Fix the M17 convolution.

Author: g4klx

M17Control.cpp

@@ -258,29 +258,12 @@ bool CM17Control::writeModem(unsigned char* data, unsigned int len)
 		unsigned char frame[M17_FN_LENGTH_BYTES + M17_PAYLOAD_LENGTH_BYTES];
 		unsigned int errors = conv.decodeData(data + 2U + M17_SYNC_LENGTH_BYTES + M17_LICH_FRAGMENT_FEC_LENGTH_BYTES, frame);
 
-		// If we have a BER of less than 12, then we consider the audio to be usable
-		bool valid = errors < 12U;
-
-		if (!valid) {
-			m_rfFN++;
-
-			frame[0U] = (m_rfFN >> 8) & 0xFFU;
-			frame[1U] = (m_rfFN >> 0) & 0xFFU;
-
-			if (m_rfState == RS_RF_AUDIO) {
-				::memcpy(frame + 2U + 0U, M17_3200_SILENCE, 8U);
-				::memcpy(frame + 2U + 8U, M17_3200_SILENCE, 8U);
-			} else {
-				::memcpy(frame + 2U + 0U, M17_1600_SILENCE, 4U);
-				::memcpy(frame + 2U + 4U, M17_1600_SILENCE, 4U);
-				::memset(frame + 2U + 8U, 0x00U, 8U);
-			}
-		} else {
-			m_rfFN = (frame[0U] << 8) + (frame[1U] << 0);
-		}
+		m_rfFN = (frame[0U] << 8) + (frame[1U] << 0);
 
 		LogDebug("M17, audio: FN: %u, errs: %u/272 (%.1f%%)", m_rfFN & 0x7FFFU, errors, float(errors) / 2.72F);
 
+		m_rfFN++;
+
 		m_rfBits += 272U;
 		m_rfErrs += errors;
 
@@ -343,7 +326,7 @@ bool CM17Control::writeModem(unsigned char* data, unsigned int len)
 			m_rfLSFn = 0U;
 
 		// Only check for the EOT marker if the frame has a reasonable BER
-		if (valid && ((m_rfFN & 0x8000U) == 0x8000U)) {
+		if ((m_rfFN & 0x8000U) == 0x8000U) {
 			std::string source = m_rfLSF.getSource();
 			std::string dest   = m_rfLSF.getDest();
 

M17Convolution.cpp

@@ -33,7 +33,7 @@ const unsigned int PUNCTURE_LIST_LINK_SETUP[] = {
 	362U, 369U, 372U, 375U, 378U, 385U, 388U, 391U, 394U, 401U, 404U, 407U, 410U, 417U, 420U, 423U, 430U, 433U, 436U, 439U, 446U,
 	449U, 452U, 455U, 462U, 465U, 468U, 471U, 478U, 481U, 484U};
 
-const unsigned int PUNCTURE_LIST_DATA_COUNT = 22U;
+const unsigned int PUNCTURE_LIST_DATA_COUNT = 12U;
 
 const unsigned int PUNCTURE_LIST_DATA[] = {
 	11U, 23U, 35U, 47U, 59U, 71U, 83U, 95U, 107U, 119U, 131U, 143U, 155U, 167U, 179U, 191U, 203U, 215U, 227U, 239U, 251U, 263U,
@@ -128,6 +128,7 @@ unsigned int CM17Convolution::decodeLinkSetup(const unsigned char* in, unsigned
 	assert(out != NULL);
 
 	uint8_t temp[500U];
+	::memset(temp, 0x00U, 500U);
 
 	unsigned int n = 0U;
 	unsigned int index = 0U;
@@ -141,9 +142,6 @@ unsigned int CM17Convolution::decodeLinkSetup(const unsigned char* in, unsigned
 		temp[n++] = b ? 2U : 0U;
 	}
 
-	for (unsigned int i = 0U; i < 8U; i++)
-		temp[n++] = 0U;
-
 	start();
 
 	n = 0U;
@@ -154,15 +152,16 @@ unsigned int CM17Convolution::decodeLinkSetup(const unsigned char* in, unsigned
 		decode(s0, s1);
 	}
 
-	return chainback(out, 144U) - PUNCTURE_LIST_LINK_SETUP_COUNT;
+	return chainback(out, 240U) - PUNCTURE_LIST_LINK_SETUP_COUNT;
 }
 
 unsigned int CM17Convolution::decodeData(const unsigned char* in, unsigned char* out)
 {
 	assert(in != NULL);
 	assert(out != NULL);
 
-	uint8_t temp[350U];
+	uint8_t temp[300U];
+	::memset(temp, 0x00U, 300U);
 
 	unsigned int n = 0U;
 	unsigned int index = 0U;
@@ -176,20 +175,17 @@ unsigned int CM17Convolution::decodeData(const unsigned char* in, unsigned char*
 		temp[n++] = b ? 2U : 0U;
 	}
 
-	for (unsigned int i = 0U; i < 8U; i++)
-		temp[n++] = 0U;
-
 	start();
 
 	n = 0U;
-	for (unsigned int i = 0U; i < 164U; i++) {
+	for (unsigned int i = 0U; i < 148U; i++) {
 		uint8_t s0 = temp[n++];
 		uint8_t s1 = temp[n++];
 
 		decode(s0, s1);
 	}
 
-	return chainback(out, 160U) - PUNCTURE_LIST_DATA_COUNT;
+	return chainback(out, 144U) - PUNCTURE_LIST_DATA_COUNT;
 }
 
 void CM17Convolution::start()

Version.h

@@ -19,6 +19,6 @@
 #if !defined(VERSION_H)
 #define	VERSION_H
 
-const char* VERSION = "20210810";
+const char* VERSION = "20210811";
 
 #endif