diff --git a/libavformat/avc.h b/libavformat/avc.h
index 364c69f629..2deb77df15 100644
--- a/libavformat/avc.h
+++ b/libavformat/avc.h
@@ -25,7 +25,7 @@
 #include <stdint.h>
 #include "avio.h"
 
-int ff_avc_parse_nal_units(const uint8_t *buf_in, uint8_t **buf, int size);
+int ff_avc_parse_nal_units(ByteIOContext *s, const uint8_t *buf, int size);
 int ff_avc_parse_nal_units_buf(const uint8_t *buf_in, uint8_t **buf, int *size);
 int ff_isom_write_avcc(ByteIOContext *pb, const uint8_t *data, int len);
 const uint8_t *ff_avc_find_startcode(const uint8_t *p, const uint8_t *end);