diff --git a/avilib-0.6.10/xio.cpp b/avilib-0.6.10/xio.cpp
index 5fca59c42..c8bdda192 100644
--- a/avilib-0.6.10/xio.cpp
+++ b/avilib-0.6.10/xio.cpp
@@ -97,21 +97,21 @@ xio_write(int fd,
 
 int
 xio_ftruncate(int fd,
-              off_t length) {
+              int64_t length) {
   if ((fd < 0) || (fd >= MAX_INSTANCES) || (instances[fd] == NULL))
     return -1;
   return instances[fd]->truncate(length);
 }
 
-off_t
+int64_t
 xio_lseek(int fd,
-          off_t offset,
+          int64_t offset,
           int whence) {
   int64_t expected_pos;
   seek_mode smode;
 
   if ((fd < 0) || (fd >= MAX_INSTANCES) || (instances[fd] == NULL))
-    return (off_t)-1;
+    return (int64_t)-1;
   if (whence == SEEK_SET) {
     smode = seek_beginning;
     expected_pos = offset;
@@ -124,7 +124,7 @@ xio_lseek(int fd,
   }
   instances[fd]->setFilePointer(offset, smode);
   if (instances[fd]->getFilePointer() != expected_pos)
-    return (off_t)-1;
+    return (int64_t)-1;
   return expected_pos;
 }
 
diff --git a/avilib-0.6.10/xio.h b/avilib-0.6.10/xio.h
index ae7cad5f3..01bdb6188 100644
--- a/avilib-0.6.10/xio.h
+++ b/avilib-0.6.10/xio.h
@@ -34,8 +34,8 @@ extern "C" {
 int xio_open(const char *pathname, int flags, ...);
 ssize_t xio_read(int fd, void *buf, size_t count);
 ssize_t xio_write(int fd, const void *buf, size_t count);
-int xio_ftruncate(int fd, off_t length);
-off_t xio_lseek(int fd, off_t offset, int whence);
+int xio_ftruncate(int fd, int64_t length);
+int64_t xio_lseek(int fd, int64_t offset, int whence);
 int xio_close(int fd);
 int xio_fstat(int fd, struct stat *buf);
 int xio_lstat(const char *filename, struct stat *buf);