Document --detect-speed-patient.

Signed-off-by: Stefan Westerfeld <stefan@space.twc.de>

README.adoc

@@ -137,6 +137,7 @@ Use watermarking key from file <filename> (see <<key>>).
 Set the watermarking strength (see <<strength>>).
 
 --detect-speed::
+--detect-speed-patient::
 Detect and correct replay speed difference (see <<speed>>).
 
 --json <file>::
@@ -302,6 +303,10 @@ the search is automatically run in parallel using many threads on systems with
 many cpu cores. So on good hardware it makes sense to always enable this option
 to be robust to replay speed attacks.
 
+There are two versions of the speed detection algorithm, `--detect-speed` and
+`--detect-speed-patient`. The difference is that the patient version takes
+more cpu time to detect the speed, but produces more accurate results.
+
 == Short Payload (experimental)
 
 By default, the watermark will store a 128-bit message. In this mode, we

src/TODO

 release todo:
 - provide better diagnostics for command line options
-- document --detect-speed-patient
 - merge infinite wav header generator
 - make check
 
 speed detection possible improvements:
+- would n-best search make detect-speed-patient better?
 - refine with 128 sync step instead of 256?
 - detect silence instead of total volume?
 - split big region into two smaller ones?