entropy/m43649: use schroarith for arithmetic coding

This commit provides an implementation of the entropy coding interface
using the dirac (schroedinger) arithmetic codec.

In order to handle any remaining m-ary symbols, a naïve unary
binarisation is employed.

tmc3/CMakeLists.txt

 cmake_minimum_required(VERSION 3.0)
+enable_language(C)
 
 if (UNIX)
   add_definitions(-D_POSIX_C_SOURCE=200809L)
@@ -73,6 +74,7 @@ file(GLOB PROJECT_INC_FILES
   "TMC3.h"
   "constants.h"
   "entropy.h"
+  "entropydirac.h"
   "entropyo3dgc.h"
   "entropyutils.h"
   "geometry.h"
@@ -91,6 +93,7 @@ file(GLOB PROJECT_INC_FILES
   "../dependencies/nanoflann/*.h"
   "../dependencies/arithmetic-coding/inc/*.h"
   "../dependencies/program-options-lite/*.h"
+  "../dependencies/schroedinger/schroarith.h"
 )
 
 file(GLOB PROJECT_CPP_FILES
@@ -102,6 +105,7 @@ file(GLOB PROJECT_CPP_FILES
   "TMC3.cpp"
   "decoder.cpp"
   "encoder.cpp"
+  "entropydirac.cpp"
   "geometry_intra_pred.cpp"
   "geometry_octree.cpp"
   "geometry_octree_decoder.cpp"
@@ -115,6 +119,7 @@ file(GLOB PROJECT_CPP_FILES
   "tables.cpp"
   "../dependencies/arithmetic-coding/src/*.cpp"
   "../dependencies/program-options-lite/*.cpp"
+  "../dependencies/schroedinger/schroarith.c"
 )
 
 source_group (inc FILES ${PROJECT_INC_FILES})
@@ -123,6 +128,7 @@ source_group (cpp FILES ${PROJECT_CPP_FILES})
 
 include_directories(
   "${PROJECT_BINARY_DIR}/tmc3"
+  "${PROJECT_SOURCE_DIR}"
   "${CMAKE_CURRENT_SOURCE_DIR}"
   "${CMAKE_CURRENT_SOURCE_DIR}/../dependencies/nanoflann"
   "${CMAKE_CURRENT_SOURCE_DIR}/../dependencies/arithmetic-coding/inc"

tmc3/entropy.h

@@ -35,17 +35,26 @@
 
 #pragma once
 
-#define ENTROPY_O3DGC 1
+#define ENTROPY_O3DGC 0
+#define ENTROPY_DIRAC 1
 
 #if ENTROPY_O3DGC
 #  include "entropyo3dgc.h"
 #endif
 
+#if ENTROPY_DIRAC
+#  include "entropydirac.h"
+#endif
+
 #include "entropyutils.h"
 
-#if ENTROPY_O3DGC
 namespace pcc {
+#if ENTROPY_O3DGC
 using EntropyEncoder = EntropyEncoderWrapper<o3dgc::ArithmeticEncoder>;
 using EntropyDecoder = EntropyDecoderWrapper<o3dgc::ArithmeticDecoder>;
-}  // namespace pcc
 #endif
+#if ENTROPY_DIRAC
+using EntropyEncoder = EntropyEncoderWrapper<dirac::ArithmeticEncoder>;
+using EntropyDecoder = EntropyDecoderWrapper<dirac::ArithmeticDecoder>;
+#endif
+}  // namespace pcc

tmc3/entropydirac.cpp

+/* The copyright in this software is being made available under the BSD
+ * Licence, included below.  This software may be subject to other third
+ * party and contributor rights, including patent rights, and no such
+ * rights are granted under this licence.
+ *
+ * Copyright (c) 2017-2018, ISO/IEC
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * * Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ *
+ * * Redistributions in binary form must reproduce the above copyright
+ *   notice, this list of conditions and the following disclaimer in the
+ *   documentation and/or other materials provided with the distribution.
+ *
+ * * Neither the name of the ISO/IEC nor the names of its contributors
+ *   may be used to endorse or promote products derived from this
+ *   software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "entropydirac.h"
+
+#include "PCCMisc.h"
+
+#include <algorithm>
+
+namespace pcc {
+namespace dirac {
+
+  //=========================================================================
+
+  void SchroMAryContext::set_alphabet(int numsyms)
+  {
+    // initialise all contexts with p = 0.5
+    this->numsyms = numsyms;
+    this->probabilities = std::vector<uint16_t>(numsyms, 0x8000);
+  }
+
+  //=========================================================================
+
+  void ArithmeticEncoder::encode(int sym, SchroMAryContext& model)
+  {
+    int ctxidx = 0;
+
+    while (sym-- > 0) {
+      schro_arith_encode_bit(&impl, &model.probabilities[ctxidx++], 1);
+    }
+    // todo(df): this should be truncated unary coded
+    schro_arith_encode_bit(&impl, &model.probabilities[ctxidx], 0);
+  }
+
+  //=========================================================================
+
+  int ArithmeticDecoder::decode(SchroMAryContext& model)
+  {
+    int ctxidx = 0;
+    int sym = 0;
+
+    while (schro_arith_decode_bit(&impl, &model.probabilities[ctxidx++])) {
+      sym++;
+    }
+
+    return sym;
+  }
+
+  //==========================================================================
+
+}  // namespace dirac
+}  // namespace pcc

