imgresample.c

F:图像处理资料264264书籍ffmpeg-0.4.9-pre1VideoStream.rar 一个视频解压缩源代码

/*
 * 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;
    int topBand, bottomBand, leftBand, rightBand;
    int padtop, padbottom, padleft, padright;
    int pad_owidth, pad_oheight;
    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;
};

void av_build_filter(int16_t *filter, double factor, int tap_count, int phase_count, int scale, int type);

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, const uint8_t *src,
			    int src_width, int src_start, int src_incr,
			    int16_t *filters)
{
    int src_pos, phase, sum, i;
    const 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, const uint8_t *src,
		       int wrap, int16_t *filter)
{
    int sum, i;
    const 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,
				 const uint8_t *src, int src_width,
                                 int src_start, int src_incr, int16_t *filters)
{
    int src_pos, phase;
    const 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, const uint8_t *src,
			    int wrap, int16_t *filter)
{
    int sum, i, v;
    const 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, const uint8_t *src,
			  int wrap, int16_t *filter)
{
    int sum, i;
    const 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;
    }

    /*