hls: refactor LoD presence test into aps.lodParametersPresent()

Rather than testing for the attribute encoding in various places in
order to determine the use of LoDs, use the derivation
lodParametersPresent instead.

tmc3/AttributeDecoder.cpp

@@ -209,13 +209,8 @@ AttributeDecoder::decode(
   decoder.start(sps, payload.data() + abhSize, payload.size() - abhSize);
 
   // generate LoDs if necessary
-  switch (attr_aps.attr_encoding) {
-  case AttributeEncoding::kLiftingTransform:
-  case AttributeEncoding::kPredictingTransform:
-    if (_lods.empty())
-      _lods.generate(attr_aps, minGeomNodeSizeLog2, pointCloud);
-  default: break;
-  }
+  if (attr_aps.lodParametersPresent() && _lods.empty())
+    _lods.generate(attr_aps, minGeomNodeSizeLog2, pointCloud);
 
   if (attr_desc.attr_num_dimensions == 1) {
     switch (attr_aps.attr_encoding) {

tmc3/AttributeEncoder.cpp

@@ -357,13 +357,8 @@ AttributeEncoder::encode(
   encoder.start(sps, int(pointCloud.getPointCount()));
 
   // generate LoDs if necessary
-  switch (attr_aps.attr_encoding) {
-  case AttributeEncoding::kLiftingTransform:
-  case AttributeEncoding::kPredictingTransform:
-    if (_lods.empty())
+  if (attr_aps.lodParametersPresent() && _lods.empty())
       _lods.generate(attr_aps, 0, pointCloud);
-  default: break;
-  }
 
   if (desc.attr_num_dimensions == 1) {
     switch (attr_aps.attr_encoding) {

tmc3/TMC3.cpp

@@ -839,12 +839,8 @@ ParseParameters(int argc, char* argv[], Parameters& params)
     if (attr_sps.cicp_matrix_coefficients_idx == ColourMatrix::kYCgCo)
       attr_sps.attr_bitdepth_secondary++;
 
-    bool isLifting =
-      attr_aps.attr_encoding == AttributeEncoding::kPredictingTransform
-      || attr_aps.attr_encoding == AttributeEncoding::kLiftingTransform;
-
     // derive the dist2 values based on an initial value
-    if (isLifting) {
+    if (attr_aps.lodParametersPresent()) {
       if (attr_aps.dist2.size() > attr_aps.num_detail_levels) {
         attr_aps.dist2.resize(attr_aps.num_detail_levels);
       } else if (
@@ -917,17 +913,13 @@ ParseParameters(int argc, char* argv[], Parameters& params)
       }
     }
 
-    bool isLifting =
-      attr_aps.attr_encoding == AttributeEncoding::kPredictingTransform
-      || attr_aps.attr_encoding == AttributeEncoding::kLiftingTransform;
-
     if (attr_sps.attr_bitdepth > 16)
       err.error() << it.first << ".bitdepth must be less than 17\n";
 
     if (attr_sps.attr_bitdepth_secondary > 16)
       err.error() << it.first << ".bitdepth_secondary must be less than 17\n";
 
-    if (isLifting) {
+    if (attr_aps.lodParametersPresent()) {
       int lod = attr_aps.num_detail_levels;
       if (lod > 255 || lod < 0) {
         err.error() << it.first

tmc3/hls.h

@@ -349,6 +349,11 @@ struct AttributeParameterSet {
   int aps_seq_parameter_set_id;
   AttributeEncoding attr_encoding;
 
+  bool lodParametersPresent() const {
+    return attr_encoding == AttributeEncoding::kLiftingTransform
+      || attr_encoding == AttributeEncoding::kPredictingTransform;
+  }
+
   //--- lifting/predicting transform parameters
 
   bool lod_decimation_enabled_flag;

tmc3/io_hls.cpp

@@ -317,9 +317,7 @@ write(const AttributeParameterSet& aps)
   bs.writeSe(aps.aps_chroma_qp_offset);
   bs.write(aps.aps_slice_qp_deltas_present_flag);
 
-  bool isLifting = aps.attr_encoding == AttributeEncoding::kLiftingTransform
-    || aps.attr_encoding == AttributeEncoding::kPredictingTransform;
-  if (isLifting) {
+  if (aps.lodParametersPresent()) {
     bs.writeUe(aps.num_pred_nearest_neighbours);
     bs.writeUe(aps.search_range);
     bs.writeUe(aps.num_detail_levels);
@@ -376,9 +374,7 @@ parseAps(const PayloadBuffer& buf)
   bs.readSe(&aps.aps_chroma_qp_offset);
   bs.read(&aps.aps_slice_qp_deltas_present_flag);
 
-  bool isLifting = aps.attr_encoding == AttributeEncoding::kLiftingTransform
-    || aps.attr_encoding == AttributeEncoding::kPredictingTransform;
-  if (isLifting) {
+  if (aps.lodParametersPresent()) {
     bs.readUe(&aps.num_pred_nearest_neighbours);
     bs.readUe(&aps.search_range);
     bs.readUe(&aps.num_detail_levels);