1 files changed, 101 insertions, 0 deletions
diff --git a/src/dsp/distance_weighted_blend.cc b/src/dsp/distance_weighted_blend.cc
new file mode 100644
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--- /dev/null
+++ b/src/dsp/distance_weighted_blend.cc
@@ -0,0 +1,101 @@
+// Copyright 2019 The libgav1 Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "src/dsp/distance_weighted_blend.h"
+
+#include <cassert>
+#include <cstddef>
+#include <cstdint>
+#include <type_traits>
+
+#include "src/dsp/dsp.h"
+#include "src/utils/common.h"
+
+namespace libgav1 {
+namespace dsp {
+namespace {
+
+template <int bitdepth, typename Pixel>
+void DistanceWeightedBlend_C(const void* prediction_0, const void* prediction_1,
+                             const uint8_t weight_0, const uint8_t weight_1,
+                             const int width, const int height,
+                             void* const dest, const ptrdiff_t dest_stride) {
+  // 7.11.3.2 Rounding variables derivation process
+  //   2 * FILTER_BITS(7) - (InterRound0(3|5) + InterRound1(7))
+  constexpr int inter_post_round_bits = (bitdepth == 12) ? 2 : 4;
+  using PredType =
+      typename std::conditional<bitdepth == 8, int16_t, uint16_t>::type;
+  const auto* pred_0 = static_cast<const PredType*>(prediction_0);
+  const auto* pred_1 = static_cast<const PredType*>(prediction_1);
+  auto* dst = static_cast<Pixel*>(dest);
+  const ptrdiff_t dst_stride = dest_stride / sizeof(Pixel);
+
+  int y = 0;
+  do {
+    int x = 0;
+    do {
+      // See warp.cc and convolve.cc for detailed prediction ranges.
+      // weight_0 + weight_1 = 16.
+      int res = pred_0[x] * weight_0 + pred_1[x] * weight_1;
+      res -= (bitdepth == 8) ? 0 : kCompoundOffset * 16;
+      dst[x] = static_cast<Pixel>(
+          Clip3(RightShiftWithRounding(res, inter_post_round_bits + 4), 0,
+                (1 << bitdepth) - 1));
+    } while (++x < width);
+
+    dst += dst_stride;
+    pred_0 += width;
+    pred_1 += width;
+  } while (++y < height);
+}
+
+void Init8bpp() {
+  Dsp* const dsp = dsp_internal::GetWritableDspTable(8);
+  assert(dsp != nullptr);
+#if LIBGAV1_ENABLE_ALL_DSP_FUNCTIONS
+  dsp->distance_weighted_blend = DistanceWeightedBlend_C<8, uint8_t>;
+#else  // !LIBGAV1_ENABLE_ALL_DSP_FUNCTIONS
+  static_cast<void>(dsp);
+#ifndef LIBGAV1_Dsp8bpp_DistanceWeightedBlend
+  dsp->distance_weighted_blend = DistanceWeightedBlend_C<8, uint8_t>;
+#endif
+#endif  // LIBGAV1_ENABLE_ALL_DSP_FUNCTIONS
+}
+
+#if LIBGAV1_MAX_BITDEPTH >= 10
+void Init10bpp() {
+  Dsp* const dsp = dsp_internal::GetWritableDspTable(10);
+  assert(dsp != nullptr);
+#if LIBGAV1_ENABLE_ALL_DSP_FUNCTIONS
+  dsp->distance_weighted_blend = DistanceWeightedBlend_C<10, uint16_t>;
+#else  // !LIBGAV1_ENABLE_ALL_DSP_FUNCTIONS
+  static_cast<void>(dsp);
+#ifndef LIBGAV1_Dsp10bpp_DistanceWeightedBlend
+  dsp->distance_weighted_blend = DistanceWeightedBlend_C<10, uint16_t>;
+#endif
+#endif  // LIBGAV1_ENABLE_ALL_DSP_FUNCTIONS
+}
+#endif
+
+}  // namespace
+
+void DistanceWeightedBlendInit_C() {
+  Init8bpp();
+#if LIBGAV1_MAX_BITDEPTH >= 10
+  Init10bpp();
+#endif
+}
+
+}  // namespace dsp
+}  // namespace libgav1