FS-8875 Enable faster beep detection

Unnecessary computation of arc cosine is omitted
and convergence is checked on partial results.
Original frequency is easily retrieved when needed.

src/mod/applications/mod_avmd/Makefile.am

@@ -2,7 +2,7 @@ include $(top_srcdir)/build/modmake.rulesam
 MODNAME=mod_avmd
 
 mod_LTLIBRARIES = mod_avmd.la
-mod_avmd_la_SOURCES  = mod_avmd.c avmd_amplitude.c avmd_buffer.c avmd_desa2.c avmd_goertzel.c avmd_fast_acosf.c
+mod_avmd_la_SOURCES  = mod_avmd.c avmd_buffer.c avmd_desa2_tweaked.c avmd_fast_acosf.c
 mod_avmd_la_CFLAGS   = $(AM_CFLAGS) $(AM_MOD_AVMD_CXXFLAGS)
 mod_avmd_la_LIBADD   = $(switch_builddir)/libfreeswitch.la
 mod_avmd_la_LDFLAGS  = -avoid-version -module -no-undefined -shared

src/mod/applications/mod_avmd/avmd_amplitude.c

-#ifndef __AMPLITUDE_H__
+#ifndef __AVMD_AMPLITUDE_H__
+
+
 #include <math.h>
 #include "avmd_amplitude.h"
 #include "avmd_psi.h"
@@ -10,14 +12,13 @@
  * @param f Frequency estimate
  * @return The amplitude at position i 
  */
-extern double amplitude(circ_buffer_t *b, size_t i, double f)
+extern double avmd_amplitude(circ_buffer_t *b, size_t i, double f)
 {
     double result;
-
     result = sqrt(PSI(b, i) / sin(f * f));
-
     return result;
 }
 
-#endif
+
+#endif /* __AVMD_AMPLITUDE_H__ */
 

src/mod/applications/mod_avmd/avmd_amplitude.h

-#ifndef __AMPLITUDE_H__
-#define __AMPLITUDE_H__
-#include "avmd_buffer.h"
+/*
+ * @brief   Estimation of amplitude using DESA-2 algorithm.
+ * @author Eric des Courtis
+ * @par    Modifications: Piotr Gregor < piotrek.gregor gmail.com >
+ */
+
+
+#ifndef __AVMD_AMPLITUDE_H__
+#define __AVMD_AMPLITUDE_H__
 
-extern double amplitude(circ_buffer_t *, size_t i, double f);
+
+#include "avmd_buffer.h"
 
 
-#endif
+extern double avmd_amplitude(circ_buffer_t *, size_t i, double f);
 
 
+#endif /* __AVMD_AMPLITUDE_H__ */

src/mod/applications/mod_avmd/avmd_buffer.h

-#ifndef __BUFFER_H__
-#define __BUFFER_H__
+/*
+ * @brief   Circular buffer.
+ *
+ * @author Eric des Courtis
+ * @par    Modifications: Piotr Gregor < piotrek.gregor gmail.com >
+ */
+
+
+#ifndef __AVMD_BUFFER_H__
+#define __AVMD_BUFFER_H__
+
+
 #include <stdlib.h>
 #include <assert.h>
 
@@ -55,6 +65,10 @@ extern size_t next_power_of_2(size_t v);
 	if ((b)->backlog > (b)->buf_len) (b)->backlog = (b)->buf_len; \
     } while (0)
 
+
+/*		    ((f)[(b)->i] >= 0) ? \
+		    ((BUFF_TYPE)(f)[(b)->i] / (BUFF_TYPE)INT16_MAX): \
+		    (0.0 - ((BUFF_TYPE)(f)[(b)->i] / (BUFF_TYPE)INT16_MIN)) \ */
 #define INSERT_INT16_FRAME(b, f, l) \
     { \
 	for ((b)->i = 0; (b)->i < (l); (b)->i++) { \
@@ -62,9 +76,7 @@ extern size_t next_power_of_2(size_t v);
 		(b), \
 		((b)->i + (b)->pos), \
 		( \
-		    ((f)[(b)->i] >= 0) ? \
-		    ((BUFF_TYPE)(f)[(b)->i] / (BUFF_TYPE)INT16_MAX): \
-		    (0.0 - ((BUFF_TYPE)(f)[(b)->i] / (BUFF_TYPE)INT16_MIN)) \
+		    (BUFF_TYPE)(f)[(b)->i] \
 		) \
 	    ); \
 	} \
@@ -102,5 +114,4 @@ extern size_t next_power_of_2(size_t v);
 	SET_SAMPLE((b), GET_CURRENT_LPOS((b)), (s)); \
     } while (0)
 
