implement support for a silence threshold in DMR (this will help null highly degraded audio to prevent horrifying ear destroying screeching); some minor code cleanup (mostly removing magic numbers!);

config.yml

@@ -41,6 +41,7 @@ protocols:
         dumpCsbkData: false
         callHang: 5
         txHang: 8
+        silenceThreshold: 21
         queueSize: 5000
         verbose: true
         debug: false
@@ -92,7 +93,7 @@ system:
         dmrNetId: 1
         voiceChNo:
             - 1
-        colorCode: 5
+        colorCode: 1
         nac: 293
         pSuperGroup: FFFF
         netId: BB800

dmr/Control.cpp

@@ -136,12 +136,22 @@ void Control::setOptions(yaml::Node& conf, uint32_t netId, uint8_t siteId, uint8
         m_slot2->setTSCC(enableTSCC, dedicatedTSCC);
         break;
     default:
-        LogError(LOG_NET, "DMR, invalid slot, TSCC disabled, slotNo = %u", m_tsccSlotNo);
+        LogError(LOG_DMR, "DMR, invalid slot, TSCC disabled, slotNo = %u", m_tsccSlotNo);
         break;
     }
 
+    uint32_t silenceThreshold = dmrProtocol["silenceThreshold"].as<uint32_t>(dmr::DEFAULT_SILENCE_THRESHOLD);
+    if (silenceThreshold > MAX_DMR_VOICE_ERRORS) {
+        LogWarning(LOG_DMR, "Silence threshold > %u, defaulting to %u", dmr::MAX_DMR_VOICE_ERRORS, dmr::DEFAULT_SILENCE_THRESHOLD);
+        silenceThreshold = dmr::DEFAULT_SILENCE_THRESHOLD;
+    }
+
+    m_slot1->setSilenceThreshold(silenceThreshold);
+    m_slot2->setSilenceThreshold(silenceThreshold);
+
     if (printOptions) {
         LogInfo("    TSCC Slot: %u", m_tsccSlotNo);
+        LogInfo("    Silence Threshold: %u (%.1f%%)", silenceThreshold, float(silenceThreshold) / 1.41F);
     }
 }
 

dmr/DMRDefines.h

@@ -99,6 +99,8 @@ namespace dmr
         0x81U, 0x52U, 0x60U, 0x00U, 0x00U, 0x00U, 0x00U, 0x00U, 0x01U, 0x73U, 0x00U,
         0x2AU, 0x6BU, 0xB9U, 0xE8U, 0x81U, 0x52U, 0x61U, 0x73U, 0x00U, 0x2AU, 0x6BU };
 
+    const uint8_t   DMR_NULL_AMBE[] = { 0xB1U, 0xA8U, 0x22U, 0x25U, 0x6BU, 0xD1U, 0x6CU, 0xCFU, 0x67U };
+
     const uint8_t   PAYLOAD_LEFT_MASK[] = { 0xFFU, 0xFFU, 0xFFU, 0xFFU, 0xFFU, 0xFFU, 0xFFU, 0xFFU, 0xFFU, 0xFFU, 0xFFU, 0xFFU, 0xFFU, 0xF0U };
     const uint8_t   PAYLOAD_RIGHT_MASK[] = { 0x0FU, 0xFFU, 0xFFU, 0xFFU, 0xFFU, 0xFFU, 0xFFU, 0xFFU, 0xFFU, 0xFFU, 0xFFU, 0xFFU, 0xFFU, 0xFFU };
 
@@ -130,6 +132,9 @@ namespace dmr
     
     const uint16_t  DMR_LOGICAL_CH_ABSOLUTE = 0xFFFU;
 
