Initial check in of AMR (NB and WB) decoders based on PV source code.

1 files changed, 270 insertions, 0 deletions

diff --git a/media/libstagefright/codecs/amrnb/common/src/inv_sqrt.cpp b/media/libstagefright/codecs/amrnb/common/src/inv_sqrt.cpp
new file mode 100644
index 0000000..83f4d0c
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+++ b/media/libstagefright/codecs/amrnb/common/src/inv_sqrt.cpp
@@ -0,0 +1,270 @@
+/* ------------------------------------------------------------------
+ * 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.
+ * -------------------------------------------------------------------
+ */
+/****************************************************************************************
+Portions of this file are derived from the following 3GPP standard:
+
+    3GPP TS 26.073
+    ANSI-C code for the Adaptive Multi-Rate (AMR) speech codec
+    Available from http://www.3gpp.org
+
+(C) 2004, 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TTA, TTC)
+Permission to distribute, modify and use this file under the standard license
+terms listed above has been obtained from the copyright holder.
+****************************************************************************************/
+/*
+ Pathname: ./audio/gsm-amr/c/src/inv_sqrt.c
+
+------------------------------------------------------------------------------
+ REVISION HISTORY
+
+ Description: Put file into template.
+
+ Description: Synchronized file with UMTS version 3.2.0. Updated coding
+              template. Removed unnecessary include files.
+
+ Description: Replaced basic_op.h with the header files of the math functions
+              used in the file.
+
+ Description: Made the following changes per comments from Phase 2/3 review:
+              1. Defined one local variable per line.
+              2. Used "&=", ">>=", and "+=" in the code.
+
+ Description: Updated template. Changed function interface to pass in a
+              pointer to overflow flag into the function instead of using a
+              global flag.
+
+ Description: Removed inclusion of inv_sqrt.tab file. Changed array name
+              from "table" to "inv_sqrt_tbl"
+
+ Description: Removed math operations that were not needed as functions,
+             this because the numbers themselves will not saturate the
+             operators, so there is not need to check for saturation.
+
+ Description: Updated copyrigth year, according to code review comments.
+
+ Description:  Replaced "int" and/or "char" with defined types.
+               Added proper casting (Word32) to some left shifting operations
+
+ Who:                           Date:
+ Description:
+
+------------------------------------------------------------------------------
+*/
+
+/*----------------------------------------------------------------------------
+; INCLUDES
+----------------------------------------------------------------------------*/
+#include    "inv_sqrt.h"
+#include    "typedef.h"
+#include    "basic_op.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
+----------------------------------------------------------------------------*/
+
+
+/*
+------------------------------------------------------------------------------
+ FUNCTION NAME: Inv_sqrt
+------------------------------------------------------------------------------
+ INPUT AND OUTPUT DEFINITIONS
+
+ Inputs:
+    L_x = input value (Word32)
+    pOverflow = pointer to overflow flag
+
+ Outputs:
+    pOverflow -> if the Inv_sqrt operation resulted in an overflow.
+
+ Returns:
+    L_y = inverse squareroot of L_x (Word32)
+
+ Global Variables Used:
+    None.
+
+ Local Variables Needed:
+    None.
+
+------------------------------------------------------------------------------
+ FUNCTION DESCRIPTION
+
+ This function computes 1/sqrt(L_x), where L_x is positive.
+ If L_x is negative or zero, the result is 1 (3fff ffff).
+
+ The function 1/sqrt(L_x) is approximated by a table and linear
+ interpolation. The inverse square root is computed using the
+ following steps:
+    1- Normalization of L_x.
+    2- If (30-exponent) is even then shift right once.
+    3- exponent = (30-exponent)/2  +1
+    4- i = bit25-b31 of L_x;  16<=i<=63  because of normalization.
+    5- a = bit10-b24
+    6- i -=16
+    7- L_y = table[i]<<16 - (table[i] - table[i+1]) * a * 2
+    8- L_y >>= exponent
+
+------------------------------------------------------------------------------
+ REQUIREMENTS
+
+ None.
