DSTAR Single Frequency Tone Support;

CHANGELOG

@@ -1,8 +1,11 @@
+1.3.4: 
+	Add Single Frequency Tone support for DSTAR AMBE based on previous code writers guesswork
+
 1.3.3T:
 	Add AMBE+2 tones (adapted from Boatbod OP25)
 
-	1.3.2: 
-	Disable/Remove Tests
+1.3.2: 
+Disable/Remove Tests
 
 1.3.1:
 	Redirect all printf to stderr (	Change all printf to fprintf(stderr,) )

README.md

@@ -9,7 +9,7 @@ Readers are strongly advised to check for any patent restrictions
 or licencing requirements before compiling or using this source code.
 ```
 
-mbelib 1.3.3T w/ AMBE+2 Tone Synthesis
+mbelib 1.3.4 w/ AMBE and AMBE+2 Tone Synthesis
 
 ```
 mbelib supports the 7200x4400 bit/s codec used in P25 Phase 1,
@@ -30,4 +30,4 @@ make
 sudo make install
 ```
 
-To Disable AMBE+2 Tones, run cmake with option `cmake -DNOTONES=ON ..` when building.
+To Disable AMBE and AMBE+2 Tones, run cmake with option `cmake -DNOTONES=ON ..` when building.

ambe3600x2400.c

@@ -213,29 +213,30 @@ mbe_decodeAmbe2400Parms (char *ambe_d, mbe_parms * cur_mp, mbe_parms * prev_mp)
     b2 |= ambe_d[17];      //v0 1   a guess based on data
     // the order of the last 3 bits may really be 17,44,45 not 44,45,17 as above
 
-    fprintf(stderr,"Tone volume: %d; ", b2);
+    // fprintf(stderr,"Tone volume: %d; ", b2);
     if (b1 < 5)
     {
-      fprintf(stderr, "index: %d, was <5, invalid!\n", b1);
+      // fprintf(stderr, "index: %d, was <5, invalid!\n", b1);
       silence = 1;
     }
     else if ((b1 >= 5) && (b1 <= 122))
     {
-      fprintf(stderr, "index: %d, Single tone hz: %f\n", b1, (float)b1*31.25);
+      // fprintf(stderr, "index: %d, Single tone hz: %f\n", b1, (float)b1*31.25);
+      return (b1); //use the return value to play a single frquency valid tone
     }
     else if ((b1 > 122) && (b1 < 128))
     {
-      fprintf(stderr, "index: %d, was >122 and <128, invalid!\n", b1);
+      // fprintf(stderr, "index: %d, was >122 and <128, invalid!\n", b1);
       silence = 1;
     }
     else if ((b1 >= 128) && (b1 <= 163))
     {
-      fprintf(stderr, "index: %d, Dual tone\n", b1);
+      // fprintf(stderr, "index: %d, Dual tone\n", b1);
 	  // note: dual tone index is different on ambe(dstar) and ambe2+
     }
     else
     {
-      fprintf(stderr, "index: %d, was >163, invalid!\n", b1);
+      // fprintf(stderr, "index: %d, was >163, invalid!\n", b1);
       silence = 1;
     }
 
@@ -677,6 +678,13 @@ mbe_processAmbe2400Dataf (float *aout_buf, int *errs, int *errs2, char *err_str,
       err_str++;
       cur_mp->repeat = 0;
     }
+  //if we have a 'seemingly' valid single frequency tone and errors are within margin
+  else if ( (bad >= 7) && (bad <= 122) && (*errs < 2) && (*errs2 < 3)) //&& (*errs < 2) && (*errs2 < 3)
+  {
+    //synthesize single frequency tone based on previous code writers guessword, 'bad' is the tone ID value
