static av_always_inline void xchg_mb_border(H264Context *h, uint8_t *src_y,
                                            uint8_t *src_cb, uint8_t *src_cr,
                                            int linesize, int uvlinesize,
                                            int xchg, int chroma444,
                                            int simple, int pixel_shift)
{
    int deblock_topleft;
    int deblock_top;
    int top_idx = 1;
    uint8_t *top_border_m1;
    uint8_t *top_border;

    if (!simple && FRAME_MBAFF(h)) {
        if (h->mb_y & 1) {
            if (!MB_MBAFF(h))
                return;
        } else {
            top_idx = MB_MBAFF(h) ? 0 : 1;
        }
    }

    if (h->deblocking_filter == 2) {
        deblock_topleft = h->slice_table[h->mb_xy - 1 - h->mb_stride] == h->slice_num;
        deblock_top     = h->top_type;
    } else {
        deblock_topleft = (h->mb_x > 0);
        deblock_top     = (h->mb_y > !!MB_FIELD(h));
    }

    src_y  -= linesize   + 1 + pixel_shift;
    src_cb -= uvlinesize + 1 + pixel_shift;
    src_cr -= uvlinesize + 1 + pixel_shift;

    top_border_m1 = h->top_borders[top_idx][h->mb_x - 1];
    top_border    = h->top_borders[top_idx][h->mb_x];

#define XCHG(a, b, xchg)                        \
    if (pixel_shift) {                          \
        if (xchg) {                             \
            AV_SWAP64(b + 0, a + 0);            \
            AV_SWAP64(b + 8, a + 8);            \
        } else {                                \
            AV_COPY128(b, a);                   \
        }                                       \
    } else if (xchg)                            \
        AV_SWAP64(b, a);                        \
    else                                        \
        AV_COPY64(b, a);

    if (deblock_top) {
        if (deblock_topleft) {
            XCHG(top_border_m1 + (8 << pixel_shift),
                 src_y - (7 << pixel_shift), 1);
        }
        XCHG(top_border + (0 << pixel_shift), src_y + (1 << pixel_shift), xchg);
        XCHG(top_border + (8 << pixel_shift), src_y + (9 << pixel_shift), 1);
        if (h->mb_x + 1 < h->mb_width) {
            XCHG(h->top_borders[top_idx][h->mb_x + 1],
                 src_y + (17 << pixel_shift), 1);
        }
        if (simple || !CONFIG_GRAY || !(h->flags & CODEC_FLAG_GRAY)) {
            if (chroma444) {
                if (deblock_topleft) {
                    XCHG(top_border_m1 + (24 << pixel_shift), src_cb - (7 << pixel_shift), 1);
                    XCHG(top_border_m1 + (40 << pixel_shift), src_cr - (7 << pixel_shift), 1);
                }
                XCHG(top_border + (16 << pixel_shift), src_cb + (1 << pixel_shift), xchg);
                XCHG(top_border + (24 << pixel_shift), src_cb + (9 << pixel_shift), 1);
                XCHG(top_border + (32 << pixel_shift), src_cr + (1 << pixel_shift), xchg);
                XCHG(top_border + (40 << pixel_shift), src_cr + (9 << pixel_shift), 1);
                if (h->mb_x + 1 < h->mb_width) {
                    XCHG(h->top_borders[top_idx][h->mb_x + 1] + (16 << pixel_shift), src_cb + (17 << pixel_shift), 1);
                    XCHG(h->top_borders[top_idx][h->mb_x + 1] + (32 << pixel_shift), src_cr + (17 << pixel_shift), 1);
                }
            } else {
                if (deblock_topleft) {
                    XCHG(top_border_m1 + (16 << pixel_shift), src_cb - (7 << pixel_shift), 1);
                    XCHG(top_border_m1 + (24 << pixel_shift), src_cr - (7 << pixel_shift), 1);
                }
                XCHG(top_border + (16 << pixel_shift), src_cb + 1 + pixel_shift, 1);
                XCHG(top_border + (24 << pixel_shift), src_cr + 1 + pixel_shift, 1);
            }
        }
    }
}

Unknown