+
+------------------------------------------------------------------------------
+ REFERENCES
+
+ inv_sqrt.c, UMTS GSM AMR speech codec, R99 - Version 3.2.0, March 2, 2001
+
+------------------------------------------------------------------------------
+ PSEUDO-CODE
+
+Word32 Inv_sqrt (       // (o) : output value
+    Word32 L_x          // (i) : input value
+)
+{
+    Word16 exp, i, a, tmp;
+    Word32 L_y;
+
+* The reference ETSI code uses a global Overflow flag. In the actual
+* implementation a pointer to the overflow flag is passed into the function.
+* This pointer is in turn passed into the basic math functions such as add(),
+* L_shl(), L_shr(), sub() called by this module.
+
+    if (L_x <= (Word32) 0)
+        return ((Word32) 0x3fffffffL);
+
+    exp = norm_l (L_x);
+    L_x = L_shl (L_x, exp);     // L_x is normalize
+
+    exp = sub (30, exp);
+
+    if ((exp & 1) == 0)         // If exponent even -> shift right
+    {
+        L_x = L_shr (L_x, 1);
+    }
+    exp = shr (exp, 1);
+    exp = add (exp, 1);
+
+    L_x = L_shr (L_x, 9);
+    i = extract_h (L_x);        // Extract b25-b31
+    L_x = L_shr (L_x, 1);
+    a = extract_l (L_x);        // Extract b10-b24
+    a = a & (Word16) 0x7fff;
+
+    i = sub (i, 16);
+
+    L_y = L_deposit_h (table[i]);       // table[i] << 16
+    tmp = sub (table[i], table[i + 1]); // table[i] - table[i+1])
+    L_y = L_msu (L_y, tmp, a);  // L_y -=  tmp*a*2
+
+    L_y = L_shr (L_y, exp);     // denormalization
+
+    return (L_y);
+}
+
+------------------------------------------------------------------------------
+ RESOURCES USED [optional]
+
+ When the code is written for a specific target processor the
+ the resources used should be documented below.
+
+ HEAP MEMORY USED: x bytes
+
+ STACK MEMORY USED: x bytes
+
+ CLOCK CYCLES: (cycle count equation for this function) + (variable
+                used to represent cycle count for each subroutine
+                called)
+     where: (cycle count variable) = cycle count for [subroutine
+                                     name]
+
+------------------------------------------------------------------------------
+ CAUTION [optional]
+ [State any special notes, constraints or cautions for users of this function]
+
+------------------------------------------------------------------------------
+*/
+
+Word32 Inv_sqrt(        /* (o) : output value   */
+    Word32 L_x,         /* (i) : input value    */
+    Flag   * pOverflow  /* (i) : pointer to overflow flag */
+)
+{
+    Word16 exp;
+    Word16 i;
+    Word16 a;
+    Word16 tmp;
+    Word32 L_y;
+    OSCL_UNUSED_ARG(pOverflow);
+
+    if (L_x <= (Word32) 0)
+    {
+        return ((Word32) 0x3fffffffL);
+    }
+
+    exp = norm_l(L_x);
+    L_x <<= exp;         /* L_x is normalize */
+
+    exp = 30 - exp;
+
+    if ((exp & 1) == 0)             /* If exponent even -> shift right */
+    {
+        L_x >>= 1;
+    }
+    exp >>= 1;
+    exp += 1;
+
+    L_x >>= 9;
+    i = (Word16)(L_x >> 16);        /* Extract b25-b31 */
+    a = (Word16)(L_x >> 1);         /* Extract b10-b24 */
+    a &= (Word16) 0x7fff;
+
+    i -= 16;
+
+    L_y = (Word32)inv_sqrt_tbl[i] << 16;    /* inv_sqrt_tbl[i] << 16    */
+
+    /* inv_sqrt_tbl[i] - inv_sqrt_tbl[i+1])  */
+    tmp =  inv_sqrt_tbl[i] - inv_sqrt_tbl[i + 1];
+    /* always a positive number less than 200 */
+
+    L_y -= ((Word32)tmp * a) << 1;        /* L_y -=  tmp*a*2         */
+    /* always a positive minus a small negative number */
+
+    L_y >>= exp;                /* denormalization, exp always 0< exp < 31 */
+
+    return (L_y);
+}
+