Import aom library

This is the reference implementation for the Alliance for Open Media's av1 video code.

The commit used was 4d668d7feb1f8abd809d1bca0418570a7f142a36.

1 files changed, 211 insertions, 0 deletions

diff --git a/third_party/aom/aom_dsp/binary_codes_writer.c b/third_party/aom/aom_dsp/binary_codes_writer.c
new file mode 100644
index 000000000..91e807b29
--- /dev/null
+++ b/third_party/aom/aom_dsp/binary_codes_writer.c
@@ -0,0 +1,211 @@
+/*
+ * Copyright (c) 2017, Alliance for Open Media. All rights reserved
+ *
+ * This source code is subject to the terms of the BSD 2 Clause License and
+ * the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License
+ * was not distributed with this source code in the LICENSE file, you can
+ * obtain it at www.aomedia.org/license/software. If the Alliance for Open
+ * Media Patent License 1.0 was not distributed with this source code in the
+ * PATENTS file, you can obtain it at www.aomedia.org/license/patent.
+ */
+
+#include "aom_dsp/bitwriter.h"
+
+#include "av1/common/common.h"
+
+// Recenters a non-negative literal v around a reference r
+static uint16_t recenter_nonneg(uint16_t r, uint16_t v) {
+  if (v > (r << 1))
+    return v;
+  else if (v >= r)
+    return ((v - r) << 1);
+  else
+    return ((r - v) << 1) - 1;
+}
+
+// Recenters a non-negative literal v in [0, n-1] around a
+// reference r also in [0, n-1]
+static uint16_t recenter_finite_nonneg(uint16_t n, uint16_t r, uint16_t v) {
+  if ((r << 1) <= n) {
+    return recenter_nonneg(r, v);
+  } else {
+    return recenter_nonneg(n - 1 - r, n - 1 - v);
+  }
+}
+
+// Codes a symbol v in [-2^mag_bits, 2^mag_bits].
+// mag_bits is number of bits for magnitude. The alphabet is of size
+// 2 * 2^mag_bits + 1, symmetric around 0, where one bit is used to
+// indicate 0 or non-zero, mag_bits bits are used to indicate magnitide
+// and 1 more bit for the sign if non-zero.
+void aom_write_primitive_symmetric(aom_writer *w, int16_t v,
+                                   unsigned int abs_bits) {
+  if (v == 0) {
+    aom_write_bit(w, 0);
+  } else {
+    const int x = abs(v);
+    const int s = v < 0;
+    aom_write_bit(w, 1);
+    aom_write_bit(w, s);
+    aom_write_literal(w, x - 1, abs_bits);
+  }
+}
+
+int aom_count_primitive_symmetric(int16_t v, unsigned int abs_bits) {
+  return (v == 0 ? 1 : abs_bits + 2);
+}
+
+// Encodes a value v in [0, n-1] quasi-uniformly
+void aom_write_primitive_quniform(aom_writer *w, uint16_t n, uint16_t v) {
+  if (n <= 1) return;
+  const int l = get_msb(n - 1) + 1;
+  const int m = (1 << l) - n;
+  if (v < m) {
+    aom_write_literal(w, v, l - 1);
+  } else {
+    aom_write_literal(w, m + ((v - m) >> 1), l - 1);
+    aom_write_bit(w, (v - m) & 1);
+  }
+}
+
+int aom_count_primitive_quniform(uint16_t n, uint16_t v) {
+  if (n <= 1) return 0;
+  const int l = get_msb(n - 1) + 1;
+  const int m = (1 << l) - n;
+  return v < m ? l - 1 : l;
+}
+
+// Encodes a value v in [0, n-1] based on a reference ref also in [0, n-1]
+// The closest p values of v from ref are coded using a p-ary quasi-unoform
+// short code while the remaining n-p values are coded with a longer code.
+void aom_write_primitive_refbilevel(aom_writer *w, uint16_t n, uint16_t p,
+                                    uint16_t ref, uint16_t v) {
+  if (n <= 1) return;
+  assert(p > 0 && p <= n);
+  assert(ref < n);
+  int lolimit = ref - p / 2;
+  int hilimit = lolimit + p - 1;
+  if (lolimit < 0) {
