attr: restrict PCCTMC3MaxPredictionNearestNeighborCount to 3

This commit updates the hard coded limit and default values, and
updates the master configuration template.

cfg/cat3-tmc13-ctc-lossless-geom-lossless-attrs.yaml

@@ -27,7 +27,7 @@ categories:
       citytunnel_q1mm:
         encflags:
          - &mitsubishiLosslessAttrs
-            - numberOfNearestNeighborsInPrediction: 4
+            - numberOfNearestNeighborsInPrediction: 3
             - levelOfDetailCount: 9
             - dist2: 134217728 33554432 8388608 2097152 524288 131072 32768 8192 0
             - quantizationStepsLuma: 0 0 0 0 0 0 0 0 0
@@ -86,7 +86,7 @@ categories:
       ford_03_q1mm:
         encflags:
          - &fordLosslessAttrs
-            - numberOfNearestNeighborsInPrediction: 4
+            - numberOfNearestNeighborsInPrediction: 3
             - levelOfDetailCount: 6
             - dist2: 4194301 1048582 262149 65534 16383 0
             - quantizationStepsLuma: 0 0 0 0 0 0

cfg/cat3-tmc13-ctc-lossless-geom-lossy-attrs.yaml

@@ -28,7 +28,7 @@ categories:
       citytunnel_q1mm:
         encflags:
          - &commonAttr
-           - numberOfNearestNeighborsInPrediction: 4
+           - numberOfNearestNeighborsInPrediction: 3
            - levelOfDetailCount: 9
            - dist2: 134217728 33554432 8388608 2097152 524288 131072 32768 8192 0
          - quantizationStepsLuma:

cfg/cat3-tmc13-ctc-lossless-geom-nearlossless-attrs.yaml

@@ -28,7 +28,7 @@ categories:
       citytunnel_q1mm:
         encflags:
          - &mitsubishiNearlosslessAttrs
-            - numberOfNearestNeighborsInPrediction: 4
+            - numberOfNearestNeighborsInPrediction: 3
             - levelOfDetailCount: 9
             - dist2: 134217728 33554432 8388608 2097152 524288 131072 32768 8192 0
             - quantizationStepsLuma:
@@ -98,7 +98,7 @@ categories:
       ford_03_q1mm:
         encflags:
          - &fordNearlosslessAttrs
-            - numberOfNearestNeighborsInPrediction: 4
+            - numberOfNearestNeighborsInPrediction: 3
             - levelOfDetailCount: 6
             - dist2: 4194301 1048582 262149 65534 16383 0
             - quantizationStepsLuma:

tmc3/PCCTMC3Common.h

@@ -49,7 +49,7 @@
 #include <vector>
 
 namespace pcc {
-const uint32_t PCCTMC3MaxPredictionNearestNeighborCount = 4;
+const uint32_t PCCTMC3MaxPredictionNearestNeighborCount = 3;
 const uint32_t PCCTMC3SymbolCount = 64;
 
 const int MAX_NUM_DM_LEAF_POINTS = 2;

tmc3/TMC3.cpp

@@ -329,7 +329,7 @@ ParseParameters(int argc, char* argv[], Parameters& params)
     "component")
 
   ("numberOfNearestNeighborsInPrediction",
-    params_attr.aps.num_pred_nearest_neighbours, 4,
+    params_attr.aps.num_pred_nearest_neighbours, 3,
     "Attribute's maximum number of nearest neighbors to be used for prediction")
 
   ("adaptivePredictionThreshold",
@@ -459,10 +459,9 @@ ParseParameters(int argc, char* argv[], Parameters& params)
       if (
         attr_aps.num_pred_nearest_neighbours
         > PCCTMC3MaxPredictionNearestNeighborCount) {
-        err.error()
-          << it.first
-          << ".numberOfNearestNeighborsInPrediction must be less than "
-          << PCCTMC3MaxPredictionNearestNeighborCount << "\n";
+        err.error() << it.first
+                    << ".numberOfNearestNeighborsInPrediction must be <= "
+                    << PCCTMC3MaxPredictionNearestNeighborCount << "\n";
       }
     }
   }