Add --detect-speed-slow option for cpu intensive but more reliable search.

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

src/audiowmark.cc

@@ -592,6 +592,10 @@ parse_get_options (ArgParser& ap)
     {
       Params::detect_speed = true;
     }
+  if (ap.parse_opt ("--detect-speed-slow"))
+    {
+      Params::detect_speed_slow = true;
+    }
   if (ap.parse_opt ("--detect-speed-hint", f))
     {
       Params::detect_speed_hint = f;

src/wmcommon.cc

@@ -26,6 +26,7 @@ bool   Params::mix             = true;
 bool   Params::hard            = false; // hard decode bits? (soft decoding is better)
 bool   Params::snr             = false; // compute/show snr while adding watermark
 bool   Params::detect_speed    = false;
+bool   Params::detect_speed_slow = false;
 double Params::detect_speed_hint = -1;
 int    Params::have_key        = 0;
 size_t Params::payload_size    = 128;

src/wmcommon.hh

@@ -44,6 +44,7 @@ public:
   static           int  have_key;
 
   static           bool detect_speed;
+  static           bool detect_speed_slow;
   static           double detect_speed_hint;       // for debugging --detect-speed
 
   static           size_t payload_size;            // number of payload bits for the watermark

src/wmget.cc

@@ -1201,26 +1201,31 @@ decode_and_report (const WavData& in_data, const string& orig_pattern)
 {
 
   WavData wav_data;
-  if (Params::detect_speed)
+  if (Params::detect_speed || Params::detect_speed_slow)
     {
       double speed;
-      /* first pass:  find approximation for speed */
-      speed = speed_scan (in_data);
-
-      /* SLOW */
-      // speed = detect_speed (in_data, 1.0, 1.001,     /* steps */ 200, /* seconds */ 15);
+      if (Params::detect_speed_slow) /* SLOW */
+        {
+          /* first pass:  find approximation for speed */
+          speed = detect_speed (in_data, 1.0, 1.001, /* steps */ 200, /* seconds */ 15, nullptr);
 
-      /* second pass: fast refine (not always perfect) */
-      SpeedSync speed_sync;
-      auto scores = speed_sync.search (in_data, speed, 1.00005, 20, /* seconds */ 50);
-      sort (scores.begin(), scores.end(), [] (SpeedSync::Score s_a, SpeedSync::Score s_b) { return s_a.quality > s_b.quality; });
-      if (!scores.empty())
-        speed = scores[0].speed;
-      printf ("## speed refined %f\n", speed);
+          /* second pass: refine speed */
+          speed = detect_speed (in_data, speed, 1.00005, /* steps */ 20,  /* seconds */ 50, nullptr);
+        }
+      else /* better performance, less accurate */
+        {
+          /* first pass:  find approximation for speed */
+          speed = speed_scan (in_data);
+
+          /* second pass: fast refine (not always perfect) */
+          SpeedSync speed_sync;
+          auto scores = speed_sync.search (in_data, speed, 1.00005, 20, /* seconds */ 50);
+          sort (scores.begin(), scores.end(), [] (SpeedSync::Score s_a, SpeedSync::Score s_b) { return s_a.quality > s_b.quality; });
+          if (!scores.empty())
+            speed = scores[0].speed;
+        }
       printf ("## delta %.5f %%\n", 100 * fabs (speed - Params::detect_speed_hint) / Params::detect_speed_hint);
-
-      /* SLOW */
-      // speed = detect_speed (in_data, speed, 1.00005, /* steps */ 20,  /* seconds */ 50);
+      printf ("## speed refined %f\n", speed);
 
       int r = Params::mark_sample_rate * speed;
       if (r != Params::mark_sample_rate)