imgconvert.c

ffmpeg的完整源代码和作者自己写的文档。不但有在Linux的工程哦

    for(;height > 0; height--) {
        for(w = width;w > 0; w--) {
            int tmp=0;
            for(i=0; i<8; i++){
                tmp += src[0] + src[1] + src[2] + src[3] + src[4] + src[5] + src[6] + src[7];
                src += src_wrap;
            }
            *(dst++) = (tmp + 32)>>6;
            src += 8 - 8*src_wrap;
        }
        src += 8*src_wrap - 8*width;
        dst += dst_wrap - width;
    }
}

static void grow21_line(uint8_t *dst, const uint8_t *src,
                        int width)
{
    int w;
    const uint8_t *s1;
    uint8_t *d;

    s1 = src;
    d = dst;
    for(w = width;w >= 4; w-=4) {
        d[1] = d[0] = s1[0];
        d[3] = d[2] = s1[1];
        s1 += 2;
        d += 4;
    }
    for(;w >= 2; w -= 2) {
        d[1] = d[0] = s1[0];
        s1 ++;
        d += 2;
    }
    /* only needed if width is not a multiple of two */
    /* XXX: veryfy that */
    if (w) {
        d[0] = s1[0];
    }
}

static void grow41_line(uint8_t *dst, const uint8_t *src,
                        int width)
{
    int w, v;
    const uint8_t *s1;
    uint8_t *d;

    s1 = src;
    d = dst;
    for(w = width;w >= 4; w-=4) {
        v = s1[0];
        d[0] = v;
        d[1] = v;
        d[2] = v;
        d[3] = v;
        s1 ++;
        d += 4;
    }
}

/* 1x1 -> 2x1 */
static void grow21(uint8_t *dst, int dst_wrap,
                   const uint8_t *src, int src_wrap,
                   int width, int height)
{
    for(;height > 0; height--) {
        grow21_line(dst, src, width);
        src += src_wrap;
        dst += dst_wrap;
    }
}

/* 1x1 -> 1x2 */
static void grow12(uint8_t *dst, int dst_wrap,
                   const uint8_t *src, int src_wrap,
                   int width, int height)
{
    for(;height > 0; height-=2) {
        memcpy(dst, src, width);
        dst += dst_wrap;
        memcpy(dst, src, width);
        dst += dst_wrap;
        src += src_wrap;
    }
}

/* 1x1 -> 2x2 */
static void grow22(uint8_t *dst, int dst_wrap,
                   const uint8_t *src, int src_wrap,
                   int width, int height)
{
    for(;height > 0; height--) {
        grow21_line(dst, src, width);
        if (height%2)
            src += src_wrap;
        dst += dst_wrap;
    }
}

/* 1x1 -> 4x1 */
static void grow41(uint8_t *dst, int dst_wrap,
                   const uint8_t *src, int src_wrap,
                   int width, int height)
{
    for(;height > 0; height--) {
        grow41_line(dst, src, width);
        src += src_wrap;
        dst += dst_wrap;
    }
}

/* 1x1 -> 4x4 */
static void grow44(uint8_t *dst, int dst_wrap,
                   const uint8_t *src, int src_wrap,
                   int width, int height)
{
    for(;height > 0; height--) {
        grow41_line(dst, src, width);
        if ((height & 3) == 1)
            src += src_wrap;
        dst += dst_wrap;
    }
}

/* 1x2 -> 2x1 */
static void conv411(uint8_t *dst, int dst_wrap,
                    const uint8_t *src, int src_wrap,
                    int width, int height)
{
    int w, c;
    const uint8_t *s1, *s2;
    uint8_t *d;

    width>>=1;

    for(;height > 0; height--) {
        s1 = src;
        s2 = src + src_wrap;
        d = dst;
        for(w = width;w > 0; w--) {
            c = (s1[0] + s2[0]) >> 1;
            d[0] = c;
            d[1] = c;
            s1++;
            s2++;
            d += 2;
        }
        src += src_wrap * 2;
        dst += dst_wrap;
    }
}

/* XXX: add jpeg quantize code */

#define TRANSP_INDEX (6*6*6)

