--- a/doc/Binary-file-format	Sun Dec 11 05:12:02 2022 +0000
+++ b/doc/Binary-file-format	Sun Dec 11 05:24:11 2022 +0000
@@ -15,12 +15,18 @@
 tells us how many more bytes need to be read, and frame synchronization is thus
 maintained.
 
-FR and EFR frames are not expected to be mixed in the same stream recording;
-our low-level binary file reading function will grok such mixing just fine, but
-each higher-level test program is expected to be written for only one codec,
-either FR or EFR.
-
 The recommended filename suffix for extended-libgsm binary files in the present
 format is .gsmx; of course dot-separated filename suffixes hold absolutely no
 special meaning on Unix systems, but many developers still strongly prefer to
 have them for psychological comfort.
+
+Any gsmx file (FR or EFR) can be dumped in human-readable form with our
+gsmrec-dump utility.  This utility turns every read frame from bytes into codec
+parameters with gsm_explode() or EFR_frame2params(), and then displays those
+parameters in a sensible manner, with a per-frame header line followed by 4
+lines of subframe parameters.
+
+FR and EFR frames are not expected to be mixed in the same stream recording;
+our low-level binary file reading function and gsmrec-dump will grok such mixing
+just fine, but each higher-level test program (beyond gsmrec-dump) is expected
+to be written for only one codec, either FR or EFR.