diff --git a/tools/qt-faststart.c b/tools/qt-faststart.c
index b1917f18ef..b9dbdfdb6a 100644
--- a/tools/qt-faststart.c
+++ b/tools/qt-faststart.c
@@ -303,10 +303,7 @@ int main(int argc, char *argv[])
     }
     printf(" copying rest of file...\n");
     while (last_offset) {
-        if (last_offset > COPY_BUFFER_SIZE)
-            bytes_to_copy = COPY_BUFFER_SIZE;
-        else
-            bytes_to_copy = last_offset;
+        bytes_to_copy = FFMIN(bytes_to_copy, last_offset);
 
         if (fread(copy_buffer, bytes_to_copy, 1, infile) != 1) {
             perror(argv[1]);