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ffmpeg/libavcodec/imgresample.c

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/*
* High quality image resampling with polyphase filters
* Copyright (c) 2001 Fabrice Bellard.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
/**
* @file imgresample.c
* High quality image resampling with polyphase filters .
*/
#include "avcodec.h"
#include "dsputil.h"
#ifdef USE_FASTMEMCPY
#include "fastmemcpy.h"
#endif
#define NB_COMPONENTS 3
#define PHASE_BITS 4
#define NB_PHASES (1 << PHASE_BITS)
#define NB_TAPS 4
#define FCENTER 1 /* index of the center of the filter */
//#define TEST 1 /* Test it */
#define POS_FRAC_BITS 16
#define POS_FRAC (1 << POS_FRAC_BITS)
/* 6 bits precision is needed for MMX */
#define FILTER_BITS 8
#define LINE_BUF_HEIGHT (NB_TAPS * 4)
struct ImgReSampleContext {
int iwidth, iheight, owidth, oheight, topBand, bottomBand, leftBand, rightBand;
int h_incr, v_incr;
int16_t h_filters[NB_PHASES][NB_TAPS] __align8; /* horizontal filters */
int16_t v_filters[NB_PHASES][NB_TAPS] __align8; /* vertical filters */
uint8_t *line_buf;
};
static inline int get_phase(int pos)
{
return ((pos) >> (POS_FRAC_BITS - PHASE_BITS)) & ((1 << PHASE_BITS) - 1);
}
/* This function must be optimized */
static void h_resample_fast(uint8_t *dst, int dst_width, uint8_t *src, int src_width,
int src_start, int src_incr, int16_t *filters)
{
int src_pos, phase, sum, i;
uint8_t *s;
int16_t *filter;
src_pos = src_start;
for(i=0;i<dst_width;i++) {
#ifdef TEST
/* test */
if ((src_pos >> POS_FRAC_BITS) < 0 ||
(src_pos >> POS_FRAC_BITS) > (src_width - NB_TAPS))
av_abort();
#endif
s = src + (src_pos >> POS_FRAC_BITS);
phase = get_phase(src_pos);
filter = filters + phase * NB_TAPS;
#if NB_TAPS == 4
sum = s[0] * filter[0] +
s[1] * filter[1] +
s[2] * filter[2] +
s[3] * filter[3];
#else
{
int j;
sum = 0;
for(j=0;j<NB_TAPS;j++)
sum += s[j] * filter[j];
}
#endif
sum = sum >> FILTER_BITS;
if (sum < 0)
sum = 0;
else if (sum > 255)
sum = 255;
dst[0] = sum;
src_pos += src_incr;
dst++;
}
}
/* This function must be optimized */
static void v_resample(uint8_t *dst, int dst_width, uint8_t *src, int wrap,
int16_t *filter)
{
int sum, i;
uint8_t *s;
s = src;
for(i=0;i<dst_width;i++) {
#if NB_TAPS == 4
sum = s[0 * wrap] * filter[0] +
s[1 * wrap] * filter[1] +
s[2 * wrap] * filter[2] +
s[3 * wrap] * filter[3];
#else
{
int j;
uint8_t *s1 = s;
sum = 0;
for(j=0;j<NB_TAPS;j++) {
sum += s1[0] * filter[j];
s1 += wrap;
}
}
#endif
sum = sum >> FILTER_BITS;
if (sum < 0)
sum = 0;
else if (sum > 255)
sum = 255;
dst[0] = sum;
dst++;
s++;
}
}
#ifdef HAVE_MMX
#include "i386/mmx.h"
#define FILTER4(reg) \
{\
s = src + (src_pos >> POS_FRAC_BITS);\
phase = get_phase(src_pos);\