+    lolimit = 0;
+    hilimit = p - 1;
+  } else if (hilimit >= n) {
+    hilimit = n - 1;
+    lolimit = n - p;
+  }
+  if (v >= lolimit && v <= hilimit) {
+    aom_write_bit(w, 1);
+    v = v - lolimit;
+    aom_write_primitive_quniform(w, p, v);
+  } else {
+    aom_write_bit(w, 0);
+    if (v > hilimit) v -= p;
+    aom_write_primitive_quniform(w, n - p, v);
+  }
+}
+
+int aom_count_primitive_refbilevel(uint16_t n, uint16_t p, uint16_t ref,
+                                   uint16_t v) {
+  if (n <= 1) return 0;
+  assert(p > 0 && p <= n);
+  assert(ref < n);
+  int lolimit = ref - p / 2;
+  int hilimit = lolimit + p - 1;
+  if (lolimit < 0) {
+    lolimit = 0;
+    hilimit = p - 1;
+  } else if (hilimit >= n) {
+    hilimit = n - 1;
+    lolimit = n - p;
+  }
+  int count = 0;
+  if (v >= lolimit && v <= hilimit) {
+    count++;
+    v = v - lolimit;
+    count += aom_count_primitive_quniform(p, v);
+  } else {
+    count++;
+    if (v > hilimit) v -= p;
+    count += aom_count_primitive_quniform(n - p, v);
+  }
+  return count;
+}
+
+// Finite subexponential code that codes a symbol v in [0, n-1] with parameter k
+void aom_write_primitive_subexpfin(aom_writer *w, uint16_t n, uint16_t k,
+                                   uint16_t v) {
+  int i = 0;
+  int mk = 0;
+  while (1) {
+    int b = (i ? k + i - 1 : k);
+    int a = (1 << b);
+    if (n <= mk + 3 * a) {
+      aom_write_primitive_quniform(w, n - mk, v - mk);
+      break;
+    } else {
+      int t = (v >= mk + a);
+      aom_write_bit(w, t);
+      if (t) {
+        i = i + 1;
+        mk += a;
+      } else {
+        aom_write_literal(w, v - mk, b);
+        break;
+      }
+    }
+  }
+}
+
+int aom_count_primitive_subexpfin(uint16_t n, uint16_t k, uint16_t v) {
+  int count = 0;
+  int i = 0;
+  int mk = 0;
+  while (1) {
+    int b = (i ? k + i - 1 : k);
+    int a = (1 << b);
+    if (n <= mk + 3 * a) {
+      count += aom_count_primitive_quniform(n - mk, v - mk);
+      break;
+    } else {
+      int t = (v >= mk + a);
+      count++;
+      if (t) {
+        i = i + 1;
+        mk += a;
+      } else {
+        count += b;
+        break;
+      }
+    }
+  }
+  return count;
+}
+
+// Finite subexponential code that codes a symbol v in [0, n-1] with parameter k
+// based on a reference ref also in [0, n-1].
+// Recenters symbol around r first and then uses a finite subexponential code.
+void aom_write_primitive_refsubexpfin(aom_writer *w, uint16_t n, uint16_t k,
+                                      int16_t ref, int16_t v) {
+  aom_write_primitive_subexpfin(w, n, k, recenter_finite_nonneg(n, ref, v));
+}
+
+void aom_write_signed_primitive_refsubexpfin(aom_writer *w, uint16_t n,
+                                             uint16_t k, uint16_t ref,
+                                             uint16_t v) {
+  ref += n - 1;
+  v += n - 1;
+  const uint16_t scaled_n = (n << 1) - 1;
+  aom_write_primitive_refsubexpfin(w, scaled_n, k, ref, v);
+}
+
+int aom_count_primitive_refsubexpfin(uint16_t n, uint16_t k, uint16_t ref,
+                                     uint16_t v) {
+  return aom_count_primitive_subexpfin(n, k, recenter_finite_nonneg(n, ref, v));
+}
+
+int aom_count_signed_primitive_refsubexpfin(uint16_t n, uint16_t k, int16_t ref,
+                                            int16_t v) {
+  ref += n - 1;
+  v += n - 1;
+  const uint16_t scaled_n = (n << 1) - 1;
+  return aom_count_primitive_refsubexpfin(scaled_n, k, ref, v);
+}