diff --git a/cpdfmanual.pdf b/cpdfmanual.pdf
index 19b5d41..192f1ea 100644
Binary files a/cpdfmanual.pdf and b/cpdfmanual.pdf differ
diff --git a/cpdfmanual.tex b/cpdfmanual.tex
index 8b6fc60..15e950f 100644
--- a/cpdfmanual.tex
+++ b/cpdfmanual.tex
@@ -2873,7 +2873,7 @@ The \texttt{-chop} operation cuts up a page into multiple pages, according to th
     \noindent Chop each page into six.
   \end{framed}
 
-\noindent By default, the pieces are arranged in the output file row by row, and from left to right on each row. To alter this, add one or more of \texttt{-chop-columns}, \texttt{-chop-rtl} (right to left), and \texttt{-chop-btt} (bottom to top).
+\noindent The crop box is used if present; if not, the media box. By default, the pieces are arranged in the output file row by row, and from left to right on each row. To alter this, add one or more of \texttt{-chop-columns}, \texttt{-chop-rtl} (right to left), and \texttt{-chop-btt} (bottom to top).
 
 As an alternative, pages can be chopped into two at a given position, horizontally with \texttt{-chop-h} or vertically with \texttt{-chop-v}:
 
diff --git a/cpdfmetadata.mli b/cpdfmetadata.mli
index 20713c6..5d4c6a1 100644
--- a/cpdfmetadata.mli
+++ b/cpdfmetadata.mli
@@ -84,3 +84,5 @@ val expand_date : string -> string
 val get_catalog_item : string -> Pdf.t -> string
 
 val get_viewer_pref_item : string -> Pdf.t -> string
+
+val determine_subformats : Pdf.t -> string list