filter = filters + phase * NB_TAPS;\
movq_m2r(*s, reg);\
punpcklbw_r2r(mm7, reg);\
movq_m2r(*filter, mm6);\
pmaddwd_r2r(reg, mm6);\
movq_r2r(mm6, reg);\
psrlq_i2r(32, reg);\
paddd_r2r(mm6, reg);\
psrad_i2r(FILTER_BITS, reg);\
src_pos += src_incr;\
}
#define DUMP(reg) movq_r2m(reg, tmp); printf(#reg "=%016Lx\n", tmp.uq);
/* XXX: do four pixels at a time */
static void h_resample_fast4_mmx(uint8_t *dst, int dst_width, uint8_t *src, int src_width,
int src_start, int src_incr, int16_t *filters)
{
int src_pos, phase;
uint8_t *s;
int16_t *filter;
mmx_t tmp;
src_pos = src_start;
pxor_r2r(mm7, mm7);
while (dst_width >= 4) {
FILTER4(mm0);
FILTER4(mm1);
FILTER4(mm2);
FILTER4(mm3);
packuswb_r2r(mm7, mm0);
packuswb_r2r(mm7, mm1);
packuswb_r2r(mm7, mm3);
packuswb_r2r(mm7, mm2);
movq_r2m(mm0, tmp);
dst[0] = tmp.ub[0];
movq_r2m(mm1, tmp);
dst[1] = tmp.ub[0];
movq_r2m(mm2, tmp);
dst[2] = tmp.ub[0];
movq_r2m(mm3, tmp);
dst[3] = tmp.ub[0];
dst += 4;
dst_width -= 4;
}
while (dst_width > 0) {
FILTER4(mm0);
packuswb_r2r(mm7, mm0);
movq_r2m(mm0, tmp);
dst[0] = tmp.ub[0];
dst++;
dst_width--;
}
emms();
}
static void v_resample4_mmx(uint8_t *dst, int dst_width, uint8_t *src, int wrap,
int16_t *filter)
{
int sum, i, v;
uint8_t *s;
mmx_t tmp;
mmx_t coefs[4];
for(i=0;i<4;i++) {
v = filter[i];
coefs[i].uw[0] = v;
coefs[i].uw[1] = v;
coefs[i].uw[2] = v;
coefs[i].uw[3] = v;
}
pxor_r2r(mm7, mm7);
s = src;
while (dst_width >= 4) {
movq_m2r(s[0 * wrap], mm0);
punpcklbw_r2r(mm7, mm0);
movq_m2r(s[1 * wrap], mm1);
punpcklbw_r2r(mm7, mm1);
movq_m2r(s[2 * wrap], mm2);
punpcklbw_r2r(mm7, mm2);
movq_m2r(s[3 * wrap], mm3);
punpcklbw_r2r(mm7, mm3);
pmullw_m2r(coefs[0], mm0);
pmullw_m2r(coefs[1], mm1);
pmullw_m2r(coefs[2], mm2);
pmullw_m2r(coefs[3], mm3);
paddw_r2r(mm1, mm0);
paddw_r2r(mm3, mm2);
paddw_r2r(mm2, mm0);
psraw_i2r(FILTER_BITS, mm0);
packuswb_r2r(mm7, mm0);
movq_r2m(mm0, tmp);
*(uint32_t *)dst = tmp.ud[0];
dst += 4;
s += 4;
dst_width -= 4;
}
while (dst_width > 0) {
sum = s[0 * wrap] * filter[0] +
s[1 * wrap] * filter[1] +
s[2 * wrap] * filter[2] +
s[3 * wrap] * filter[3];
sum = sum >> FILTER_BITS;
if (sum < 0)
sum = 0;
else if (sum > 255)
sum = 255;
dst[0] = sum;
dst++;
s++;
dst_width--;
}
emms();
}
#endif
#ifdef HAVE_ALTIVEC
typedef union {
vector unsigned char v;
unsigned char c[16];
} vec_uc_t;
typedef union {
vector signed short v;
signed short s[8];
} vec_ss_t;
void v_resample16_altivec(uint8_t *dst, int dst_width, uint8_t *src, int wrap,
int16_t *filter)
{
int sum, i;
uint8_t *s;
vector unsigned char *tv, tmp, dstv, zero;
vec_ss_t srchv[4], srclv[4], fv[4];
vector signed short zeros, sumhv, sumlv;
s = src;
for(i=0;i<4;i++)
{
/*
The vec_madds later on does an implicit >>15 on the result.
