commit 824a93aef8992b0cbfb7c689a3a9a3b32000541b
parent f3b25056efb53f2d4c56a27c4cec0ed98614ce6a
Author: fundamental <[email protected]>
Date: Fri, 18 Dec 2009 13:21:27 -0500
Misc: Added appending and resampling to Samples
Diffstat:
3 files changed, 106 insertions(+), 3 deletions(-)
diff --git a/src/Samples/Sample.cpp b/src/Samples/Sample.cpp
@@ -19,8 +19,10 @@
Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <cmath>
+#include <cstring>//for memcpy/memset
#include "Sample.h"
+#warning TODO Think about renaming Sample to Frame
/**\TODO start using pointer math here as these will be Frequency called
* functions throughout the code*/
Sample::Sample(const Sample &smp)
@@ -92,6 +94,74 @@ bool Sample::operator==(const Sample &smp) const
return true;
}
+/**
+ * Linear point estimation
+ * @param ya Y of point a
+ * @param yb Y of point b
+ * @param xt X of test point
+ * @param xa X of point a
+ * @param xb X of point b
+ * @return estimated Y of test point
+ */
+float linearEstimate(float ya, float yb, float xt, float xa = 0.0, float xb =1.0)
+{
+#warning TODO this could be done with a good bit less computation
+ //Lets make this simple by normalizing the x axis
+
+ //Normalize point a
+ xb -= xa;
+ xt -= xa;
+ xa -= xa;
+
+ //Normalize point b
+ xt /= xb;
+ xb /= xb;
+
+ //Now xa=0 xb=1 0<=xt<=1
+ //simpily use y=mx+b
+ return (yb-ya) * xt + ya;
+}
+
+
+void Sample::resample(const unsigned int rate, const unsigned int nrate)
+{
+ if(rate == nrate)
+ return; //no resampling here
+ else {//resampling occurs here
+ int itr = 0;
+ float ratio = (nrate * 1.0) / (rate * 1.0);
+
+ int nBufferSize = (int)bufferSize * ratio;
+ float *nBuffer = new float[nBufferSize];
+
+ //addition is done to avoid 0 edge case
+ for(int i = 0; i < nBufferSize; ++i)
+ nBuffer[i] = linearEstimate(buffer[(int)floor(i/ratio)],
+ buffer[(int)ceil((i+1)/ratio)],
+ i,
+ floor(i/ratio),
+ ceil((i+1)/ratio));
+
+ //put the new data in
+ delete buffer;
+ buffer = nBuffer;
+ bufferSize = nBufferSize;
+ }
+}
+
+void Sample::append(const Sample &smp)
+{
+ int nbufferSize = bufferSize + smp.bufferSize;
+ float *nbuffer = new float[nbufferSize];
+
+ memcpy(nbuffer, buffer, bufferSize * sizeof(float));
+ memcpy(nbuffer + bufferSize, smp.buffer, smp.bufferSize * sizeof(float));
+ delete buffer;
+
+ buffer = nbuffer;
+ bufferSize = nbufferSize;
+}
+
REALTYPE Sample::max() const
{
REALTYPE max = -1500; //a good low considering that samples should store values -1.0 to 1.0
diff --git a/src/Samples/Sample.h b/src/Samples/Sample.h
@@ -50,13 +50,19 @@ class Sample
void operator=(const Sample &smp);
/**Provides the == operator*/
bool operator==(const Sample &smp) const;
+
/**Provides direct access to the buffer to allow for transition
*
* This method is like c_str() from the string class and should be used
* sparingly*/
- const REALTYPE *c_buf() {
- return buffer;
- }
+ const REALTYPE *c_buf() const {return buffer;}
+
+ /**Change the sampling rate of the Sample*/
+ void resample(const unsigned int rate, const unsigned int nrate);
+
+ /**Appends another Sample to this Sample*/
+ void append(const Sample &smp);
+
REALTYPE max() const;
REALTYPE min() const;
REALTYPE absMax() const;
diff --git a/src/Tests/SampleTest.h b/src/Tests/SampleTest.h
@@ -71,5 +71,32 @@ class SampleTest:public CxxTest::TestSuite
for(int i = 0; i < 50; ++i)
TS_ASSERT_EQUALS(smp[i], 0);
}
+
+ void testAppend() {
+ Sample smp1(54, 2);
+ Sample smp2(20, 17);
+ smp1.append(smp2);
+ TS_ASSERT_EQUALS(smp1.size(), 74);
+ for(int i = 0; i < 74; ++i)
+ TS_ASSERT_DELTA(smp1[i], (i < 54 ? 2 : 17), 0.001);
+ }
+
+ void testResample() {
+ Sample orig(32,2);
+ Sample cpy(orig);
+
+ //test for no resampleing
+ orig.resample(128,128);
+ TS_ASSERT_EQUALS(cpy,orig);
+
+ //test for no bad distortions
+ orig.resample(128,256);
+ orig.resample(256,128);
+ TS_ASSERT_EQUALS(cpy,orig);
+
+ //test for downsample
+ orig.resample(256,128);
+ TS_ASSERT_EQUALS(orig.size(),cpy.size()/2);
+ }
};
