attr: refactor attribute coding to produce IntegerLift variant

This commit reorganises the attribute coders to allow integration
of the RAHT variant.

tmc3/AttributeDecoder.cpp

@@ -163,6 +163,38 @@ int AttributeDecoder::decodeReflectances(
   const uint32_t alphabetSize = 64;
   decoder.start(bitstream, alphabetSize);
 
+  decodeReflectancesIntegerLift(decoder, pointCloud);
+
+  decoder.stop();
+  bitstream.size += compressedBitstreamSize;
+  return 0;
+}
+
+//----------------------------------------------------------------------------
+
+int AttributeDecoder::decodeColors(
+  PCCBitstream &bitstream,
+  PCCPointSet3 &pointCloud
+) {
+  uint32_t compressedBitstreamSize = 0;
+  PCCReadFromBuffer<uint32_t>(bitstream.buffer, compressedBitstreamSize, bitstream.size);
+  PCCResidualsDecoder decoder;
+  const uint32_t alphabetSize = 64;
+  decoder.start(bitstream, alphabetSize);
+
+  decodeColorsIntegerLift(decoder, pointCloud);
+
+  decoder.stop();
+  bitstream.size += compressedBitstreamSize;
+  return 0;
+}
+
+//----------------------------------------------------------------------------
+
+void AttributeDecoder::decodeReflectancesIntegerLift(
+  PCCResidualsDecoder &decoder,
+  PCCPointSet3 &pointCloud
+) {
   const size_t pointCount = predictors.size();
   for (size_t predictorIndex = 0; predictorIndex < pointCount; ++predictorIndex) {
     auto &predictor = predictors[predictorIndex];
@@ -176,23 +208,14 @@ int AttributeDecoder::decodeReflectances(
     reflectance = uint16_t(PCCClip(reconstructedQuantAttValue, int64_t(0),
                                    int64_t(std::numeric_limits<uint16_t>::max())));
   }
-  decoder.stop();
-  bitstream.size += compressedBitstreamSize;
-  return 0;
 }
 
 //----------------------------------------------------------------------------
 
-int AttributeDecoder::decodeColors(
-  PCCBitstream &bitstream,
+void AttributeDecoder::decodeColorsIntegerLift(
+  PCCResidualsDecoder &decoder,
   PCCPointSet3 &pointCloud
 ) {
-  uint32_t compressedBitstreamSize = 0;
-  PCCReadFromBuffer<uint32_t>(bitstream.buffer, compressedBitstreamSize, bitstream.size);
-  PCCResidualsDecoder decoder;
-  const uint32_t alphabetSize = 64;
-  decoder.start(bitstream, alphabetSize);
-
   const size_t pointCount = predictors.size();
   for (size_t predictorIndex = 0; predictorIndex < pointCount; ++predictorIndex) {
     auto &predictor = predictors[predictorIndex];
@@ -214,9 +237,6 @@ int AttributeDecoder::decodeColors(
       color[k] = uint8_t(PCCClip(reconstructedQuantAttValue, int64_t(0), int64_t(255)));
     }
   }
-  decoder.stop();
-  bitstream.size += compressedBitstreamSize;
-  return 0;
 }
 
 //============================================================================

tmc3/AttributeDecoder.h

@@ -45,6 +45,11 @@
 
 namespace pcc {
 
+//============================================================================
+// Opaque definitions (Internal detail)
+
+struct PCCResidualsDecoder;
+
 //============================================================================
 
 class AttributeDecoder {
@@ -52,18 +57,32 @@ public:
   void buildPredictors(
     const PCCPointSet3 &pointCloud);
 
+  // todo(df): return value is always 0 => should be void?
   int decodeHeader(
     const std::string &attributeName,
     PCCBitstream &bitstream);
 
+  // todo(df): return value is always 0 =>  should be void?
   int decodeReflectances(
     PCCBitstream &bitstream,
     PCCPointSet3 &pointCloud);
 
+  // todo(df): return value is always 0 => should be void?
   int decodeColors(
     PCCBitstream &bitstream,
     PCCPointSet3 &pointCloud);
 
+protected:
+  // todo(df): consider alternative encapsulation
+
+  void decodeReflectancesIntegerLift(
+    PCCResidualsDecoder &decoder,
+    PCCPointSet3 &pointCloud);
+
+  void decodeColorsIntegerLift(
+    PCCResidualsDecoder &decoder,
+    PCCPointSet3 &pointCloud);
+
 private:
   std::vector<PCCPredictor> predictors;
   std::vector<int64_t> quantizationSteps;

tmc3/AttributeEncoder.cpp

@@ -163,6 +163,42 @@ int AttributeEncoder::encodeReflectances(
   const uint32_t alphabetSize = 64;
   encoder.start(bitstream, alphabetSize);
 