+    const uint32_t  DEFAULT_SILENCE_THRESHOLD = 21U;
+    const uint32_t  MAX_DMR_VOICE_ERRORS = 141U;
+
     // PDU Data Formats
     const uint8_t   DPF_UDT = 0x00U;
     const uint8_t   DPF_RESPONSE = 0x01U;

dmr/Slot.cpp

@@ -142,6 +142,7 @@ Slot::Slot(uint32_t slotNo, uint32_t timeout, uint32_t tgHang, uint32_t queueSiz
     m_minRSSI(0U),
     m_aveRSSI(0U),
     m_rssiCount(0U),
+    m_silenceThreshold(DEFAULT_SILENCE_THRESHOLD),
     m_ccSeq(0U),
     m_ccRunning(false),
     m_enableTSCC(false),
@@ -525,6 +526,15 @@ void Slot::setTSCC(bool enable, bool dedicated)
     m_dedicatedTSCC = dedicated;
 }
 
+/// <summary>
+/// Helper to set the voice error silence threshold.
+/// </summary>
+/// <param name="threshold"></param>
+void Slot::setSilenceThreshold(uint32_t threshold)
+{
+    m_silenceThreshold = threshold;
+}
+
 /// <summary>
 /// Helper to initialize the DMR slot processor.
 /// </summary>

dmr/Slot.h

@@ -93,6 +93,8 @@ namespace dmr
 
         /// <summary>Helper to enable and configure TSCC support for this slot.</summary>
         void setTSCC(bool enable, bool dedicated);
+        /// <summary>Helper to set the voice error silence threshold.</summary>
+        void setSilenceThreshold(uint32_t threshold);
 
         /// <summary>Helper to initialize the slot processor.</summary>
         static void init(uint32_t colorCode, SiteData siteData, bool embeddedLCOnly, bool dumpTAData, uint32_t callHang, modem::Modem* modem,
@@ -156,6 +158,8 @@ namespace dmr
         uint32_t m_aveRSSI;
         uint32_t m_rssiCount;
 
+        uint32_t m_silenceThreshold;
+
         uint8_t m_ccSeq;
         bool m_ccRunning;
 

dmr/VoicePacket.cpp

@@ -259,6 +259,13 @@ bool VoicePacket::process(uint8_t* data, uint32_t len)
                         errors, float(errors) / 1.41F);
                 }
 
+                if (errors > m_slot->m_silenceThreshold) {
+                    insertNullAudio(data + 2U);
+                    m_fec.regenerateDMR(data + 2U);
+
+                    LogWarning(LOG_RF, DMR_DT_VOICE_SYNC ", exceeded lost audio threshold, filling in");
+                }
+
                 m_slot->m_rfErrs += errors;
             }
 
@@ -312,6 +319,20 @@ bool VoicePacket::process(uint8_t* data, uint32_t len)
                         m_rfN, errors, float(errors) / 1.41F);
                 }
 
+                if (errors > m_slot->m_silenceThreshold) {
+                    // Get the LCSS from the EMB
+                    data::EMB emb;
+                    emb.decode(data + 2U);
+
+                    insertNullAudio(data + 2U);
+                    m_fec.regenerateDMR(data + 2U);
+
+                    // Regenerate EMB
+                    emb.encode(data + 2U);
+
+                    LogWarning(LOG_RF, DMR_DT_VOICE ", exceeded lost audio threshold, filling in");
+                }
+
                 m_slot->m_rfErrs += errors;
             }
 
@@ -540,10 +561,24 @@ bool VoicePacket::process(uint8_t* data, uint32_t len)
                 if (fid == FID_ETSI || fid == FID_DMRA) {
                     errors = m_fec.regenerateDMR(data + 2U);
                     if (m_verbose) {
-                        LogMessage(LOG_RF, "DMR Slot %u, DT_VOICE audio, sequence no = %u, errs = %u/141 (%.1f%%)",
+                        LogMessage(LOG_RF, DMR_DT_VOICE ", audio, slot = %u, sequence no = %u, errs = %u/141 (%.1f%%)",
                             m_slot->m_slotNo, m_rfN, errors, float(errors) / 1.41F);
                     }
 
+                    if (errors > m_slot->m_silenceThreshold) {
+                        // Get the LCSS from the EMB
+                        data::EMB emb;
+                        emb.decode(data + 2U);
+
+                        insertNullAudio(data + 2U);
+                        m_fec.regenerateDMR(data + 2U);
+
+                        // Regenerate EMB
+                        emb.encode(data + 2U);
+
+                        LogWarning(LOG_RF, DMR_DT_VOICE ", exceeded lost audio threshold, filling in");
+                    }
+
                     m_slot->m_rfErrs += errors;
                 }
 
