FreeRDP/libfreerdp-codec/rfx_dwt.c

195 lines
5.2 KiB
C

/**
* FreeRDP: A Remote Desktop Protocol client.
* RemoteFX Codec Library - DWT
*
* Copyright 2011 Vic Lee
*
* 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.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "rfx_dwt.h"
static void rfx_dwt_2d_decode_block(sint16* buffer, sint16* idwt, int subband_width)
{
sint16 *dst, *l, *h;
sint16 *l_dst, *h_dst;
sint16 *hl, *lh, *hh, *ll;
int total_width;
int x, y;
int n;
total_width = subband_width << 1;
/* Inverse DWT in horizontal direction, results in 2 sub-bands in L, H order in tmp buffer idwt. */
/* The 4 sub-bands are stored in HL(0), LH(1), HH(2), LL(3) order. */
/* The lower part L uses LL(3) and HL(0). */
/* The higher part H uses LH(1) and HH(2). */
ll = buffer + subband_width * subband_width * 3;
hl = buffer;
l_dst = idwt;
lh = buffer + subband_width * subband_width;
hh = buffer + subband_width * subband_width * 2;
h_dst = idwt + subband_width * subband_width * 2;
for (y = 0; y < subband_width; y++)
{
/* Even coefficients */
l_dst[0] = ll[0] - ((hl[0] + hl[0] + 1) >> 1);
h_dst[0] = lh[0] - ((hh[0] + hh[0] + 1) >> 1);
for (n = 1; n < subband_width; n++)
{
x = n << 1;
l_dst[x] = ll[n] - ((hl[n-1] + hl[n] + 1) >> 1);
h_dst[x] = lh[n] - ((hh[n-1] + hh[n] + 1) >> 1);
}
/* Odd coefficients */
for (n = 0; n < subband_width-1; n++)
{
x = n << 1;
l_dst[x + 1] = (hl[n] << 1) + ((l_dst[x] + l_dst[x + 2]) >> 1);
h_dst[x + 1] = (hh[n] << 1) + ((h_dst[x] + h_dst[x + 2]) >> 1);
}
x = n << 1;
l_dst[x + 1] = (hl[n] << 1) + (l_dst[x]);
h_dst[x + 1] = (hh[n] << 1) + (h_dst[x]);
ll += subband_width;
hl += subband_width;
l_dst += total_width;
lh += subband_width;
hh += subband_width;
h_dst += total_width;
}
/* Inverse DWT in vertical direction, results are stored in original buffer. */
for (x = 0; x < total_width; x++)
{
/* Even coefficients */
for (n = 0; n < subband_width; n++)
{
y = n << 1;
dst = buffer + y * total_width + x;
l = idwt + n * total_width + x;
h = l + subband_width * total_width;
dst[0] = *l - (((n > 0 ? *(h - total_width) : *h) + (*h) + 1) >> 1);
}
/* Odd coefficients */
for (n = 0; n < subband_width; n++)
{
y = n << 1;
dst = buffer + y * total_width + x;
l = idwt + n * total_width + x;
h = l + subband_width * total_width;
dst[total_width] = (*h << 1) + ((dst[0] + dst[n < subband_width - 1 ? 2 * total_width : 0]) >> 1);
}
}
}
void rfx_dwt_2d_decode(sint16* buffer, sint16* dwt_buffer)
{
rfx_dwt_2d_decode_block(buffer + 3840, dwt_buffer, 8);
rfx_dwt_2d_decode_block(buffer + 3072, dwt_buffer, 16);
rfx_dwt_2d_decode_block(buffer, dwt_buffer, 32);
}
static void rfx_dwt_2d_encode_block(sint16* buffer, sint16* dwt, int subband_width)
{
sint16 *src, *l, *h;
sint16 *l_src, *h_src;
sint16 *hl, *lh, *hh, *ll;
int total_width;
int x, y;
int n;
total_width = subband_width << 1;
/* DWT in vertical direction, results in 2 sub-bands in L, H order in tmp buffer dwt. */
for (x = 0; x < total_width; x++)
{
for (n = 0; n < subband_width; n++)
{
y = n << 1;
l = dwt + n * total_width + x;
h = l + subband_width * total_width;
src = buffer + y * total_width + x;
/* H */
*h = (src[total_width] - ((src[0] + src[n < subband_width - 1 ? 2 * total_width : 0]) >> 1)) >> 1;
/* L */
*l = src[0] + (n == 0 ? *h : (*(h - total_width) + *h) >> 1);
}
}
/* DWT in horizontal direction, results in 4 sub-bands in HL(0), LH(1), HH(2), LL(3) order, stored in original buffer. */
/* The lower part L generates LL(3) and HL(0). */
/* The higher part H generates LH(1) and HH(2). */
ll = buffer + subband_width * subband_width * 3;
hl = buffer;
l_src = dwt;
lh = buffer + subband_width * subband_width;
hh = buffer + subband_width * subband_width * 2;
h_src = dwt + subband_width * subband_width * 2;
for (y = 0; y < subband_width; y++)
{
/* L */
for (n = 0; n < subband_width; n++)
{
x = n << 1;
/* HL */
hl[n] = (l_src[x + 1] - ((l_src[x] + l_src[n < subband_width - 1 ? x + 2 : x]) >> 1)) >> 1;
/* LL */
ll[n] = l_src[x] + (n == 0 ? hl[n] : (hl[n - 1] + hl[n]) >> 1);
}
/* H */
for (n = 0; n < subband_width; n++)
{
x = n << 1;
/* HH */
hh[n] = (h_src[x + 1] - ((h_src[x] + h_src[n < subband_width - 1 ? x + 2 : x]) >> 1)) >> 1;
/* LH */
lh[n] = h_src[x] + (n == 0 ? hh[n] : (hh[n - 1] + hh[n]) >> 1);
}
ll += subband_width;
hl += subband_width;
l_src += total_width;
lh += subband_width;
hh += subband_width;
h_src += total_width;
}
}
void rfx_dwt_2d_encode(sint16* buffer, sint16* dwt_buffer)
{
rfx_dwt_2d_encode_block(buffer, dwt_buffer, 32);
rfx_dwt_2d_encode_block(buffer + 3072, dwt_buffer, 16);
rfx_dwt_2d_encode_block(buffer + 3840, dwt_buffer, 8);
}