Since FILTER_BITS is 8, and we have 15 bits of magnitude in
a signed short, we have just enough bits to pre-shift our
filter constants <<7 to compensate for vec_madds.
*/
fv[i].s[0] = filter[i] << (15-FILTER_BITS);
fv[i].v = vec_splat(fv[i].v, 0);
}
zero = vec_splat_u8(0);
zeros = vec_splat_s16(0);
/*
When we're resampling, we'd ideally like both our input buffers,
and output buffers to be 16-byte aligned, so we can do both aligned
reads and writes. Sadly we can't always have this at the moment, so
we opt for aligned writes, as unaligned writes have a huge overhead.
To do this, do enough scalar resamples to get dst 16-byte aligned.
*/
i = (-(int)dst) & 0xf;
while(i>0) {
sum = s[0 * wrap] * filter[0] +
s[1 * wrap] * filter[1] +
s[2 * wrap] * filter[2] +
s[3 * wrap] * filter[3];
sum = sum >> FILTER_BITS;
if (sum<0) sum = 0; else if (sum>255) sum=255;
dst[0] = sum;
dst++;
s++;
dst_width--;
i--;
}
/* Do our altivec resampling on 16 pixels at once. */
while(dst_width>=16) {
/*
Read 16 (potentially unaligned) bytes from each of
4 lines into 4 vectors, and split them into shorts.
Interleave the multipy/accumulate for the resample
filter with the loads to hide the 3 cycle latency
the vec_madds have.
*/
tv = (vector unsigned char *) &s[0 * wrap];
tmp = vec_perm(tv[0], tv[1], vec_lvsl(0, &s[i * wrap]));
srchv[0].v = (vector signed short) vec_mergeh(zero, tmp);
srclv[0].v = (vector signed short) vec_mergel(zero, tmp);
sumhv = vec_madds(srchv[0].v, fv[0].v, zeros);
sumlv = vec_madds(srclv[0].v, fv[0].v, zeros);
tv = (vector unsigned char *) &s[1 * wrap];
tmp = vec_perm(tv[0], tv[1], vec_lvsl(0, &s[1 * wrap]));
srchv[1].v = (vector signed short) vec_mergeh(zero, tmp);
srclv[1].v = (vector signed short) vec_mergel(zero, tmp);
sumhv = vec_madds(srchv[1].v, fv[1].v, sumhv);
sumlv = vec_madds(srclv[1].v, fv[1].v, sumlv);
tv = (vector unsigned char *) &s[2 * wrap];
tmp = vec_perm(tv[0], tv[1], vec_lvsl(0, &s[2 * wrap]));
srchv[2].v = (vector signed short) vec_mergeh(zero, tmp);
srclv[2].v = (vector signed short) vec_mergel(zero, tmp);
sumhv = vec_madds(srchv[2].v, fv[2].v, sumhv);
sumlv = vec_madds(srclv[2].v, fv[2].v, sumlv);
tv = (vector unsigned char *) &s[3 * wrap];
tmp = vec_perm(tv[0], tv[1], vec_lvsl(0, &s[3 * wrap]));
srchv[3].v = (vector signed short) vec_mergeh(zero, tmp);
srclv[3].v = (vector signed short) vec_mergel(zero, tmp);
sumhv = vec_madds(srchv[3].v, fv[3].v, sumhv);
sumlv = vec_madds(srclv[3].v, fv[3].v, sumlv);
/*
Pack the results into our destination vector,
and do an aligned write of that back to memory.
*/
dstv = vec_packsu(sumhv, sumlv) ;
vec_st(dstv, 0, (vector unsigned char *) dst);
dst+=16;
s+=16;
dst_width-=16;
}
/*
If there are any leftover pixels, resample them
with the slow scalar method.
