feat(dmr): decode and route AMBE voice

DMRDecoder.pas

@@ -27,8 +27,11 @@ const
   DMR_RING_SIZE        = 65536; // >1.3 s at 48 kHz, power of two
   DMR_BURST_DIBITS     = 144;
   DMR_SYNC_END_DIBIT   = 89;    // sync occupies burst dibits 66..89
+  DMR_VOICE_FRAME_SAMPLES = DMR_PCM_SAMPLES; // 20 ms at 8 kHz
 
 type
+  TDMRAudioEvent = procedure(const PCM: array of Single; Count: Integer) of object;
+
   TDMRSyncKind = (
     dskNone,
     dskBSData, dskBSVoice,
@@ -62,6 +65,9 @@ type
     ServiceOptions: Integer;
     TargetID: LongWord;
     SourceID: LongWord;
+    SelectedSlot: Integer;
+    VoiceFrameCount: QWord;
+    VoiceErrorCount: QWord;
   end;
 
   TDMRDecoder = class;
@@ -111,6 +117,9 @@ type
     FLastLCSlot: Integer;
     FColorCodeValid: Boolean;
     FColorCode, FLastDataType, FSlotTypeCorrectedBits: Integer;
+    FSelectedSlot: Integer;
+    FVoiceFrameCount, FVoiceErrorCount: QWord;
+    FOnAudio: TDMRAudioEvent;
     FBurstCount: QWord;
     FRMSSq: Double;
 
@@ -127,6 +136,7 @@ type
     function Digitize(Phase: Integer; Symbol: Double): Byte;
     procedure StartBurstTracking(Phase: Integer);
     procedure CompleteBurst;
+    procedure DecodeVoiceBurst;
     procedure ResetDSP;
   public
     constructor Create;
@@ -140,6 +150,7 @@ type
 
     class function SyncKindName(Kind: TDMRSyncKind): string; static;
     property Enabled: Boolean read FEnabled;
+    property OnAudio: TDMRAudioEvent read FOnAudio write FOnAudio;
   end;
 
 implementation
@@ -275,6 +286,10 @@ begin
     FColorCode := 0;
     FLastDataType := 0;
     FSlotTypeCorrectedBits := 0;
+    FSelectedSlot := -1;
+    FVoiceFrameCount := 0;
+    FVoiceErrorCount := 0;
+    DMRMbeReset(FMbe);
     FTrackPhase := -1;
     FCurrentBurstPos := 0;
     FBurstCount := 0;
@@ -480,11 +495,51 @@ begin
       FLastLCSlot := 1
     else
       FLastLCSlot := 0;
+    if FSelectedSlot < 0 then FSelectedSlot := FLastLCSlot;
   end;
+  DecodeVoiceBurst;
   Inc(FBurstCount);
   FCurrentBurstPos := 0;
 end;
 
+procedure TDMRDecoder.DecodeVoiceBurst;
+var
+  Frames: TDMRAMBEFrames;
+  PCM: array[0..DMR_PCM_SAMPLES - 1] of Single;
+  MbeResult: TDMRMbeResult;
+  Slot, FrameIndex, RC: Integer;
+begin
+  if (FMbe = nil) or (FLastSyncTick = 0) or
+     (GetTickCount64 - FLastSyncTick > DMR_SYNC_HOLD_MS) then Exit;
+  if not (FSyncKind in [dskBSVoice, dskMSVoice, dskDirectTS1Voice,
+          dskDirectTS2Voice]) then Exit;
+
+  if FSyncKind in [dskBSVoice] then
+  begin
+    if not FLastBurstInfo.CACH.Valid then Exit;
+    Slot := FLastBurstInfo.CACH.Slot;
+  end
+  else if FSyncKind = dskDirectTS2Voice then Slot := 1
+  else Slot := 0;
+  if FSelectedSlot < 0 then FSelectedSlot := Slot;
+  if Slot <> FSelectedSlot then Exit;
+
+  DMRExtractAMBEFrames(FLastBurst, Frames);
+  for FrameIndex := 0 to 2 do
+  begin
+    FillChar(MbeResult, SizeOf(MbeResult), 0);
+    RC := DMRMbeDecode(FMbe, @Frames[FrameIndex][0], @PCM[0], @MbeResult);
+    if RC <> 0 then
+    begin
+      Inc(FVoiceErrorCount);
+      Continue;
+    end;
+    Inc(FVoiceFrameCount);
+    if MbeResult.ErrorsTotal > 0 then Inc(FVoiceErrorCount, MbeResult.ErrorsTotal);
+    if Assigned(FOnAudio) then FOnAudio(PCM, Length(PCM));
+  end;
+end;
+
 procedure TDMRDecoder.NoteSync(Phase: Integer; Kind: TDMRSyncKind;
   Inverted: Boolean);
 var
@@ -559,6 +614,9 @@ begin
       S.ServiceOptions := FLastLinkControl.ServiceOptions;
       S.TargetID := FLastLinkControl.TargetID;
       S.SourceID := FLastLinkControl.SourceID;
+      S.SelectedSlot := FSelectedSlot;
+      S.VoiceFrameCount := FVoiceFrameCount;
+      S.VoiceErrorCount := FVoiceErrorCount;
     finally
       FStatusLock.Leave;
     end;