swscale_altivec_template.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

        vector unsigned char src_v0 = vec_ld(srcPos, src);
        vector unsigned char src_v1, src_vF;
        vector signed short src_v, filter_v;
        vector signed int val_v, val_s;
        if ((((int)src + srcPos)% 16) > 8) {
            src_v1 = vec_ld(srcPos + 16, src);
        }
        src_vF = vec_perm(src_v0, src_v1, vec_lvsl(srcPos, src));

        src_v = // vec_unpackh sign-extends...
            (vector signed short)(vec_mergeh((vector unsigned char)vzero, src_vF));
        filter_v = vec_ld(i << 4, filter);
        // the 4 above is 3 (filterSize == 8) + 1 (sizeof(short) == 2)

        val_v = vec_msums(src_v, filter_v, (vector signed int)vzero);
        val_s = vec_sums(val_v, vzero);
        vec_st(val_s, 0, tempo);
        dst[i] = av_clip(tempo[3]>>7, 0, (1<<15)-1);
    }
    }
    break;

    case 16:
    {
        for (i=0; i<dstW; i++) {
            register int srcPos = filterPos[i];

            vector unsigned char src_v0 = vec_ld(srcPos, src);
            vector unsigned char src_v1 = vec_ld(srcPos + 16, src);
            vector unsigned char src_vF = vec_perm(src_v0, src_v1, vec_lvsl(srcPos, src));

            vector signed short src_vA = // vec_unpackh sign-extends...
                (vector signed short)(vec_mergeh((vector unsigned char)vzero, src_vF));
            vector signed short src_vB = // vec_unpackh sign-extends...
                (vector signed short)(vec_mergel((vector unsigned char)vzero, src_vF));

            vector signed short filter_v0 = vec_ld(i << 5, filter);
            vector signed short filter_v1 = vec_ld((i << 5) + 16, filter);
            // the 5 above are 4 (filterSize == 16) + 1 (sizeof(short) == 2)

            vector signed int val_acc = vec_msums(src_vA, filter_v0, (vector signed int)vzero);
            vector signed int val_v = vec_msums(src_vB, filter_v1, val_acc);

            vector signed int val_s = vec_sums(val_v, vzero);

            vec_st(val_s, 0, tempo);
            dst[i] = av_clip(tempo[3]>>7, 0, (1<<15)-1);
        }
    }
    break;

    default:
    {
    for (i=0; i<dstW; i++) {
        register int j;
        register int srcPos = filterPos[i];

        vector signed int val_s, val_v = (vector signed int)vzero;
        vector signed short filter_v0R = vec_ld(i * 2 * filterSize, filter);
        vector unsigned char permF = vec_lvsl((i * 2 * filterSize), filter);

        vector unsigned char src_v0 = vec_ld(srcPos, src);
        vector unsigned char permS = vec_lvsl(srcPos, src);

        for (j = 0 ; j < filterSize - 15; j += 16) {
            vector unsigned char src_v1 = vec_ld(srcPos + j + 16, src);
            vector unsigned char src_vF = vec_perm(src_v0, src_v1, permS);

            vector signed short src_vA = // vec_unpackh sign-extends...
                (vector signed short)(vec_mergeh((vector unsigned char)vzero, src_vF));
            vector signed short src_vB = // vec_unpackh sign-extends...
                (vector signed short)(vec_mergel((vector unsigned char)vzero, src_vF));

            vector signed short filter_v1R = vec_ld((i * 2 * filterSize) + (j * 2) + 16, filter);
            vector signed short filter_v2R = vec_ld((i * 2 * filterSize) + (j * 2) + 32, filter);
            vector signed short filter_v0  = vec_perm(filter_v0R, filter_v1R, permF);
            vector signed short filter_v1  = vec_perm(filter_v1R, filter_v2R, permF);

            vector signed int val_acc = vec_msums(src_vA, filter_v0, val_v);
            val_v = vec_msums(src_vB, filter_v1, val_acc);

            filter_v0R = filter_v2R;
            src_v0 = src_v1;
        }

        if (j < (filterSize-7)) {
            // loading src_v0 is useless, it's already done above
            //vector unsigned char src_v0 = vec_ld(srcPos + j, src);
            vector unsigned char src_v1, src_vF;
            vector signed short src_v, filter_v1R, filter_v;
            if ((((int)src + srcPos)% 16) > 8) {
                src_v1 = vec_ld(srcPos + j + 16, src);
            }
            src_vF = vec_perm(src_v0, src_v1, permS);