*/
while(dst_width>0) {
sum = s[0 * wrap] * filter[0] +
s[1 * wrap] * filter[1] +
s[2 * wrap] * filter[2] +
s[3 * wrap] * filter[3];
sum = sum >> FILTER_BITS;
if (sum<0) sum = 0; else if (sum>255) sum=255;
dst[0] = sum;
dst++;
s++;
dst_width--;
}
}
#endif
/* slow version to handle limit cases. Does not need optimisation */
static void h_resample_slow(uint8_t *dst, int dst_width, uint8_t *src, int src_width,
int src_start, int src_incr, int16_t *filters)
{
int src_pos, phase, sum, j, v, i;
uint8_t *s, *src_end;
int16_t *filter;
src_end = src + src_width;
src_pos = src_start;
for(i=0;i<dst_width;i++) {
s = src + (src_pos >> POS_FRAC_BITS);
phase = get_phase(src_pos);
filter = filters + phase * NB_TAPS;
sum = 0;
for(j=0;j<NB_TAPS;j++) {
if (s < src)
v = src[0];
else if (s >= src_end)
v = src_end[-1];
else
v = s[0];
sum += v * filter[j];
s++;
}
sum = sum >> FILTER_BITS;
if (sum < 0)
sum = 0;
else if (sum > 255)
sum = 255;
dst[0] = sum;
src_pos += src_incr;
dst++;
}
}
static void h_resample(uint8_t *dst, int dst_width, uint8_t *src, int src_width,
int src_start, int src_incr, int16_t *filters)
{
int n, src_end;
if (src_start < 0) {
n = (0 - src_start + src_incr - 1) / src_incr;
h_resample_slow(dst, n, src, src_width, src_start, src_incr, filters);
dst += n;
dst_width -= n;
src_start += n * src_incr;
}
src_end = src_start + dst_width * src_incr;
if (src_end > ((src_width - NB_TAPS) << POS_FRAC_BITS)) {
n = (((src_width - NB_TAPS + 1) << POS_FRAC_BITS) - 1 - src_start) /
src_incr;
} else {
n = dst_width;
}
#ifdef HAVE_MMX
if ((mm_flags & MM_MMX) && NB_TAPS == 4)
h_resample_fast4_mmx(dst, n,
src, src_width, src_start, src_incr, filters);
else
#endif
h_resample_fast(dst, n,
src, src_width, src_start, src_incr, filters);
if (n < dst_width) {
dst += n;
dst_width -= n;
src_start += n * src_incr;
h_resample_slow(dst, dst_width,
src, src_width, src_start, src_incr, filters);
}
}
static void component_resample(ImgReSampleContext *s,
uint8_t *output, int owrap, int owidth, int oheight,
uint8_t *input, int iwrap, int iwidth, int iheight)
{
int src_y, src_y1, last_src_y, ring_y, phase_y, y1, y;
uint8_t *new_line, *src_line;
last_src_y = - FCENTER - 1;
/* position of the bottom of the filter in the source image */
src_y = (last_src_y + NB_TAPS) * POS_FRAC;
ring_y = NB_TAPS; /* position in ring buffer */
for(y=0;y<oheight;y++) {
/* apply horizontal filter on new lines from input if needed */
src_y1 = src_y >> POS_FRAC_BITS;
while (last_src_y < src_y1) {
if (++ring_y >= LINE_BUF_HEIGHT + NB_TAPS)
ring_y = NB_TAPS;
last_src_y++;
/* handle limit conditions : replicate line (slightly
inefficient because we filter multiple times) */
y1 = last_src_y;
if (y1 < 0) {
y1 = 0;
} else if (y1 >= iheight) {
y1 = iheight - 1;
}
src_line = input + y1 * iwrap;
new_line = s->line_buf + ring_y * owidth;
/* apply filter and handle limit cases correctly */
h_resample(new_line, owidth,
src_line, iwidth, - FCENTER * POS_FRAC, s->h_incr,