+  encodeReflectancesIntegerLift(reflectanceParams, pointCloud, encoder);
+
+  uint32_t compressedBitstreamSize = encoder.stop();
+  bitstream.size += compressedBitstreamSize;
+  PCCWriteToBuffer<uint32_t>(compressedBitstreamSize, bitstream.buffer, startSize);
+  return 0;
+}
+
+//----------------------------------------------------------------------------
+
+int AttributeEncoder::encodeColors(
+  const PCCAttributeEncodeParamaters &colorParams,
+  PCCPointSet3 &pointCloud,
+  PCCBitstream &bitstream
+) {
+  uint64_t startSize = bitstream.size;
+  bitstream.size += 4;  // placehoder for bitstream size
+  PCCResidualsEncoder encoder;
+  const uint32_t alphabetSize = 64;
+  encoder.start(bitstream, alphabetSize);
+
+  encodeColorsIntegerLift(colorParams, pointCloud, encoder);
+
+  uint32_t compressedBitstreamSize = encoder.stop();
+  bitstream.size += compressedBitstreamSize;
+  PCCWriteToBuffer<uint32_t>(compressedBitstreamSize, bitstream.buffer, startSize);
+  return 0;
+}
+
+//----------------------------------------------------------------------------
+
+void AttributeEncoder::encodeReflectancesIntegerLift(
+  const PCCAttributeEncodeParamaters &reflectanceParams,
+  PCCPointSet3 &pointCloud,
+  PCCResidualsEncoder &encoder
+) {
   const size_t pointCount = predictors.size();
   for (size_t predictorIndex = 0; predictorIndex < pointCount; ++predictorIndex) {
     const auto &predictor = predictors[predictorIndex];
@@ -180,25 +216,15 @@ int AttributeEncoder::encodeReflectances(
     encoder.encode0(attValue0);
     pointCloud.setReflectance(predictor.index, reconstructedReflectance);
   }
-  uint32_t compressedBitstreamSize = encoder.stop();
-  bitstream.size += compressedBitstreamSize;
-  PCCWriteToBuffer<uint32_t>(compressedBitstreamSize, bitstream.buffer, startSize);
-  return 0;
 }
 
 //----------------------------------------------------------------------------
 
-int AttributeEncoder::encodeColors(
+void AttributeEncoder::encodeColorsIntegerLift(
   const PCCAttributeEncodeParamaters &colorParams,
   PCCPointSet3 &pointCloud,
-  PCCBitstream &bitstream
+  PCCResidualsEncoder &encoder
 ) {
-  uint64_t startSize = bitstream.size;
-  bitstream.size += 4;  // placehoder for bitstream size
-  PCCResidualsEncoder encoder;
-  const uint32_t alphabetSize = 64;
-  encoder.start(bitstream, alphabetSize);
-
   const size_t pointCount = predictors.size();
   for (size_t predictorIndex = 0; predictorIndex < pointCount; ++predictorIndex) {
     const auto &predictor = predictors[predictorIndex];
@@ -229,10 +255,6 @@ int AttributeEncoder::encodeColors(
     }
     pointCloud.setColor(predictor.index, reconstructedColor);
   }
-  uint32_t compressedBitstreamSize = encoder.stop();
-  bitstream.size += compressedBitstreamSize;
-  PCCWriteToBuffer<uint32_t>(compressedBitstreamSize, bitstream.buffer, startSize);
-  return 0;
 }
 
 //============================================================================

tmc3/AttributeEncoder.h

@@ -45,6 +45,11 @@
 
 namespace pcc {
 
+//============================================================================
+// Opaque definitions (Internal detail)
+
+struct PCCResidualsEncoder;
+
 //============================================================================
 
 struct PCCAttributeEncodeParamaters {
@@ -63,21 +68,37 @@ public:
     const PCCAttributeEncodeParamaters &attributeParams,
     const PCCPointSet3 &pointCloud);
 
+  // todo(df): return value is always 0 => should be void?
   int encodeHeader(
     const PCCAttributeEncodeParamaters &attributeParams,
     const std::string &attributeName,
     PCCBitstream &bitstream) const;
 
+  // todo(df): return value is always 0 => should be void?
   int encodeReflectances(
     const PCCAttributeEncodeParamaters &reflectanceParams,
     PCCPointSet3 &pointCloud,
     PCCBitstream &bitstream);
 
+  // todo(df): return value is always 0 => should be void?
   int encodeColors(
     const PCCAttributeEncodeParamaters &colorParams,
     PCCPointSet3 &pointCloud,
     PCCBitstream &bitstream);
 
+protected:
+  // todo(df): consider alternative encapsulation
+
+  void encodeReflectancesIntegerLift(
+    const PCCAttributeEncodeParamaters &reflectanceParams,
+    PCCPointSet3 &pointCloud,
+    PCCResidualsEncoder &encoder);
+
+  void encodeColorsIntegerLift(
+    const PCCAttributeEncodeParamaters &colorParams,
+    PCCPointSet3 &pointCloud,
+    PCCResidualsEncoder &encoder);
+
 private:
   std::vector<PCCPredictor> predictors;
 };