libvpx: Add VP9 decoder.

source/libvpx/vp9/common/vp9_quant_common.c

+/*
+ *  Copyright (c) 2010 The WebM project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+
+#include "vp9/common/vp9_quant_common.h"
+
+static int dc_qlookup[QINDEX_RANGE];
+static int ac_qlookup[QINDEX_RANGE];
+
+#define ACDC_MIN 4
+
+void vp9_init_quant_tables() {
+  int i;
+  int current_val = 4;
+  int last_val = 4;
+  int ac_val;
+
+  for (i = 0; i < QINDEX_RANGE; i++) {
+    ac_qlookup[i] = current_val;
+    current_val = (int)((double)current_val * 1.02);
+    if (current_val == last_val)
+      current_val++;
+    last_val = current_val;
+
+    ac_val = ac_qlookup[i];
+    dc_qlookup[i] = (int)((0.000000305 * ac_val * ac_val * ac_val) +
+                          (-0.00065 * ac_val * ac_val) +
+                          (0.9 * ac_val) + 0.5);
+    if (dc_qlookup[i] < ACDC_MIN)
+      dc_qlookup[i] = ACDC_MIN;
+  }
+}
+
+int vp9_dc_quant(int QIndex, int Delta) {
+  int retval;
+
+  QIndex = QIndex + Delta;
+
+  if (QIndex > MAXQ)
+    QIndex = MAXQ;
+  else if (QIndex < 0)
+    QIndex = 0;
+
+  retval = dc_qlookup[ QIndex ];
+  return retval;
+}
+
+int vp9_dc2quant(int QIndex, int Delta) {
+  int retval;
+
+  QIndex = QIndex + Delta;
+
+  if (QIndex > MAXQ)
+    QIndex = MAXQ;
+  else if (QIndex < 0)
+    QIndex = 0;
+
+  retval = dc_qlookup[ QIndex ];
+
+  return retval;
+
+}
+int vp9_dc_uv_quant(int QIndex, int Delta) {
+  int retval;
+
+  QIndex = QIndex + Delta;
+
+  if (QIndex > MAXQ)
+    QIndex = MAXQ;
+  else if (QIndex < 0)
+    QIndex = 0;
+
+  retval = dc_qlookup[ QIndex ];
+
+  return retval;
+}
+
+int vp9_ac_yquant(int QIndex) {
+  int retval;
+
+  if (QIndex > MAXQ)
+    QIndex = MAXQ;
+  else if (QIndex < 0)
+    QIndex = 0;
+
+  retval = ac_qlookup[ QIndex ];
+  return retval;
+}
+
+int vp9_ac2quant(int QIndex, int Delta) {
+  int retval;
+
+  QIndex = QIndex + Delta;
+
+  if (QIndex > MAXQ)
+    QIndex = MAXQ;
+  else if (QIndex < 0)
+    QIndex = 0;
+
+  retval = (ac_qlookup[ QIndex ] * 775) / 1000;
+  if (retval < 4)
+    retval = 4;
+
+  return retval;
+}
+int vp9_ac_uv_quant(int QIndex, int Delta) {
+  int retval;
+
+  QIndex = QIndex + Delta;
+
+  if (QIndex > MAXQ)
+    QIndex = MAXQ;
+  else if (QIndex < 0)
+    QIndex = 0;
+
+  retval = ac_qlookup[ QIndex ];
+  return retval;
+}