+    mbe_synthesizeTonefdstar (aout_buf, ambe_d, cur_mp, bad);
+    mbe_moveMbeParms (cur_mp, prev_mp);
+  }
   else if (*errs2 > 3)
     {
       mbe_useLastMbeParms (cur_mp, prev_mp);

libmbe.pc.in

@@ -3,7 +3,7 @@ includedir=@CMAKE_INSTALL_FULL_INCLUDEDIR@
 
 Name: libMBE
 Description: AMBE and IMBE vocoder
-Version: 1.3.3T
+Version: 1.3.4
 
 Libs: -L${libdir} -lmbe
 Libs.private: -lm

mbelib.c

@@ -385,6 +385,64 @@ void mbe_synthesizeTonef (float *aout_buf, char *ambe_d, mbe_parms * cur_mp)
     }
     return;
   }
+
+  //debug
+  // fprintf (stderr, "TONE ID = %d AD = %d \n", ID1, AD);
+
+  // Synthesize tones
+  step1 = 2 * M_PI * freq1 / 8000.0f;
+  step2 = 2 * M_PI * freq2 / 8000.0f;
+  amplitude = AD * 75.0f; //
+  aout_buf_p = aout_buf;
+  for (n = 0; n < 160; n++)
+  {
+    *aout_buf_p = (float) ( amplitude * (sin((cur_mp->swn) * step1)/2 + sin((cur_mp->swn) * step2)/2) );
+    *aout_buf_p = *aout_buf_p / 6.0f;
+    aout_buf_p++;
+    cur_mp->swn++;
+  }
+}
+
+//simplified version for single frequency dstar based on previous code writers guessword
+void mbe_synthesizeTonefdstar (float *aout_buf, char *ambe_d, mbe_parms * cur_mp, int ID1)
+{
+  int i, n;
+  float *aout_buf_p;
+
+  int AD = 103; //amplitude, just using a value I've seen in other tones
+  float step1, step2, sample, amplitude;
+  float freq1 = 0, freq2 = 0;
+
+  #ifdef DISABLE_AMBE_TONES //generate silence if tones disabled
+  aout_buf_p = aout_buf;
+  for (n = 0; n < 160; n++)
+  {
+    *aout_buf_p = (float) 0;
+    aout_buf_p++;
+  }
+  return;
+  #endif
+
+  switch(ID1)
+  {
+    // single tones, set frequency
+    case 5:
+        freq1 = 156.25; freq2 = freq1;
+        break;
+    case 6:
+        freq1 = 187.5; freq2 = freq1;
+        break;
+    // single tones, calculated frequency
+    default:
+        if ((ID1 >= 7) && (ID1 <= 122))
+        {
+          freq1 = 31.25 * ID1; freq2 = freq1;
+        }
+  }
+
+  //debug
+  // fprintf (stderr, "TONE ID = %d AD = %d \n", ID1, AD);
+
   // Synthesize tones
   step1 = 2 * M_PI * freq1 / 8000.0f;
   step2 = 2 * M_PI * freq2 / 8000.0f;

mbelib.h

@@ -17,7 +17,7 @@
 
 #ifndef _MBELIB_H
 #define _MBELIB_H
-#define MBELIB_VERSION "1.3.3T"
+#define MBELIB_VERSION "1.3.4"
 
 struct mbe_parameters
 {
@@ -105,6 +105,7 @@ void mbe_useLastMbeParms (mbe_parms * cur_mp, mbe_parms * prev_mp);
 void mbe_initMbeParms (mbe_parms * cur_mp, mbe_parms * prev_mp, mbe_parms * prev_mp_enhanced);
 void mbe_spectralAmpEnhance (mbe_parms * cur_mp);
 void mbe_synthesizeTonef (float *aout_buf, char *ambe_d, mbe_parms * cur_mp);
+void mbe_synthesizeTonefdstar (float *aout_buf, char *ambe_d, mbe_parms * cur_mp, int ID1);
 void mbe_synthesizeSilencef (float *aout_buf);
 void mbe_synthesizeSilence (short *aout_buf);
 void mbe_synthesizeSpeechf (float *aout_buf, mbe_parms * cur_mp, mbe_parms * prev_mp, int uvquality);