www.pudn.com > T-REC-G.722.1-200505-I!!SOFT-ZST-E.zip > dct4_a.c
/*********************************************************************************
**
** ITU-T 7/14kHz Audio Candidate (G.722.1 Annex C) Source Code
**
** © 2004 Polycom, Inc.
**
** All rights reserved.
**
*********************************************************************************/
/*********************************************************************************
* Filename: dct_type_iv_a.c
*
* Purpose: Discrete Cosine Transform, Type IV used for MLT
*
* The basis functions are
*
* cos(PI*(t+0.5)*(k+0.5)/block_length)
*
* for time t and basis function number k. Due to the symmetry of the expression
* in t and k, it is clear that the forward and inverse transforms are the same.
*
*********************************************************************************/
/*********************************************************************************
Include files
*********************************************************************************/
#include "defs.h"
#include "count.h"
#include "dct4_a.h"
/*********************************************************************************
External variable declarations
*********************************************************************************/
extern Word16 anal_bias[DCT_LENGTH];
extern Word16 dct_core_a[DCT_LENGTH_DIV_32][DCT_LENGTH_DIV_32];
extern cos_msin_t a_cos_msin_2 [DCT_LENGTH_DIV_32];
extern cos_msin_t a_cos_msin_4 [DCT_LENGTH_DIV_16];
extern cos_msin_t a_cos_msin_8 [DCT_LENGTH_DIV_8];
extern cos_msin_t a_cos_msin_16[DCT_LENGTH_DIV_4];
extern cos_msin_t a_cos_msin_32[DCT_LENGTH_DIV_2];
extern cos_msin_t a_cos_msin_64[DCT_LENGTH];
extern cos_msin_t *a_cos_msin_table[];
/*********************************************************************************
Function: dct_type_iv_a
Syntax: void dct_type_iv_a (input, output, dct_length)
Word16 input[], output[], dct_length;
Description: Discrete Cosine Transform, Type IV used for MLT
Design Notes:
WMOPS: | 24kbit | 32kbit
-------|--------------|----------------
AVG | 1.14 | 1.14
-------|--------------|----------------
MAX | 1.14 | 1.14
-------|--------------|----------------
14kHz | 24kbit | 32kbit | 48kbit
-------|--------------|----------------|----------------
AVG | 2.57 | 2.57 | 2.57
-------|--------------|----------------|----------------
MAX | 2.57 | 2.57 | 2.57
-------|--------------|----------------|----------------
*********************************************************************************/
void dct_type_iv_a (Word16 *input,Word16 *output,Word16 dct_length)
{
Word16 buffer_a[MAX_DCT_LENGTH], buffer_b[MAX_DCT_LENGTH], buffer_c[MAX_DCT_LENGTH];
Word16 *in_ptr, *in_ptr_low, *in_ptr_high, *next_in_base;
Word16 *out_ptr_low, *out_ptr_high, *next_out_base;
Word16 *out_buffer, *in_buffer, *buffer_swap;
Word16 in_val_low, in_val_high;
Word16 out_val_low, out_val_high;
Word16 in_low_even, in_low_odd;
Word16 in_high_even, in_high_odd;
Word16 out_low_even, out_low_odd;
Word16 out_high_even, out_high_odd;
Word16 *pair_ptr;
Word16 cos_even, cos_odd, msin_even, msin_odd;
Word16 neg_cos_odd;
Word16 neg_msin_even;
Word32 sum;
Word16 set_span, set_count, set_count_log, pairs_left, sets_left;
Word16 i,k;
Word16 index;
cos_msin_t **table_ptr_ptr, *cos_msin_ptr;
Word16 temp;
Word32 acca;
Word16 dct_length_log;
/*++++++++++++++++++++++++++++++++++++++++++++++++++++++*/
/* Do the sum/difference butterflies, the first part of */
/* converting one N-point transform into N/2 two-point */
/* transforms, where N = 1 << DCT_LENGTH_LOG. = 64/128 */
/*++++++++++++++++++++++++++++++++++++++++++++++++++++++*/
test();
if (dct_length==DCT_LENGTH)
{
dct_length_log = DCT_LENGTH_LOG;
/* Add bias offsets */
for (i=0;i0;sets_left--)
{
/*||||||||||||||||||||||||||||||||||||||||||||*/
/* Set up output pointers for the current set */
/*||||||||||||||||||||||||||||||||||||||||||||*/
out_ptr_low = next_out_base;
next_out_base = next_out_base + set_span;