/* this is maybe slow, but allows for extensions */
static inline unsigned char gif_clut_index(uint8_t r, uint8_t g, uint8_t b)
{
    return ((((r)/47)%6)*6*6+(((g)/47)%6)*6+(((b)/47)%6));
}

static void build_rgb_palette(uint8_t *palette, int has_alpha)
{
    uint32_t *pal;
    static const uint8_t pal_value[6] = { 0x00, 0x33, 0x66, 0x99, 0xcc, 0xff };
    int i, r, g, b;

    pal = (uint32_t *)palette;
    i = 0;
    for(r = 0; r < 6; r++) {
        for(g = 0; g < 6; g++) {
            for(b = 0; b < 6; b++) {
                pal[i++] = (0xff << 24) | (pal_value[r] << 16) |
                    (pal_value[g] << 8) | pal_value[b];
            }
        }
    }
    if (has_alpha)
        pal[i++] = 0;
    while (i < 256)
        pal[i++] = 0xff000000;
}

/* copy bit n to bits 0 ... n - 1 */
static inline unsigned int bitcopy_n(unsigned int a, int n)
{
    int mask;
    mask = (1 << n) - 1;
    return (a & (0xff & ~mask)) | ((-((a >> n) & 1)) & mask);
}

/* rgb555 handling */

#define RGB_NAME rgb555

#define RGB_IN(r, g, b, s)\
{\
    unsigned int v = ((const uint16_t *)(s))[0];\
    r = bitcopy_n(v >> (10 - 3), 3);\
    g = bitcopy_n(v >> (5 - 3), 3);\
    b = bitcopy_n(v << 3, 3);\
}


#define RGB_OUT(d, r, g, b)\
{\
    ((uint16_t *)(d))[0] = ((r >> 3) << 10) | ((g >> 3) << 5) | (b >> 3);\
}

#define BPP 2

#include "imgconvert_template.h"

/* rgb565 handling */

#define RGB_NAME rgb565

#define RGB_IN(r, g, b, s)\
{\
    unsigned int v = ((const uint16_t *)(s))[0];\
    r = bitcopy_n(v >> (11 - 3), 3);\
    g = bitcopy_n(v >> (5 - 2), 2);\
    b = bitcopy_n(v << 3, 3);\
}

#define RGB_OUT(d, r, g, b)\
{\
    ((uint16_t *)(d))[0] = ((r >> 3) << 11) | ((g >> 2) << 5) | (b >> 3);\
}

#define BPP 2

#include "imgconvert_template.h"

/* bgr24 handling */

#define RGB_NAME bgr24

#define RGB_IN(r, g, b, s)\
{\
    b = (s)[0];\
    g = (s)[1];\
    r = (s)[2];\
}

#define RGB_OUT(d, r, g, b)\
{\
    (d)[0] = b;\
    (d)[1] = g;\
    (d)[2] = r;\
}

#define BPP 3

#include "imgconvert_template.h"

#undef RGB_IN
#undef RGB_OUT
#undef BPP

/* rgb24 handling */

#define RGB_NAME rgb24
#define FMT_RGB24

#define RGB_IN(r, g, b, s)\
{\
    r = (s)[0];\
    g = (s)[1];\
    b = (s)[2];\
}

#define RGB_OUT(d, r, g, b)\
{\
    (d)[0] = r;\
    (d)[1] = g;\
    (d)[2] = b;\
}

#define BPP 3

#include "imgconvert_template.h"

/* rgb32 handling */

#define RGB_NAME rgb32
#define FMT_RGB32

#define RGB_IN(r, g, b, s)\
{\
    unsigned int v = ((const uint32_t *)(s))[0];\
    r = (v >> 16) & 0xff;\
    g = (v >> 8) & 0xff;\
    b = v & 0xff;\
}

#define RGBA_IN(r, g, b, a, s)\
{\
    unsigned int v = ((const uint32_t *)(s))[0];\
    a = (v >> 24) & 0xff;\
    r = (v >> 16) & 0xff;\
    g = (v >> 8) & 0xff;\
    b = v & 0xff;\
}

#define RGBA_OUT(d, r, g, b, a)\
{\
    ((uint32_t *)(d))[0] = (a << 24) | (r << 16) | (g << 8) | b;\
}

