* Add OptionThreadingAlways

rubberband/RubberBandStretcher.h

@@ -122,10 +122,15 @@ public:
      *
      *   OptionThreadingAuto - Permit the stretcher to determine its
      *   own threading model.  Usually this means using one processing
-     *   thread per audio channel in offline mode, and one thread only
+     *   thread per audio channel in offline mode if the stretcher is
-     *   in realtime mode.
+     *   able to determine that more than one CPU is available, and
+     *   one thread only in realtime mode.
      *
-     *   OptionThreadingNone - Never use more than one thread.
+     *   OptionThreadingNever - Never use more than one thread.
+     *  
+     *   OptionThreadingAlways - Use multiple threads in any situation
+     *   where OptionThreadingAuto would do so, except omit the check
+     *   for multiple CPUs and instead assume it to be true.
      *
      * 6. Options prefixed OptionWindow control the window size for
      * FFT processing.  The window size actually used will depend on
@@ -162,7 +167,8 @@ public:
     static const int OptionPhaseIndependent = 0x00002000;
     
     static const int OptionThreadingAuto    = 0x00000000;
-    static const int OptionThreadingNone    = 0x00010000;
+    static const int OptionThreadingNever   = 0x00010000;
+    static const int OptionThreadingAlways  = 0x00020000;
 
     static const int OptionWindowStandard   = 0x00000000;
     static const int OptionWindowShort      = 0x00100000;

src/StretcherImpl.cpp

@@ -119,16 +119,19 @@ RubberBandStretcher::Impl::Impl(RubberBandStretcher *stretcher,
 
     if (m_channels > 1) {
 
-        if (!m_realtime &&
+        m_threaded = true;
-            !(m_options & OptionThreadingNone) &&
-            Thread::threadingAvailable() &&
-            system_is_multiprocessor()) {
 
-            m_threaded = true;
+        if (m_realtime) {
-        
+            m_threaded = false;
-            if (m_debugLevel > 0) {
+        } else if (m_options & OptionThreadingNever) {
-                cerr << "Going multithreaded..." << endl;
+            m_threaded = false;
-            }
+        } else if (!(m_options & OptionThreadingAlways) &&
+                   !system_is_multiprocessor()) {
+            m_threaded = false;
+        }
+
+        if (m_threaded && m_debugLevel > 0) {
+            cerr << "Going multithreaded..." << endl;
         }
     }
 

src/main.cpp

@@ -38,7 +38,7 @@ int main(int argc, char **argv)
     int debug = 0;
     bool realtime = false;
     bool precise = false;
-    bool threaded = true;
+    int threading = 0;
     bool peaklock = true;
     bool longwin = false;
     bool shortwin = false;
@@ -83,6 +83,7 @@ int main(int argc, char **argv)
             { "thresh2",       1, 0, '7' },
             { "bl-transients", 0, 0, '8' },
             { "no-softening",  0, 0, '9' },
+            { "threads",       0, 0, '@' },
             { "quiet",         0, 0, 'q' },
             { 0, 0, 0 }
         };
@@ -99,7 +100,8 @@ int main(int argc, char **argv)
         case 'd': debug = atoi(optarg); break;
         case 'R': realtime = true; break;
         case 'P': precise = true; break;
-        case '0': threaded = false; break;
+        case '0': threading = 1; break;
+        case '@': threading = 2; break;
         case '1': transients = NoTransients; break;
         case '2': peaklock = false; break;
         case '3': longwin = true; break;
@@ -143,7 +145,8 @@ int main(int argc, char **argv)
         cerr << endl;
         cerr << "  -P,    --precise        Aim for minimal time distortion (implied by -R)" << endl;
         cerr << "  -R,    --realtime       Select realtime mode (implies -P --no-threads)" << endl;
-        cerr << "         --no-threads     No extra threads regardless of cpus/channel count" << endl;
+        cerr << "         --no-threads     No extra threads regardless of CPU and channel count" << endl;
+        cerr << "         --threads        Assume multi-CPU even if only one CPU is identified" << endl;
         cerr << "         --no-transients  Disable phase resynchronisation at transients" << endl;
         cerr << "         --bl-transients  Band-limit phase resync to extreme frequencies" << endl;
         cerr << "         --no-peaklock    Disable phase locking to peak frequencies" << endl;
@@ -217,10 +220,21 @@ int main(int argc, char **argv)
     if (precise)     options |= RubberBandStretcher::OptionStretchPrecise;
     if (!peaklock)   options |= RubberBandStretcher::OptionPhaseIndependent;
     if (!softening)  options |= RubberBandStretcher::OptionPhasePeakLocked;
-    if (!threaded)   options |= RubberBandStretcher::OptionThreadingNone;
     if (longwin)     options |= RubberBandStretcher::OptionWindowLong;
     if (shortwin)    options |= RubberBandStretcher::OptionWindowShort;
 
+    switch (threading) {
+    case 0:
+        options |= RubberBandStretcher::OptionThreadingAuto;
+        break;
+    case 1:
+        options |= RubberBandStretcher::OptionThreadingNever;
+        break;
+    case 2:
+        options |= RubberBandStretcher::OptionThreadingAlways;
+        break;
+    }
+
     switch (transients) {
     case NoTransients:
         options |= RubberBandStretcher::OptionTransientsSmooth;