            src_v = // vec_unpackh sign-extends...
                (vector signed short)(vec_mergeh((vector unsigned char)vzero, src_vF));
            // loading filter_v0R is useless, it's already done above
            //vector signed short filter_v0R = vec_ld((i * 2 * filterSize) + j, filter);
            filter_v1R = vec_ld((i * 2 * filterSize) + (j * 2) + 16, filter);
            filter_v = vec_perm(filter_v0R, filter_v1R, permF);

            val_v = vec_msums(src_v, filter_v, val_v);
        }

        val_s = vec_sums(val_v, vzero);

        vec_st(val_s, 0, tempo);
        dst[i] = av_clip(tempo[3]>>7, 0, (1<<15)-1);
    }

    }
    }
}

static inline int yv12toyuy2_unscaled_altivec(SwsContext *c, uint8_t* src[], int srcStride[], int srcSliceY,
                                              int srcSliceH, uint8_t* dstParam[], int dstStride_a[]) {
    uint8_t *dst=dstParam[0] + dstStride_a[0]*srcSliceY;
    // yv12toyuy2( src[0],src[1],src[2],dst,c->srcW,srcSliceH,srcStride[0],srcStride[1],dstStride[0] );
    uint8_t *ysrc = src[0];
    uint8_t *usrc = src[1];
    uint8_t *vsrc = src[2];
    const int width = c->srcW;
    const int height = srcSliceH;
    const int lumStride = srcStride[0];
    const int chromStride = srcStride[1];
    const int dstStride = dstStride_a[0];
    const vector unsigned char yperm = vec_lvsl(0, ysrc);
    const int vertLumPerChroma = 2;
    register unsigned int y;

    if (width&15) {
        yv12toyuy2( ysrc, usrc, vsrc, dst,c->srcW,srcSliceH, lumStride, chromStride, dstStride);
        return srcSliceH;
    }

    /* this code assume:

    1) dst is 16 bytes-aligned
    2) dstStride is a multiple of 16
    3) width is a multiple of 16
    4) lum&chrom stride are multiple of 8
    */

    for (y=0; y<height; y++) {
        int i;
        for (i = 0; i < width - 31; i+= 32) {
            const unsigned int j = i >> 1;
            vector unsigned char v_yA = vec_ld(i, ysrc);
            vector unsigned char v_yB = vec_ld(i + 16, ysrc);
            vector unsigned char v_yC = vec_ld(i + 32, ysrc);
            vector unsigned char v_y1 = vec_perm(v_yA, v_yB, yperm);
            vector unsigned char v_y2 = vec_perm(v_yB, v_yC, yperm);
            vector unsigned char v_uA = vec_ld(j, usrc);
            vector unsigned char v_uB = vec_ld(j + 16, usrc);
            vector unsigned char v_u = vec_perm(v_uA, v_uB, vec_lvsl(j, usrc));
            vector unsigned char v_vA = vec_ld(j, vsrc);
            vector unsigned char v_vB = vec_ld(j + 16, vsrc);
            vector unsigned char v_v = vec_perm(v_vA, v_vB, vec_lvsl(j, vsrc));
            vector unsigned char v_uv_a = vec_mergeh(v_u, v_v);
            vector unsigned char v_uv_b = vec_mergel(v_u, v_v);
            vector unsigned char v_yuy2_0 = vec_mergeh(v_y1, v_uv_a);
            vector unsigned char v_yuy2_1 = vec_mergel(v_y1, v_uv_a);
            vector unsigned char v_yuy2_2 = vec_mergeh(v_y2, v_uv_b);
            vector unsigned char v_yuy2_3 = vec_mergel(v_y2, v_uv_b);
            vec_st(v_yuy2_0, (i << 1), dst);
            vec_st(v_yuy2_1, (i << 1) + 16, dst);
            vec_st(v_yuy2_2, (i << 1) + 32, dst);
            vec_st(v_yuy2_3, (i << 1) + 48, dst);
        }
        if (i < width) {
            const unsigned int j = i >> 1;
            vector unsigned char v_y1 = vec_ld(i, ysrc);
            vector unsigned char v_u = vec_ld(j, usrc);
            vector unsigned char v_v = vec_ld(j, vsrc);
            vector unsigned char v_uv_a = vec_mergeh(v_u, v_v);
            vector unsigned char v_yuy2_0 = vec_mergeh(v_y1, v_uv_a);
            vector unsigned char v_yuy2_1 = vec_mergel(v_y1, v_uv_a);
            vec_st(v_yuy2_0, (i << 1), dst);
            vec_st(v_yuy2_1, (i << 1) + 16, dst);
        }
        if ( (y&(vertLumPerChroma-1))==(vertLumPerChroma-1) ) {
            usrc += chromStride;
            vsrc += chromStride;
        }
        ysrc += lumStride;
        dst += dstStride;
    }