-#endif
-
+#endif /* __AVMD_BUFFER_H__ */

src/mod/applications/mod_avmd/avmd_desa2.c

-#ifndef __DESA2_H__
+#ifndef __AVMD_DESA2_H__
+
+
 #include <stdio.h>
 #ifdef WIN32
 #include <float.h>
@@ -14,7 +16,7 @@
 #include "avmd_fast_acosf.h"
 #endif
 
-extern double desa2(circ_buffer_t *b, size_t i)
+extern double avmd_desa2(circ_buffer_t *b, size_t i)
 {
     double d;
     double n;
@@ -33,13 +35,10 @@ extern double desa2(circ_buffer_t *b, size_t i)
     x4 = GET_SAMPLE((b), ((i) + 4));
 
     x2sq = x2 * x2;
-
     d = 2.0 * ((x2sq) - (x1 * x3));
     if (d == 0.0) return 0.0;
-
     n = ((x2sq) - (x0 * x4)) - ((x1 * x1) - (x0 * x2)) - ((x3 * x3) - (x2 * x4));
 
-
 #ifdef AVMD_FAST_MATH
     result = 0.5 * (double)fast_acosf((float)n/d);
 #else
@@ -52,4 +51,4 @@ extern double desa2(circ_buffer_t *b, size_t i)
 
 }
 
-#endif
+#endif /* __AVMD_DESA2_H__ */

src/mod/applications/mod_avmd/avmd_desa2.h

-#ifndef __DESA2_H__
-#define __DESA2_H__
+/*
+ * @brief  DESA-2 algorithm implementation.
+ * @author Eric des Courtis
+ * @par    Modifications: Piotr Gregor < piotrek.gregor gmail.com >
+ */
+
+
+#ifndef __AVMD_DESA2_H__
+#define __AVMD_DESA2_H__
+
+
 #include <math.h>
 #include "avmd_buffer.h"
 
-extern double desa2(circ_buffer_t *b, size_t i);
-#endif
+/* Returns digital frequency estimation. */
+extern double avmd_desa2(circ_buffer_t *b, size_t i);
+
 
+#endif  /* __AVMD_DESA2_H__ */

src/mod/applications/mod_avmd/avmd_desa2_tweaked.c

+#ifndef __AVMD_DESA2_TWEAKED_H__
+
+
+#include <stdio.h>
+#ifdef WIN32
+#include <float.h>
+#define ISNAN(x) (!!(_isnan(x)))
+#else
+#define ISNAN(x) (isnan(x))
+#endif
+#include "avmd_buffer.h"
+#include "avmd_desa2_tweaked.h"
+#include "avmd_options.h"
+
+#ifdef AVMD_FAST_MATH
+#include "avmd_fast_acosf.h"
+#endif
+
+#include <switch.h>
+
+
+double
+avmd_desa2_tweaked(circ_buffer_t *b, size_t i,
+        switch_core_session_t *session)
+{
+    double d;
+    double n;
+    double x0;
+    double x1;
+    double x2;
+    double x3;
+    double x4;
+    double x2sq;
+    double result;
+
+    x0 = GET_SAMPLE((b), (i));
+    x1 = GET_SAMPLE((b), ((i) + 1));
+    x2 = GET_SAMPLE((b), ((i) + 2));
+    x3 = GET_SAMPLE((b), ((i) + 3));
+    x4 = GET_SAMPLE((b), ((i) + 4));
+    x2sq = x2 * x2;
+    d = 2.0 * ((x2sq) - (x1 * x3));
+    n = ((x2sq) - (x0 * x4)) - ((x1 * x1) 
+            - (x0 * x2)) - ((x3 * x3) - (x2 * x4));
+
+/* instead of
+#ifdef FASTMATH
+    result = 0.5 * (double)fast_acosf((float)n/d);
+#else
+    result = 0.5 * acos(n/d);
+#endif
+ we do simplified, modified for speed version : */
+
+    result = n/d;
+    if (isinf(result)) {
+        if (n < 0.0)
+            return -10.0;
+        else
+            return 10.0;
+    }
+    return result;
+}
+
+#endif  /* __AVMD_DESA2_TWEAKED_H__ */

