCE
 
 #ifndef AGI_PRE
+#define __STDC_FORMAT_MACROS
 #include <inttypes.h>
 #include <map>