#define BPP 4

#include "imgconvert_template.h"

static void mono_to_gray(AVPicture *dst, const AVPicture *src,
                         int width, int height, int xor_mask)
{
    const unsigned char *p;
    unsigned char *q;
    int v, dst_wrap, src_wrap;
    int y, w;

    p = src->data[0];
    src_wrap = src->linesize[0] - ((width + 7) >> 3);

    q = dst->data[0];
    dst_wrap = dst->linesize[0] - width;
    for(y=0;y<height;y++) {
        w = width;
        while (w >= 8) {
            v = *p++ ^ xor_mask;
            q[0] = -(v >> 7);
            q[1] = -((v >> 6) & 1);
            q[2] = -((v >> 5) & 1);
            q[3] = -((v >> 4) & 1);
            q[4] = -((v >> 3) & 1);
            q[5] = -((v >> 2) & 1);
            q[6] = -((v >> 1) & 1);
            q[7] = -((v >> 0) & 1);
            w -= 8;
            q += 8;
        }
        if (w > 0) {
            v = *p++ ^ xor_mask;
            do {
                q[0] = -((v >> 7) & 1);
                q++;
                v <<= 1;
            } while (--w);
        }
        p += src_wrap;
        q += dst_wrap;
    }
}

static void monowhite_to_gray(AVPicture *dst, const AVPicture *src,
                               int width, int height)
{
    mono_to_gray(dst, src, width, height, 0xff);
}

static void monoblack_to_gray(AVPicture *dst, const AVPicture *src,
                               int width, int height)
{
    mono_to_gray(dst, src, width, height, 0x00);
}

static void gray_to_mono(AVPicture *dst, const AVPicture *src,
                         int width, int height, int xor_mask)
{
    int n;
    const uint8_t *s;
    uint8_t *d;
    int j, b, v, n1, src_wrap, dst_wrap, y;

    s = src->data[0];
    src_wrap = src->linesize[0] - width;

    d = dst->data[0];
    dst_wrap = dst->linesize[0] - ((width + 7) >> 3);

    for(y=0;y<height;y++) {
        n = width;
        while (n >= 8) {
            v = 0;
            for(j=0;j<8;j++) {
                b = s[0];
                s++;
                v = (v << 1) | (b >> 7);
            }
            d[0] = v ^ xor_mask;
            d++;
            n -= 8;
        }
        if (n > 0) {
            n1 = n;
            v = 0;
            while (n > 0) {
                b = s[0];
                s++;
                v = (v << 1) | (b >> 7);
                n--;
            }
            d[0] = (v << (8 - (n1 & 7))) ^ xor_mask;
            d++;
        }
        s += src_wrap;
        d += dst_wrap;
    }
}

static void gray_to_monowhite(AVPicture *dst, const AVPicture *src,
                              int width, int height)
{
    gray_to_mono(dst, src, width, height, 0xff);
}

static void gray_to_monoblack(AVPicture *dst, const AVPicture *src,
                              int width, int height)
{
    gray_to_mono(dst, src, width, height, 0x00);
}

static void gray_to_gray16(AVPicture *dst, const AVPicture *src,
                              int width, int height)
{
    int x, y, src_wrap, dst_wrap;
    uint8_t *s, *d;
    s = src->data[0];
    src_wrap = src->linesize[0] - width;
    d = dst->data[0];
    dst_wrap = dst->linesize[0] - width * 2;
    for(y=0; y<height; y++){
        for(x=0; x<width; x++){
            *d++ = *s;
            *d++ = *s++;
        }
        s += src_wrap;
        d += dst_wrap;
    }
}

static void gray16_to_gray(AVPicture *dst, const AVPicture *src,
                              int width, int height)
{
    int x, y, src_wrap, dst_wrap;
    uint8_t *s, *d;
    s = src->data[0];
    src_wrap = src->linesize[0] - width * 2;
    d = dst->data[0];
    dst_wrap = dst->linesize[0] - width;
    for(y=0; y<height; y++){
        for(x=0; x<width; x++){
            *d++ = *s;
            s += 2;
        }
        s += src_wrap;
        d += dst_wrap;
    }
}

static void gray16be_to_gray(AVPicture *dst, const AVPicture *src,
                              int width, int height)
{
    gray16_to_gray(dst, src, width, height);
}

static void gray16le_to_gray(AVPicture *dst, const AVPicture *src,
                              int width, int height)