tmc3/entropydirac.h

+/* The copyright in this software is being made available under the BSD
+ * Licence, included below.  This software may be subject to other third
+ * party and contributor rights, including patent rights, and no such
+ * rights are granted under this licence.
+ *
+ * Copyright (c) 2017-2018, ISO/IEC
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * * Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ *
+ * * Redistributions in binary form must reproduce the above copyright
+ *   notice, this list of conditions and the following disclaimer in the
+ *   documentation and/or other materials provided with the distribution.
+ *
+ * * Neither the name of the ISO/IEC nor the names of its contributors
+ *   may be used to endorse or promote products derived from this
+ *   software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#pragma once
+
+#include "dependencies/schroedinger/schroarith.h"
+
+#include <assert.h>
+#include <stdlib.h>
+#include <memory>
+#include <vector>
+
+namespace pcc {
+namespace dirac {
+
+  //==========================================================================
+
+  struct SchroContext {
+    uint16_t probability = 0x8000;  // p=0.5
+
+    template<class... Args>
+    void reset(Args...)
+    {
+      probability = 0x8000;
+    }
+  };
+
+  //==========================================================================
+
+  struct SchroContextFixed {
+    //uint16_t probability = 0x8000; // p=0.5
+  };
+
+  //==========================================================================
+  // context definition that automatically binarises an m-ary symbol
+
+  struct SchroMAryContext {
+    SchroMAryContext() = default;
+
+    SchroMAryContext(int numsyms) { set_alphabet(numsyms); }
+
+    void set_alphabet(int numsyms);
+
+    int numsyms;
+    std::vector<uint16_t> probabilities;
+  };
+
+  //==========================================================================
+
+  struct InvalidContext {
+    void set_alphabet(int) {}
+  };
+
+  //==========================================================================
+
+  class ArithmeticEncoder {
+  public:
+    ArithmeticEncoder() = default;
+    ArithmeticEncoder(size_t bufferSize, std::nullptr_t)
+    {
+      setBuffer(bufferSize, nullptr);
+    }
+
+    //------------------------------------------------------------------------
+
+    void setBuffer(size_t size, uint8_t* buffer)
+    {
+      buf.length = int(size);
+
+      if (buffer)
+        buf.data = buffer;
+      else {
+        allocatedBuffer.reset(new uint8_t[size]);
+        buf.data = allocatedBuffer.get();
+      }
+    }
+
+    //------------------------------------------------------------------------
+
+    void start() { schro_arith_encode_init(&impl, &buf); }
+
+    //------------------------------------------------------------------------
+
+    size_t stop()
+    {
+      schro_arith_flush(&impl);
+      return impl.offset;
+    }
+
+    //------------------------------------------------------------------------
+
+    const char* buffer() { return reinterpret_cast<char*>(buf.data); }
+
+    //------------------------------------------------------------------------
+
+    void encode(int bit, SchroContextFixed& model)
+    {
+      uint16_t probability = 0x8000;  // p=0.5
+      schro_arith_encode_bit(&impl, &probability, bit);
+    }
+
+    //------------------------------------------------------------------------
+
+    void encode(int data, SchroMAryContext& model);
+
+    //------------------------------------------------------------------------
+
+    void encode(int data, InvalidContext& model) { assert(0); }
+
+    void encode(int bit, SchroContext& model)
+    {
+      schro_arith_encode_bit(&impl, &model.probability, bit);
+    }
+
+    //------------------------------------------------------------------------
+
+  private:
+    ::SchroArith impl;
+    ::SchroBuffer buf;
+    std::unique_ptr<uint8_t[]> allocatedBuffer;
+  };
+
+  //==========================================================================
+
+  class ArithmeticDecoder {
+  public:
+    void setBuffer(size_t size, const char* buffer)
+    {
+      buf.data = reinterpret_cast<uint8_t*>(const_cast<char*>(buffer));
+      buf.length = int(size);
+    }
+
+    //------------------------------------------------------------------------
+
+    void start() { schro_arith_decode_init(&impl, &buf); }
+
+    //------------------------------------------------------------------------
+
+    void stop() { schro_arith_decode_flush(&impl); }
+
+    //------------------------------------------------------------------------
+
+    int decode(SchroContextFixed& model)
+    {
+      uint16_t probability = 0x8000;  // p=0.5
+      return schro_arith_decode_bit(&impl, &probability);
+    }
+
+    //------------------------------------------------------------------------
+
+    int decode(SchroMAryContext& model);
+
+    //------------------------------------------------------------------------
+
+    int decode(InvalidContext& model)
+    {
+      assert(0);
+      return 0;
+    }
+
+    //------------------------------------------------------------------------
+
+    int decode(SchroContext& model)
+    {
+      return schro_arith_decode_bit(&impl, &model.probability);
+    }
+
+    //------------------------------------------------------------------------
+
+  private:
+    ::SchroArith impl;
+    ::SchroBuffer buf;
+  };
+
+  //==========================================================================
+
+}  // namespace dirac
+
+using StaticBitModel = dirac::SchroContextFixed;
+using StaticMAryModel = dirac::InvalidContext;
+using AdaptiveBitModel = dirac::SchroContext;
+using AdaptiveBitModelFast = dirac::SchroContext;
+using AdaptiveMAryModel = dirac::SchroMAryContext;
+
+//============================================================================
+
+}  // namespace pcc