Initial check in of stagefright software AAC decoder based on PV source code.

1 files changed, 168 insertions, 0 deletions

diff --git a/media/libstagefright/codecs/aacdec/pv_log2.cpp b/media/libstagefright/codecs/aacdec/pv_log2.cpp
new file mode 100644
index 0000000..69cbe91
--- /dev/null
+++ b/media/libstagefright/codecs/aacdec/pv_log2.cpp
@@ -0,0 +1,168 @@
+/* ------------------------------------------------------------------
+ * Copyright (C) 1998-2009 PacketVideo
+ *
+ * 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.
+ * -------------------------------------------------------------------
+ */
+/*
+
+ Filename: pv_log2.c
+
+------------------------------------------------------------------------------
+ REVISION HISTORY
+
+
+ Who:                                   Date: MM/DD/YYYY
+ Description:
+
+------------------------------------------------------------------------------
+ INPUT AND OUTPUT DEFINITIONS
+
+    Int32 x             32-bit integer input
+
+
+------------------------------------------------------------------------------
+ FUNCTION DESCRIPTION
+
+    Implement the logarithm base 2 of a number
+------------------------------------------------------------------------------
+ REQUIREMENTS
+
+
+------------------------------------------------------------------------------
+ REFERENCES
+
+------------------------------------------------------------------------------
+ PSEUDO-CODE
+
+------------------------------------------------------------------------------
+*/
+
+
+/*----------------------------------------------------------------------------
+; INCLUDES
+----------------------------------------------------------------------------*/
+
+#ifdef AAC_PLUS
+
+
+#include "pv_log2.h"
+#include "fxp_mul32.h"
+
+/*----------------------------------------------------------------------------
+; MACROS
+; Define module specific macros here
+----------------------------------------------------------------------------*/
+
+
+/*----------------------------------------------------------------------------
+; DEFINES
+; Include all pre-processor statements here. Include conditional
+; compile variables also.
+----------------------------------------------------------------------------*/
+
+/*----------------------------------------------------------------------------
+; LOCAL FUNCTION DEFINITIONS
+; Function Prototype declaration
+----------------------------------------------------------------------------*/
+
+/*----------------------------------------------------------------------------
+; LOCAL STORE/BUFFER/POINTER DEFINITIONS
+; Variable declaration - defined here and used outside this module
+----------------------------------------------------------------------------*/
+
+#define R_SHIFT     20
+#define Q_fmt(x)   (Int32)(x*((Int32)1<<R_SHIFT) + (x>=0?0.5F:-0.5F))
+
+const Int32 log_table[9] =
+{
+    Q_fmt(-0.00879832091331F),  Q_fmt(0.12022974263833F),
+    Q_fmt(-0.72883958314294F),  Q_fmt(2.57909824242332F),
+    Q_fmt(-5.90041216630330F),  Q_fmt(9.15023342527264F),
+    Q_fmt(-9.90616619500413F),  Q_fmt(8.11228968755409F),
+    Q_fmt(-3.41763474309898F)
+};
+
+
+/*----------------------------------------------------------------------------
+; EXTERNAL FUNCTION REFERENCES
+; Declare functions defined elsewhere and referenced in this module
+----------------------------------------------------------------------------*/
+
+/*----------------------------------------------------------------------------
+; EXTERNAL GLOBAL STORE/BUFFER/POINTER REFERENCES
+; Declare variables used in this module but defined elsewhere
+----------------------------------------------------------------------------*/
+
+/*----------------------------------------------------------------------------
+; FUNCTION CODE
+----------------------------------------------------------------------------*/
+
+
+
+Int32 pv_log2(Int32 z)
+{
+    const Int32 *pt_table = log_table;
+    Int32 y;
+    Int32 i;
+
+    Int32 int_log2 = 0;
+
+    if (z > Q_fmt(2.0f))
+    {
+        while (z > Q_fmt(2.0f))
+        {
+            z >>= 1;
+            int_log2++;
+        }
+    }
+    else if (z < Q_fmt(1.0f))
+    {
+        {
+            while (z < Q_fmt(1.0f))
+            {
+                z <<= 1;
+                int_log2--;
+            }
+        }
+    }
+
+    /*
+     *  at this point, input limited to 1<x<2
+     */
+
+    if (z != Q_fmt(1.0f))
+    {
+        y  = fxp_mul32_Q20(*(pt_table++), z);
+
+        for (i = 7; i != 0; i--)
+        {
+            y += *(pt_table++);
+            y  = fxp_mul32_Q20(y, z);
+        }
+
+        y += *(pt_table++);
+    }
+    else
+    {
+        y = 0;
+    }
+
+
+    return (y + (int_log2 << 20));         /* Q20 */
+}
+
+
+#endif
+