libmyth/audio/freesurround*: silence -Wshadow

freesurround_decoder.cpp: This was identical to a code block before the if.

freesurround.cpp:

The fsurround_params constructor is never called explicitly, so just set
the default values in the struct definition.  Those values are immediately
overwritten in the FreeSurround constructor anyways.

In FreeSurround::putFrames(), copy the shadowed variables into the places
they are used.

mythtv/libs/libmyth/audio/freesurround.cpp

@@ -127,13 +127,6 @@ void FreeSurround::SetParams()
     }
 }
 
-FreeSurround::fsurround_params::fsurround_params(int32_t center_width,
-                                                 int32_t dimension) :
-    center_width(center_width),
-    dimension(dimension)
-{
-}
-
 FreeSurround::~FreeSurround()
 {
     LOG(VB_AUDIO, LOG_DEBUG, QString("FreeSurround::~FreeSurround"));
@@ -152,10 +145,6 @@ uint FreeSurround::putFrames(void* buffer, uint numFrames, uint numChannels)
     auto *samples = (float *)buffer;
     // demultiplex
 
-    float **inputs = m_decoder->getInputBuffers();
-    float *lt      = &inputs[0][ic];
-    float *rt      = &inputs[1][ic];
-
     if ((m_surroundMode != SurroundModePassive) && (ic+numFrames > bs))
     {
         numFrames = bs - ic;
@@ -178,6 +167,9 @@ uint FreeSurround::putFrames(void* buffer, uint numFrames, uint numChannels)
                     process = false;
                     break;
                 default:
+                    float **inputs = m_decoder->getInputBuffers();
+                    float *lt      = &inputs[0][ic];
+                    float *rt      = &inputs[1][ic];
                     for (i=0; i<numFrames; i++)
                         *lt++ = *rt++ = *samples++;
                     process = true;
@@ -217,6 +209,9 @@ uint FreeSurround::putFrames(void* buffer, uint numFrames, uint numChannels)
                     process = false;
                     break;
                 default:
+                    float **inputs = m_decoder->getInputBuffers();
+                    float *lt      = &inputs[0][ic];
+                    float *rt      = &inputs[1][ic];
                     for (i=0; i<numFrames; i++)
                     {
                         *lt++ = *samples++;

mythtv/libs/libmyth/audio/freesurround.h

@@ -63,16 +63,14 @@ class FreeSurround
 
     // the changeable parameters
     struct fsurround_params {
-        int32_t center_width;           // presence of the center channel
-        int32_t dimension;              // dimension
+        int32_t center_width { 100 };   // presence of the center channel
+        int32_t dimension {      0 };   // dimension
         float   coeff_a   { 0.8165 };   // surround mixing coefficients
         float   coeff_b   { 0.5774 };   // surround mixing coefficients
         int32_t phasemode {      0 };   // phase shifting mode
         int32_t steering  {      1 };   // steering mode (0=simple, 1=linear)
         int32_t front_sep {    100 };   // front stereo separation
         int32_t rear_sep  {    100 };   // rear stereo separation
-        // (default) constructor
-        explicit fsurround_params(int32_t center_width=100, int32_t dimension=0);
     } m_params;
 
     // additional settings

mythtv/libs/libmyth/audio/freesurround_decoder.cpp

@@ -278,13 +278,6 @@ class fsurround_decoder::Impl {
             } else {
                 // --- this is the old & simple steering mode ---
 
-                // calculate the amplitude/phase difference
-                float ampDiff = clamp_unit_mag((ampL+ampR < epsilon) ? 0 : (ampR-ampL) / (ampR+ampL));
-                float phaseDiff = phaseL - phaseR;
-                if (phaseDiff < -PI) phaseDiff += 2*PI;
-                if (phaseDiff > PI) phaseDiff -= 2*PI;
-                phaseDiff = abs(phaseDiff);
-
                 // determine sound field x-position
                 m_xFs[f] = ampDiff;