out_ptr_high = next_out_base;
/*||||||||||||||||||||||||||||||||||||||||||||||||||*/
/* Loop over all the butterflies in the current set */
/*||||||||||||||||||||||||||||||||||||||||||||||||||*/
do
{
in_val_low = *in_ptr++;
in_val_high = *in_ptr++;
acca = L_add(in_val_low,in_val_high);
acca = L_shr(acca,1);
out_val_low = extract_l(acca);
acca = L_sub(in_val_low,in_val_high);
acca = L_shr(acca,1);
out_val_high = extract_l(acca);
*out_ptr_low++ = out_val_low;
*--out_ptr_high = out_val_high;
test();
} while (out_ptr_low < out_ptr_high);
} /* End of loop over sets of the current size */
/*============================================================*/
/* Decide which buffers to use as input and output next time. */
/* Except for the first time (when the input buffer is the */
/* subroutine input) we just alternate the local buffers. */
/*============================================================*/
in_buffer = out_buffer;
move16();
if (out_buffer == buffer_a)
out_buffer = buffer_b;
else
out_buffer = buffer_a;
index = add(index,1);
} /* End of loop over set sizes */
/*++++++++++++++++++++++++++++++++*/
/* Do N/2 two-point transforms, */
/* where N = 1 << DCT_LENGTH_LOG */
/*++++++++++++++++++++++++++++++++*/
pair_ptr = in_buffer;
move16();
buffer_swap = buffer_c;
move16();
temp = sub(dct_length_log,1);
temp = shl(1,temp);
for (pairs_left=temp; pairs_left > 0; pairs_left--)
{
for ( k=0; k= 0; set_count_log--)
{
/*===========================================================*/
/* Initialization for the loop over sets at the current size */
/*===========================================================*/
/* set_span = 1 << (DCT_LENGTH_LOG - set_count_log); */
set_span = shr(dct_length,set_count_log);
set_count = shl(1,set_count_log);
next_in_base = in_buffer;
move16();
test();
if (set_count_log == 0)
{
next_out_base = output;
}
else
{
next_out_base = out_buffer;
}
/*=====================================*/
/* Loop over all the sets of this size */
/*=====================================*/
for (sets_left = set_count; sets_left > 0;sets_left--)
{
/*|||||||||||||||||||||||||||||||||||||||||*/
/* Set up the pointers for the current set */
/*|||||||||||||||||||||||||||||||||||||||||*/
in_ptr_low = next_in_base;
move16();
temp = shr(set_span,1);
/* address arithmetic */
in_ptr_high = in_ptr_low + temp;
next_in_base += set_span;
out_ptr_low = next_out_base;
next_out_base += set_span;
out_ptr_high = next_out_base;
cos_msin_ptr = *table_ptr_ptr;
/*||||||||||||||||||||||||||||||||||||||||||||||||||||||*/
/* Loop over all the butterfly pairs in the current set */
/*||||||||||||||||||||||||||||||||||||||||||||||||||||||*/
do
{
/* address arithmetic */
in_low_even = *in_ptr_low++;
in_low_odd = *in_ptr_low++;
in_high_even = *in_ptr_high++;
in_high_odd = *in_ptr_high++;
cos_even = cos_msin_ptr[0].cosine;
move16();
msin_even = cos_msin_ptr[0].minus_sine;
move16();
cos_odd = cos_msin_ptr[1].cosine;
move16();
msin_odd = cos_msin_ptr[1].minus_sine;
move16();
cos_msin_ptr += 2;
sum = 0L;
sum=L_mac(sum,cos_even,in_low_even);
neg_msin_even = negate(msin_even);
sum=L_mac(sum,neg_msin_even,in_high_even);
out_low_even = round(sum);
sum = 0L;
sum=L_mac(sum,msin_even,in_low_even);
sum=L_mac(sum,cos_even,in_high_even);
out_high_even= round(sum);
sum = 0L;
sum=L_mac(sum,cos_odd,in_low_odd);
sum=L_mac(sum,msin_odd,in_high_odd);
out_low_odd= round(sum);
sum = 0L;
sum=L_mac(sum,msin_odd,in_low_odd);
neg_cos_odd = negate(cos_odd);
sum=L_mac(sum,neg_cos_odd,in_high_odd);
out_high_odd= round(sum);
*out_ptr_low++ = out_low_even;
*--out_ptr_high = out_high_even;
*out_ptr_low++ = out_low_odd;
*--out_ptr_high = out_high_odd;
test();
} while (out_ptr_low < out_ptr_high);
} /* End of loop over sets of the current size */
/*=============================================*/
/* Swap input and output buffers for next time */
/*=============================================*/
buffer_swap = in_buffer;
in_buffer = out_buffer;
out_buffer = buffer_swap;
table_ptr_ptr++;
}
}