prepare threshold for silence trim

diff --git a/libs/audiographer/audiographer/general/silence_trimmer.h b/libs/audiographer/audiographer/general/silence_trimmer.h
index 7e8d3c485c6e47867ab0a2e14ef9970cb9c8912f..889b891737ec3060a36edd4d50970d44078b3e58 100644 (file)
--- a/libs/audiographer/audiographer/general/silence_trimmer.h
+++ b/libs/audiographer/audiographer/general/silence_trimmer.h
@@ -12,6 +12,24 @@
 
 namespace AudioGrapher {
 
+template<typename T> struct SilenceTester;
+
+// this needs to be implemented for every datatype T
+// currently Ardour always uses Sample aka float
+template <>
+struct SilenceTester<float> {
+       public:
+       SilenceTester (const float dB) {
+               threshold = dB > -318.8f ? pow (10.0f, dB * 0.05f) : 0.0f;
+       }
+       bool is_silent (const float d) {
+               return fabsf (d) <= threshold;
+       }
+       private:
+       float threshold;
+};
+
+
 /// Removes and adds silent frames to beginning and/or end of stream
 template<typename T = DefaultSampleType>
 class /*LIBAUDIOGRAPHER_API*/ SilenceTrimmer
@@ -23,9 +41,10 @@ class /*LIBAUDIOGRAPHER_API*/ SilenceTrimmer
   public:
 
        /// Constructor, \see reset() \n Not RT safe
-       SilenceTrimmer(framecnt_t silence_buffer_size_ = 1024)
+       SilenceTrimmer(framecnt_t silence_buffer_size_ = 1024, float thresh_dB = -INFINITY)
          : silence_buffer_size (0)
          , silence_buffer (0)
+         , tester (thresh_dB)
        {
                reset (silence_buffer_size_);
                add_supported_flag (ProcessContext<T>::EndOfInput);
@@ -231,7 +250,7 @@ class /*LIBAUDIOGRAPHER_API*/ SilenceTrimmer
        bool find_first_non_zero_sample (ProcessContext<T> const & c, framecnt_t & result_frame)
        {
                for (framecnt_t i = 0; i < c.frames(); ++i) {
-                       if (c.data()[i] != static_cast<T>(0.0)) {
+                       if (!tester.is_silent (c.data()[i])) {
                                result_frame = i;
                                // Round down to nearest interleaved "frame" beginning
                                result_frame -= result_frame % c.channels();
@@ -284,6 +303,8 @@ class /*LIBAUDIOGRAPHER_API*/ SilenceTrimmer
 
        framecnt_t silence_buffer_size;
        T *        silence_buffer;
+
+       SilenceTester<T> tester;
 };
 
 } // namespace