    return srcSliceH;
}

static inline int yv12touyvy_unscaled_altivec(SwsContext *c, uint8_t* src[], int srcStride[], int srcSliceY,
                                              int srcSliceH, uint8_t* dstParam[], int dstStride_a[]) {
    uint8_t *dst=dstParam[0] + dstStride_a[0]*srcSliceY;
    // yv12toyuy2( src[0],src[1],src[2],dst,c->srcW,srcSliceH,srcStride[0],srcStride[1],dstStride[0] );
    uint8_t *ysrc = src[0];
    uint8_t *usrc = src[1];
    uint8_t *vsrc = src[2];
    const int width = c->srcW;
    const int height = srcSliceH;
    const int lumStride = srcStride[0];
    const int chromStride = srcStride[1];
    const int dstStride = dstStride_a[0];
    const int vertLumPerChroma = 2;
    const vector unsigned char yperm = vec_lvsl(0, ysrc);
    register unsigned int y;

    if (width&15) {
        yv12touyvy( ysrc, usrc, vsrc, dst,c->srcW,srcSliceH, lumStride, chromStride, dstStride);
        return srcSliceH;
    }

    /* this code assume:

    1) dst is 16 bytes-aligned
    2) dstStride is a multiple of 16
    3) width is a multiple of 16
    4) lum&chrom stride are multiple of 8
    */

    for (y=0; y<height; y++) {
        int i;
        for (i = 0; i < width - 31; i+= 32) {
            const unsigned int j = i >> 1;
            vector unsigned char v_yA = vec_ld(i, ysrc);
            vector unsigned char v_yB = vec_ld(i + 16, ysrc);
            vector unsigned char v_yC = vec_ld(i + 32, ysrc);
            vector unsigned char v_y1 = vec_perm(v_yA, v_yB, yperm);
            vector unsigned char v_y2 = vec_perm(v_yB, v_yC, yperm);
            vector unsigned char v_uA = vec_ld(j, usrc);
            vector unsigned char v_uB = vec_ld(j + 16, usrc);
            vector unsigned char v_u = vec_perm(v_uA, v_uB, vec_lvsl(j, usrc));
            vector unsigned char v_vA = vec_ld(j, vsrc);
            vector unsigned char v_vB = vec_ld(j + 16, vsrc);
            vector unsigned char v_v = vec_perm(v_vA, v_vB, vec_lvsl(j, vsrc));
            vector unsigned char v_uv_a = vec_mergeh(v_u, v_v);
            vector unsigned char v_uv_b = vec_mergel(v_u, v_v);
            vector unsigned char v_uyvy_0 = vec_mergeh(v_uv_a, v_y1);
            vector unsigned char v_uyvy_1 = vec_mergel(v_uv_a, v_y1);
            vector unsigned char v_uyvy_2 = vec_mergeh(v_uv_b, v_y2);
            vector unsigned char v_uyvy_3 = vec_mergel(v_uv_b, v_y2);
            vec_st(v_uyvy_0, (i << 1), dst);
            vec_st(v_uyvy_1, (i << 1) + 16, dst);
            vec_st(v_uyvy_2, (i << 1) + 32, dst);
            vec_st(v_uyvy_3, (i << 1) + 48, dst);
        }
        if (i < width) {
            const unsigned int j = i >> 1;
            vector unsigned char v_y1 = vec_ld(i, ysrc);
            vector unsigned char v_u = vec_ld(j, usrc);
            vector unsigned char v_v = vec_ld(j, vsrc);
            vector unsigned char v_uv_a = vec_mergeh(v_u, v_v);
            vector unsigned char v_uyvy_0 = vec_mergeh(v_uv_a, v_y1);
            vector unsigned char v_uyvy_1 = vec_mergel(v_uv_a, v_y1);
            vec_st(v_uyvy_0, (i << 1), dst);
            vec_st(v_uyvy_1, (i << 1) + 16, dst);
        }
        if ( (y&(vertLumPerChroma-1))==(vertLumPerChroma-1) ) {
            usrc += chromStride;
            vsrc += chromStride;
        }
        ysrc += lumStride;
        dst += dstStride;
    }
    return srcSliceH;
}