[#1796] Computing time optimization (samplerate conversion)

sflphone-common/src/samplerateconverter.cpp

@@ -82,6 +82,21 @@ void SamplerateConverter::init (void)
 	_floatBufferUpSpkr = new float32[nbSamplesMax];
 }
 
+	void
+SamplerateConverter::Short2FloatArray (const short *in, float *out, int len)
+{
+	// factor is 1/(2^15), used to rescale the short int range to the
+	// [-1.0 - 1.0] float range.
+#define S2F_FACTOR .000030517578125f;
+
+	while (len)
+	{
+		len--;
+		out[len] = (float) in[len] * S2F_FACTOR;
+	}
+}
+
+
 //TODO Add ifdef for int16 or float32 type
 int SamplerateConverter::upsampleData (SFLDataFormat* dataIn , SFLDataFormat* dataOut, int samplerate1 , int samplerate2 , int nbSamples)
 {
@@ -99,7 +114,9 @@ int SamplerateConverter::upsampleData (SFLDataFormat* dataIn , SFLDataFormat* da
 		src_data.src_ratio = upsampleFactor;
 		src_data.end_of_input = 0; // More data will come
 		//_debug("upsample %d %d %f %d\n" , src_data.input_frames , src_data.output_frames, src_data.src_ratio , nbSamples);
-        src_short_to_float_array (dataIn , _floatBufferDownSpkr, nbSamples);
+		// Override libsamplerate conversion function
+		Short2FloatArray (dataIn , _floatBufferDownSpkr, nbSamples);
+		//src_short_to_float_array (dataIn , _floatBufferDownSpkr, nbSamples);
 		//_debug("upsample %d %f %d\n" ,  src_data.output_frames, src_data.src_ratio , nbSamples);
 		src_process (_src_state_spkr, &src_data);
 		//_debug("upsample %d %d %d\n" , samplerate1, samplerate2 , nbSamples);
@@ -128,7 +145,9 @@ int SamplerateConverter::downsampleData (SFLDataFormat* dataIn , SFLDataFormat*
 		src_data.src_ratio = downsampleFactor;
 		src_data.end_of_input = 0; // More data will come
 		//_debug("downsample %d %f %d\n" ,  src_data.output_frames, src_data.src_ratio , nbSamples);
-        src_short_to_float_array (dataIn, _floatBufferUpMic, nbSamples);
+		// Override libsamplerate conversion function
+		Short2FloatArray (dataIn , _floatBufferUpMic, nbSamples);
+		//src_short_to_float_array (dataIn, _floatBufferUpMic, nbSamples);
 		//_debug("downsample %d %f %d\n" ,  src_data.output_frames, src_data.src_ratio , nbSamples);
 		src_process (_src_state_mic, &src_data);
 		//_debug("downsample %d %f %d\n" ,  src_data.output_frames, src_data.src_ratio , nbSamples);

sflphone-common/src/samplerateconverter.h

@@ -57,6 +57,15 @@ class SamplerateConverter {
 
 		int getFramesize( void ) { return _framesize; } 
 
+		/**
+		 * Convert short table to floats for audio processing
+		 * @param in the input (short) array
+		 * @param out The resulting (float) array
+		 * @param len The number of elements in both tables
+		 */
+		void Short2FloatArray (const short *in, float *out, int len);
+
+
 	private:
 		// Copy Constructor
 		SamplerateConverter(const SamplerateConverter& rh);