libsample: Add another function for converting between int16_t and sample_t

Now we have speech level and 1mW (0 dBm) conversion functions

src/eurosignal/eurosignal.c

@@ -506,7 +506,7 @@ static void call_play_announcement(euro_call_t *call)
 		else
 			chunk[i] = 0.0;
 	}
-	int16_to_samples(spl, chunk, 160);
+	int16_to_samples_speech(spl, chunk, 160);
 	call_up_audio(call->callref, spl, 160);
 }
 

src/libmobile/call.c

@@ -395,7 +395,7 @@ void down_audio(struct osmo_cc_session_codec *codec, uint16_t sequence_number, u
 	/* if we are disconnected, ignore audio */
 	if (!process || process->pattern != PATTERN_NONE)
 		return;
-	int16_to_samples(samples, (int16_t *)data, len / 2);
+	int16_to_samples_speech(samples, (int16_t *)data, len / 2);
 #ifdef DEBUG_LEVEL
 	double lev = level_of(samples, len / 2);
 	printf("festnetz-level: %s                  %.4f\n", debug_db(lev), (20 * log10(lev)));
@@ -621,7 +621,7 @@ void call_up_audio(int callref, sample_t *samples, int count)
 	double lev = level_of(samples, count);
 	printf("   mobil-level: %s%.4f\n", debug_db(lev), (20 * log10(lev)));
 #endif
-	samples_to_int16(data, samples, count);
+	samples_to_int16_speech(data, samples, count);
 	osmo_cc_rtp_send(process->codec, (uint8_t *)data, count * 2, 1, count);
 	/* don't destroy process here in case of an error */
 }

src/libmobile/console.c

@@ -148,7 +148,7 @@ void up_audio(struct osmo_cc_session_codec *codec, uint16_t sequence_number, uin
 
 	/* save audio from transceiver to jitter buffer */
 	if (console.sound) {
-		int16_to_samples(samples, (int16_t *)data, count);
+		int16_to_samples_speech(samples, (int16_t *)data, count);
 		jitter_save(&console.dejitter, samples, count, 1, sequence_number, timestamp, ssrc);
 		return;
 	}
@@ -627,7 +627,7 @@ void process_console(int c)
 				/* only if we have a call */
 				if (console.callref && console.codec) {
 					int16_t data[160];
-					samples_to_int16(data, console.tx_buffer, 160);
+					samples_to_int16_speech(data, console.tx_buffer, 160);
 					osmo_cc_rtp_send(console.codec, (uint8_t *)data, 160 * 2, 1, 160);
 				}
 			}

src/libsample/sample.c

@@ -25,6 +25,7 @@
  * of 16 bits signed value:
  */
 static double int_16_speech_level = SPEECH_LEVEL * 0.7079; /* 16 dBm below dBm0, which is about 3dBm below full 16 bit range */
+static double int_16_1mw_level = 0.7079; /* dBm0, 3dBm below full 16 bit range */
 
 /* A sample_t is a value that has virtually infinite precision but will also
  * support high numbers. 'double' or 'float' types are sufficient.
@@ -40,7 +41,8 @@ static double int_16_speech_level = SPEECH_LEVEL * 0.7079; /* 16 dBm below dBm0,
  * envelope is network dependent.
  */
 
-void samples_to_int16(int16_t *spl, sample_t *samples, int length)
+/* sample conversion relative to SPEECH level */
+void samples_to_int16_speech(int16_t *spl, sample_t *samples, int length)
 {
 	int32_t value;
 
@@ -55,10 +57,33 @@ void samples_to_int16(int16_t *spl, sample_t *samples, int length)
 	}
 }
 
-void int16_to_samples(sample_t *samples, int16_t *spl, int length)
+void int16_to_samples_speech(sample_t *samples, int16_t *spl, int length)
 {
 	while (length--) {
 		*samples++ = (double)(*spl++) / 32767.0 / int_16_speech_level;
 	}
 }
 
+/* sample conversion relative to 1mW level */
+void samples_to_int16_1mw(int16_t *spl, sample_t *samples, int length)
+{
+	int32_t value;
+
+	while (length--) {
+		value = *samples++ * int_16_1mw_level * 32768.0;
+		if (value > 32767.0)
+			*spl++ = 32767;
+		else if (value < -32767.0)
+			*spl++ = -32767;
+		else
+			*spl++ = (uint16_t)value;
+	}
+}
+
+void int16_to_samples_1mw(sample_t *samples, int16_t *spl, int length)
+{
+	while (length--) {
+		*samples++ = (double)(*spl++) / 32767.0 / int_16_1mw_level;
+	}
+}
+

src/libsample/sample.h

@@ -3,6 +3,8 @@ typedef double sample_t;
 
 #define	SPEECH_LEVEL	0.1585
 
-void samples_to_int16(int16_t *spl, sample_t *samples, int length);
-void int16_to_samples(sample_t *samples, int16_t *spl, int length);
+void samples_to_int16_speech(int16_t *spl, sample_t *samples, int length);
+void int16_to_samples_speech(sample_t *samples, int16_t *spl, int length);
+void samples_to_int16_1mw(int16_t *spl, sample_t *samples, int length);
+void int16_to_samples_1mw(sample_t *samples, int16_t *spl, int length);
 

src/zeitansage/zeitansage.c

@@ -296,7 +296,7 @@ next_sample:
 	call->spl_time = spl_time;
 
 	/* convert to samples, apply gain and send toward fixed network */
-	int16_to_samples(spl, chunk, 160);
+	int16_to_samples_speech(spl, chunk, 160);
 	for (i = 0; i < 160; i++)
 		spl[i] *= audio_gain;
 	call_up_audio(call->callref, spl, 160);