@@ -1121,6 +1156,27 @@ void VoicePacket::logGPSPosition(const uint32_t srcId, const uint8_t* data)
     LogMessage(LOG_DMR, "GPS position for %u [lat %f, long %f] (Position error %s)", srcId, latitude, longitude, error);
 }
 
+/// <summary>
+/// Helper to insert AMBE null frames for missing audio.
+/// </summary>
+/// <param name="data"></param>
+void VoicePacket::insertNullAudio(uint8_t* data)
+{
+    uint8_t* ambeBuffer = new uint8_t[dmr::DMR_AMBE_LENGTH_BYTES];
+    ::memset(ambeBuffer, 0x00U, dmr::DMR_AMBE_LENGTH_BYTES);
+
+    for (uint32_t i = 0; i < 3U; i++) {
+        ::memcpy(ambeBuffer + (i * 9U), DMR_NULL_AMBE, 9U);
+    }
+
+    ::memcpy(data, ambeBuffer, 13U);
+    data[13U] = ambeBuffer[13U] & 0xF0U;
+    data[19U] = ambeBuffer[13U] & 0x0FU;
+    ::memcpy(data + 20U, ambeBuffer + 14U, 13U);
+
+    delete[] ambeBuffer;
+}
+
 /// <summary>
 /// Helper to insert DMR AMBE silence frames.
 /// </summary>

dmr/VoicePacket.h

@@ -105,6 +105,8 @@ namespace dmr
         /// <summary></summary>
         void logGPSPosition(const uint32_t srcId, const uint8_t* data);
 
+        /// <summary>Helper to insert AMBE null frames for missing audio.</summary>
+        void insertNullAudio(uint8_t* data);
         /// <summary>Helper to insert DMR AMBE silence frames.</summary>
         bool insertSilence(const uint8_t* data, uint8_t seqNo);
         /// <summary>Helper to insert DMR AMBE silence frames.</summary>

p25/Control.cpp

@@ -214,6 +214,10 @@ void Control::setOptions(yaml::Node& conf, const std::string cwCallsign, const s
     m_ackTSBKRequests = control["ackRequests"].as<bool>(true);
 
     m_voice->m_silenceThreshold = p25Protocol["silenceThreshold"].as<uint32_t>(p25::DEFAULT_SILENCE_THRESHOLD);
+    if (m_voice->m_silenceThreshold > MAX_P25_VOICE_ERRORS) {
+        LogWarning(LOG_P25, "Silence threshold > %u, defaulting to %u", p25::MAX_P25_VOICE_ERRORS, p25::DEFAULT_SILENCE_THRESHOLD);
+        m_voice->m_silenceThreshold = p25::DEFAULT_SILENCE_THRESHOLD;
+    }
 
     m_disableNetworkHDU = p25Protocol["disableNetworkHDU"].as<bool>(false);
 

p25/P25Defines.h

@@ -202,6 +202,7 @@ namespace p25
     const uint32_t  P25_TGID_ALL = 0xFFFFU;
 
     const uint32_t  DEFAULT_SILENCE_THRESHOLD = 124U;
+    const uint32_t  MAX_P25_VOICE_ERRORS = 1233U;
 
     // PDU Format Type(s)
     const uint8_t   PDU_FMT_RSP = 0x03U;

p25/VoicePacket.cpp

@@ -889,7 +889,7 @@ VoicePacket::VoicePacket(Control* p25, network::BaseNetwork* network, bool debug
     m_hadVoice(false),
     m_lastRejectId(0U),
     m_lastPatchGroup(0U),
-    m_silenceThreshold(124U),
+    m_silenceThreshold(DEFAULT_SILENCE_THRESHOLD),
     m_vocLDU1Count(0U),
     m_verbose(verbose),
     m_debug(debug)