&s->h_filters[0][0]);
/* handle ring buffer wraping */
if (ring_y >= LINE_BUF_HEIGHT) {
memcpy(s->line_buf + (ring_y - LINE_BUF_HEIGHT) * owidth,
new_line, owidth);
}
}
/* apply vertical filter */
phase_y = get_phase(src_y);
#ifdef HAVE_MMX
/* desactivated MMX because loss of precision */
if ((mm_flags & MM_MMX) && NB_TAPS == 4 && 0)
v_resample4_mmx(output, owidth,
s->line_buf + (ring_y - NB_TAPS + 1) * owidth, owidth,
&s->v_filters[phase_y][0]);
else
#endif
#ifdef HAVE_ALTIVEC
if ((mm_flags & MM_ALTIVEC) && NB_TAPS == 4 && FILTER_BITS <= 6)
v_resample16_altivec(output, owidth,
s->line_buf + (ring_y - NB_TAPS + 1) * owidth, owidth,
&s->v_filters[phase_y][0]);
else
#endif
v_resample(output, owidth,
s->line_buf + (ring_y - NB_TAPS + 1) * owidth, owidth,
&s->v_filters[phase_y][0]);
src_y += s->v_incr;
output += owrap;
}
}
/* XXX: the following filter is quite naive, but it seems to suffice
for 4 taps */
static void build_filter(int16_t *filter, float factor)
{
int ph, i, v;
float x, y, tab[NB_TAPS], norm, mult;
/* if upsampling, only need to interpolate, no filter */
if (factor > 1.0)
factor = 1.0;
for(ph=0;ph<NB_PHASES;ph++) {
norm = 0;
for(i=0;i<NB_TAPS;i++) {
x = M_PI * ((float)(i - FCENTER) - (float)ph / NB_PHASES) * factor;
if (x == 0)
y = 1.0;
else
y = sin(x) / x;
tab[i] = y;
norm += y;
}
/* normalize so that an uniform color remains the same */
mult = (float)(1 << FILTER_BITS) / norm;
for(i=0;i<NB_TAPS;i++) {
v = (int)(tab[i] * mult);
filter[ph * NB_TAPS + i] = v;
}
}
}
ImgReSampleContext *img_resample_init(int owidth, int oheight,
int iwidth, int iheight)
{
return img_resample_full_init(owidth, oheight, iwidth, iheight, 0, 0, 0, 0);
}
ImgReSampleContext *img_resample_full_init(int owidth, int oheight,
int iwidth, int iheight,
int topBand, int bottomBand,
int leftBand, int rightBand)
{
ImgReSampleContext *s;
s = av_mallocz(sizeof(ImgReSampleContext));
if (!s)
return NULL;
s->line_buf = av_mallocz(owidth * (LINE_BUF_HEIGHT + NB_TAPS));
if (!s->line_buf)
goto fail;
s->owidth = owidth;
s->oheight = oheight;
s->iwidth = iwidth;
s->iheight = iheight;
s->topBand = topBand;
s->bottomBand = bottomBand;
s->leftBand = leftBand;
s->rightBand = rightBand;
s->h_incr = ((iwidth - leftBand - rightBand) * POS_FRAC) / owidth;
s->v_incr = ((iheight - topBand - bottomBand) * POS_FRAC) / oheight;
build_filter(&s->h_filters[0][0], (float) owidth / (float) (iwidth - leftBand - rightBand));
build_filter(&s->v_filters[0][0], (float) oheight / (float) (iheight - topBand - bottomBand));
return s;
fail:
av_free(s);
return NULL;
}
void img_resample(ImgReSampleContext *s,
AVPicture *output, AVPicture *input)
{
int i, shift;
for(i=0;i<3;i++) {
shift = (i == 0) ? 0 : 1;
component_resample(s, output->data[i], output->linesize[i],
s->owidth >> shift, s->oheight >> shift,
input->data[i] + (input->linesize[i] * (s->topBand >> shift)) + (s->leftBand >> shift),
input->linesize[i], ((s->iwidth - s->leftBand - s->rightBand) >> shift),
