You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
145 lines
3.7 KiB
C++
145 lines
3.7 KiB
C++
![]()
11 months ago
|
/*
|
||
|
* Project 25 IMBE Encoder/Decoder Fixed-Point implementation
|
||
|
* Developed by Pavel Yazev E-mail: pyazev@gmail.com
|
||
|
* Version 1.0 (c) Copyright 2009
|
||
|
*
|
||
|
* This is free software; you can redistribute it and/or modify it
|
||
|
* under the terms of the GNU General Public License as published by
|
||
|
* the Free Software Foundation; either version 3, or (at your option)
|
||
|
* any later version.
|
||
|
*
|
||
|
* The software is distributed in the hope that it will be useful, but
|
||
|
* WITHOUT ANY WARRANTY; without even the implied warranty of
|
||
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
|
||
|
* See the GNU General Public License for more details.
|
||
|
*
|
||
|
* You should have received a copy of the GNU General Public License
|
||
|
* along with this; see the file COPYING. If not, write to the Free
|
||
|
* Software Foundation, Inc., 51 Franklin Street, Boston, MA
|
||
|
* 02110-1301, USA.
|
||
|
*/
|
||
|
|
||
|
|
||
|
#include "typedef.h"
|
||
|
#include "basic_op.h"
|
||
|
#include "qnt_sub.h"
|
||
|
|
||
|
|
||
|
//-----------------------------------------------------------------------------
|
||
|
// PURPOSE:
|
||
|
// Dequantize by quantizer step size
|
||
|
//
|
||
|
//
|
||
|
// INPUT:
|
||
|
// qval - quantized value
|
||
|
// step_size - step size used to quantize in unsigned Q0.16 format
|
||
|
// bit_num - the number of bits
|
||
|
//
|
||
|
// OUTPUT:
|
||
|
// None
|
||
|
//
|
||
|
// RETURN:
|
||
|
// Quantized Value in signed (bit_num).16 format
|
||
|
//
|
||
|
//-----------------------------------------------------------------------------
|
||
|
Word32 deqnt_by_step(Word16 qval, UWord16 step_size, Word16 bit_num)
|
||
|
{
|
||
|
Word32 res;
|
||
|
|
||
|
if(bit_num == 0)
|
||
|
return (Word32)0;
|
||
|
|
||
|
res = (Word32)step_size * (qval - (1 << (bit_num - 1)));
|
||
|
res = L_add(res, ((Word32)step_size * CNST_0_5_Q0_16) >> 16);
|
||
|
|
||
|
return res;
|
||
|
}
|
||
|
|
||
|
|
||
|
|
||
|
//-----------------------------------------------------------------------------
|
||
|
// PURPOSE:
|
||
|
// Quantize by quantizer step size
|
||
|
//
|
||
|
//
|
||
|
// INPUT:
|
||
|
// val - value to be quantized in Q5.10 format
|
||
|
// step_size - step size used to quantize in unsigned Q0.16 format
|
||
|
// bit_num - the number of bits
|
||
|
//
|
||
|
// OUTPUT:
|
||
|
// None
|
||
|
//
|
||
|
// RETURN:
|
||
|
// Quantized Value in integer
|
||
|
//
|
||
|
//-----------------------------------------------------------------------------
|
||
|
Word16 qnt_by_step(Word16 val, UWord16 step_size, Word16 bit_num)
|
||
|
{
|
||
|
Word16 index, min_val, max_val;
|
||
|
Word16 q_index, shift, tmp;
|
||
|
|
||
|
shift = norm_s(step_size);
|
||
|
|
||
|
tmp = div_s(0x4000, shl(step_size, shift)); // Remark: To get result in Qxx.16 format it is necessary left shift tmp by (shift + 3)
|
||
|
q_index = shr_r(mult(val, tmp), sub(9, shift)); // q_index here is rounded to the nearest integer
|
||
|
|
||
|
max_val = 1 << (bit_num - 1);
|
||
|
min_val = negate(max_val);
|
||
|
|
||
|
if(q_index < min_val)
|
||
|
index = 0;
|
||
|
else if(q_index >= max_val)
|
||
|
index = (1 << bit_num) - 1;
|
||
|
else
|
||
|
index = max_val + q_index;
|
||
|
|
||
|
return index;
|
||
|
}
|
||
|
|
||
|
//-----------------------------------------------------------------------------
|
||
|
// PURPOSE:
|
||
|
// Quantize by table
|
||
|
//
|
||
|
//
|
||
|
// INPUT:
|
||
|
// val - value to be quantized
|
||
|
// q_tbl - pointer to table
|
||
|
// q_tbl_size - size of table
|
||
|
//
|
||
|
// OUTPUT:
|
||
|
// None
|
||
|
//
|
||
|
// RETURN:
|
||
|
// Quantized Value in integer
|
||
|
//
|
||
|
//-----------------------------------------------------------------------------
|
||
|
Word16 tbl_quant(Word16 val, Word16 *q_tbl, Word16 q_tbl_size)
|
||
|
{
|
||
|
Word16 min_index, max_index, index;
|
||
|
|
||
|
min_index = 0;
|
||
|
max_index = q_tbl_size - 1;
|
||
|
|
||
|
if(val >= q_tbl[max_index])
|
||
|
return max_index;
|
||
|
|
||
|
if(val <= q_tbl[min_index])
|
||
|
return min_index;
|
||
|
|
||
|
while(max_index - min_index != 1)
|
||
|
{
|
||
|
index = min_index + ((max_index - min_index) >> 1);
|
||
|
|
||
|
if(q_tbl[index] > val)
|
||
|
max_index = index;
|
||
|
else
|
||
|
min_index = index;
|
||
|
}
|
||
|
|
||
|
if(q_tbl[max_index] - val <= val - q_tbl[min_index])
|
||
|
return max_index;
|
||
|
else
|
||
|
return min_index;
|
||
|
}
|