int av_image_alloc(uint8_t *pointers[4], int linesizes[4],
                   int w, int h, enum PixelFormat pix_fmt, int align)
{
    int i, ret;
    uint8_t *buf;

    if ((ret = av_image_check_size(w, h, 0, NULL)) < 0)
        return ret;
    if ((ret = av_image_fill_linesizes(linesizes, pix_fmt, align>7 ? FFALIGN(w, 8) : w)) < 0)
        return ret;

    for (i = 0; i < 4; i++)
        linesizes[i] = FFALIGN(linesizes[i], align);

    if ((ret = av_image_fill_pointers(pointers, pix_fmt, h, NULL, linesizes)) < 0)
        return ret;
    buf = av_malloc(ret + align);
    if (!buf)
        return AVERROR(ENOMEM);
    if ((ret = av_image_fill_pointers(pointers, pix_fmt, h, buf, linesizes)) < 0) {
        av_free(buf);
        return ret;
    }
    if (av_pix_fmt_descriptors[pix_fmt].flags & PIX_FMT_PAL ||
        av_pix_fmt_descriptors[pix_fmt].flags & PIX_FMT_PSEUDOPAL)
        ff_set_systematic_pal2((uint32_t*)pointers[1], pix_fmt);

    return ret;
}