(s->iheight - s->topBand - s->bottomBand) >> shift);
}
}
void img_resample_close(ImgReSampleContext *s)
{
av_free(s->line_buf);
av_free(s);
}
#ifdef TEST
void *av_mallocz(int size)
{
void *ptr;
ptr = malloc(size);
memset(ptr, 0, size);
return ptr;
}
void av_free(void *ptr)
{
/* XXX: this test should not be needed on most libcs */
if (ptr)
free(ptr);
}
/* input */
#define XSIZE 256
#define YSIZE 256
uint8_t img[XSIZE * YSIZE];
/* output */
#define XSIZE1 512
#define YSIZE1 512
uint8_t img1[XSIZE1 * YSIZE1];
uint8_t img2[XSIZE1 * YSIZE1];
void save_pgm(const char *filename, uint8_t *img, int xsize, int ysize)
{
FILE *f;
f=fopen(filename,"w");
fprintf(f,"P5\n%d %d\n%d\n", xsize, ysize, 255);
fwrite(img,1, xsize * ysize,f);
fclose(f);
}
static void dump_filter(int16_t *filter)
{
int i, ph;
for(ph=0;ph<NB_PHASES;ph++) {
printf("%2d: ", ph);
for(i=0;i<NB_TAPS;i++) {
printf(" %5.2f", filter[ph * NB_TAPS + i] / 256.0);
}
printf("\n");
}
}
#ifdef HAVE_MMX
int mm_flags;
#endif
int main(int argc, char **argv)
{
int x, y, v, i, xsize, ysize;
ImgReSampleContext *s;
float fact, factors[] = { 1/2.0, 3.0/4.0, 1.0, 4.0/3.0, 16.0/9.0, 2.0 };
char buf[256];
/* build test image */
for(y=0;y<YSIZE;y++) {
for(x=0;x<XSIZE;x++) {
if (x < XSIZE/2 && y < YSIZE/2) {
if (x < XSIZE/4 && y < YSIZE/4) {
if ((x % 10) <= 6 &&
(y % 10) <= 6)
v = 0xff;
else
v = 0x00;
} else if (x < XSIZE/4) {
if (x & 1)
v = 0xff;
else
v = 0;
} else if (y < XSIZE/4) {
if (y & 1)
v = 0xff;
else
v = 0;
} else {
if (y < YSIZE*3/8) {
if ((y+x) & 1)
v = 0xff;
else
v = 0;
} else {
if (((x+3) % 4) <= 1 &&
((y+3) % 4) <= 1)
v = 0xff;
else
v = 0x00;
}
}
} else if (x < XSIZE/2) {
v = ((x - (XSIZE/2)) * 255) / (XSIZE/2);
} else if (y < XSIZE/2) {
v = ((y - (XSIZE/2)) * 255) / (XSIZE/2);
} else {
v = ((x + y - XSIZE) * 255) / XSIZE;
}
img[(YSIZE - y) * XSIZE + (XSIZE - x)] = v;
}
}
save_pgm("/tmp/in.pgm", img, XSIZE, YSIZE);
for(i=0;i<sizeof(factors)/sizeof(float);i++) {
fact = factors[i];
xsize = (int)(XSIZE * fact);
ysize = (int)((YSIZE - 100) * fact);
s = img_resample_full_init(xsize, ysize, XSIZE, YSIZE, 50 ,50, 0, 0);
printf("Factor=%0.2f\n", fact);
dump_filter(&s->h_filters[0][0]);
component_resample(s, img1, xsize, xsize, ysize,
img + 50 * XSIZE, XSIZE, XSIZE, YSIZE - 100);
img_resample_close(s);
sprintf(buf, "/tmp/out%d.pgm", i);
save_pgm(buf, img1, xsize, ysize);
}
/* mmx test */
#ifdef HAVE_MMX
printf("MMX test\n");
fact = 0.72;
xsize = (int)(XSIZE * fact);
ysize = (int)(YSIZE * fact);
mm_flags = MM_MMX;
s = img_resample_init(xsize, ysize, XSIZE, YSIZE);
component_resample(s, img1, xsize, xsize, ysize,
img, XSIZE, XSIZE, YSIZE);
mm_flags = 0;
s = img_resample_init(xsize, ysize, XSIZE, YSIZE);
component_resample(s, img2, xsize, xsize, ysize,
img, XSIZE, XSIZE, YSIZE);
if (memcmp(img1, img2, xsize * ysize) != 0) {
fprintf(stderr, "mmx error\n");
exit(1);
}
printf("MMX OK\n");
#endif
return 0;
}
#endif
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