src/mod/applications/mod_avmd/avmd_desa2_tweaked.h

+/*
+ * @brief   Estimator of cosine of digital frequency.
+ * @details It is tweaked DESA implementation which
+ *          returns partial product of DESA-2 estimation
+ *          so that arc cosine transform can be ommited
+ *          on all computations, but these values can
+ *          be checked for convergence in the same time.
+ *          If the partial results converge then frequency
+ *          converges too.
+ * @author  Piotr Gregor < piotrek.gregor gmail.com >
+ * @date    20 Mar 2016
+ */
+
+
+#ifndef __AVMD_DESA2_TWEAKED_H__
+#define __AVMD_DESA2_TWEAKED_H__
+
+
+#include <math.h>
+#include "avmd_buffer.h"
+#include <switch.h>
+
+
+/* Instead of returning digital frequency estimation using
+ *      result = 0.5 * acos(n/d),
+ * which involves expensive computation of arc cosine on
+ * each new sample, this function returns only (n/d) factor.
+ * The series of these partial DESA-2 results can be still
+ * checked for convergence, though measures and thresholds
+ * used to assess this will differ from those used for
+ * assessment of convergence of instantaneous frequency
+ * estimates since transformation of tweaked results
+ * to corresponding frequencies is nonlinear.
+ * The actual frequency estimation can be retrieved later
+ * from this partial result using
+ *      0.5 * acos(n/d)
+ */
+double avmd_desa2_tweaked(circ_buffer_t *b, size_t i,
+                            switch_core_session_t *session);
+
+
+#endif  /* __AVMD_DESA2_TWEAKED_H__ */

src/mod/applications/mod_avmd/avmd_fast_acosf.h

-#ifndef __FAST_ACOSF_H__
-#define __FAST_ACOSF_H__
+/*
+ * @brief   Fast arithmetic using precomputed arc cosine table.
+ * @author  Eric des Courtis
+ * @par     Modifications: Piotr Gregor < piotrek.gregor gmail.com >
+ */
+
+
+#ifndef __AVMD_FAST_ACOSF_H__
+#define __AVMD_FAST_ACOSF_H__
 
 
 #define ACOS_TABLE_FILENAME "/tmp/acos_table.dat"
 
+
 /*! \brief Arc cosine table initialization.
  *
  * @author Eric des Courtis
@@ -42,5 +50,4 @@ extern float fast_acosf(float x);
  */
 extern int compute_table(void);
 
-#endif
-
+#endif /* __AVMD_FAST_ACOSF_H__ */

src/mod/applications/mod_avmd/avmd_fir.h

+/*
+ * @brief   Filters.
+ * @author  Piotr Gregor < piotrek.gregor gmail.com >
+ * @date    23 Mar 2016
+ */
+
+
+#ifndef __AVMD_FIR_H__
+#define __AVMD_FIR_H__
+
+
+#define DESA_MAX(a, b) (a) > (b) ? (a) : (b)
+#define MEDIAN_FILTER(a, b, c) (a) > (b) ? ((a) > (c) ? \
+                DESA_MAX((b), (c)) : a) : ((b) > (c) ? DESA_MAX((a), (c)) : (b))
+
+
+#endif

src/mod/applications/mod_avmd/avmd_goertzel.c

-#ifndef __GOERTZEL_H__
+#ifndef __AVMD_GOERTZEL_H__
+
+
 #include <math.h>
 #include "avmd_goertzel.h"
 #include "avmd_buffer.h"
 
-/*! \brief Identify frequency components of a signal
- * @author Eric des Courtis
- * @param b A circular buffer
- * @param pos Position in the buffer
- * @param f Frequency to look at
- * @param num Number of samples to look at
- * @return A power estimate for frequency f at position pos in the stream
- */
-extern double goertzel(circ_buffer_t *b, size_t pos, double f, size_t num)
+
+extern double avmd_goertzel(circ_buffer_t *b, size_t pos, double f, size_t num)
 {
     double s = 0.0;
     double p = 0.0;
@@ -22,15 +17,14 @@ extern double goertzel(circ_buffer_t *b, size_t pos, double f, size_t num)
     coeff = 2.0 * cos(2.0 * M_PI * f);
 
     for (i = 0; i < num; i++) {
-	    /* TODO: optimize to avoid GET_SAMPLE when possible */
-	    s = GET_SAMPLE(b, i + pos) + (coeff * p) - p2;
-	    p2 = p;
-	    p = s;
+        /* TODO: optimize to avoid GET_SAMPLE when possible */
+        s = GET_SAMPLE(b, i + pos) + (coeff * p) - p2;
+        p2 = p;
+        p = s;
     }
 
     return (p2 * p2) + (p * p) - (coeff * p2 * p);
 }
 
 
-#endif
-
+#endif /* __AVMD_GOERTZEL_H__ */

src/mod/applications/mod_avmd/avmd_goertzel.h

-#ifndef __GOERTZEL_H__
-#define __GOERTZEL_H__
+/*
+ * @brief   Goertzel algorithm.
+ * @author  Eric des Courtis
+ */
+
+
+#ifndef __AVMD_GOERTZEL_H__
+#define __AVMD_GOERTZEL_H__
+
 
 #ifndef _MSC_VER
 #include <stdint.h>
@@ -11,8 +18,16 @@
 #define M_PI 3.14159265358979323846264338327
 #endif
 
-extern double goertzel(circ_buffer_t *b, size_t pos, double f, size_t num);
 
-#endif
+/*! \brief Identify frequency components of a signal
+ * @author Eric des Courtis
+ * @param b A circular buffer
+ * @param pos Position in the buffer
+ * @param f Frequency to look at
+ * @param num Number of samples to look at
+ * @return A power estimate for frequency f at position pos in the stream
+ */
+extern double avmd_goertzel(circ_buffer_t *b, size_t pos, double f, size_t num);
 
 
+#endif /* __AVMD_GOERTZEL_H__ */

src/mod/applications/mod_avmd/avmd_options.h

@@ -10,11 +10,13 @@
 #define __AVMD_OPTIONS_H__
 
 
-/* #define AVMD_DEBUG 1 */
+/* define/undefine this to enable/disable printing of avmd
+ * intermediate computations to log */
+/*#define AVMD_DEBUG */
 
 /* define/undef this to enable/disable reporting of beep
  * detection status after session ended */
-#define AVMD_REPORT_STATUS 1
+#define AVMD_REPORT_STATUS
 
 /* define/undefine this to enable/disable faster computation
  * of arcus cosine - table will be created mapping floats
@@ -25,7 +27,16 @@
 /* define/undefine this to classify avmd beep detection as valid
  * only when there is required number of consecutive elements
  * in the SMA buffer without reset */
-#define AVMD_REQUIRE_CONTINUOUS_STREAK 5
+#define AVMD_REQUIRE_CONTINUOUS_STREAK
+
+/* define number of samples to skip starting from the beginning
+ *  of frame and after reset */
+#define AVMD_SAMLPE_TO_SKIP_N 6
+
+/* define/undefine this to enable/disable simplified estimation
+ * of frequency based on approximation of sin(x) with (x)
+ * in the range x=[0,PI/2] */
+#define AVMD_SIMPLIFIED_ESTIMATION
 
 /* define/undefine to enable/disable avmd on incoming audio */
 #define AVMD_INBOUND_CHANNEL

src/mod/applications/mod_avmd/avmd_psi.h

-#ifndef __PSI_H__
-#define __PSI_H__
-#include "avmd_buffer.h"
+#ifndef __AVMD_PSI_H__
+#define __AVMD_PSI_H__
 
-#define PSI(b, i) (GET_SAMPLE((b), ((i) + 1))*GET_SAMPLE((b), ((i) + 1))-GET_SAMPLE((b), ((i) + 2))*GET_SAMPLE((b), ((i) + 0)))
 
-#endif
+#include "avmd_buffer.h"
 
+#define PSI(b, i) (GET_SAMPLE((b), ((i) + 1))*GET_SAMPLE((b), ((i) + 1))-GET_SAMPLE((b), ((i) + 2))*GET_SAMPLE((b), ((i) + 0)))
 
+#endif /* __AVMD_PSI_H__ */

src/mod/applications/mod_avmd/avmd_sma_buf.h

-#ifndef __SMA_BUFFER_H__
-#define __SMA_BUFFER_H__
+/*
+ * @brief   SMA buffer.
+ *
+ * @author Eric des Courtis
+ * @par    Modifications: Piotr Gregor < piotrek.gregor gmail.com >
+ */
+
+
+#ifndef __AVMD_SMA_BUFFER_H__
+#define __AVMD_SMA_BUFFER_H__
+
+
 #include <stdio.h>
 #include <stdlib.h>
 #ifndef _MSC_VER
@@ -64,7 +74,11 @@ typedef struct {
     }while(0);
 
 */
-#endif
+
+
+#endif /* __AVMD_SMA_BUFFER_H__ */
+
+
 /*
 
 int main(void)

src/mod/applications/mod_avmd/mod_avmd.2015.vcxproj

@@ -154,4 +154,4 @@
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
   <ImportGroup Label="ExtensionTargets">
   </ImportGroup>
-</Project>
+</Project>
\ No newline at end of file