static inline int mpeg1_fast_decode_block_inter(MpegEncContext *s, int16_t *block, int n)
{
    int level, i, j, run;
    RLTable *rl = &ff_rl_mpeg1;
    uint8_t * const scantable = s->intra_scantable.permutated;
    const int qscale          = s->qscale;

    {
        OPEN_READER(re, &s->gb);
        i = -1;
        // special case for first coefficient, no need to add second VLC table
        UPDATE_CACHE(re, &s->gb);
        if (((int32_t)GET_CACHE(re, &s->gb)) < 0) {
            level = (3 * qscale) >> 1;
            level = (level - 1) | 1;
            if (GET_CACHE(re, &s->gb) & 0x40000000)
                level = -level;
            block[0] = level;
            i++;
            SKIP_BITS(re, &s->gb, 2);
            if (((int32_t)GET_CACHE(re, &s->gb)) <= (int32_t)0xBFFFFFFF)
                goto end;
        }

        /* now quantify & encode AC coefficients */
        for (;;) {
            GET_RL_VLC(level, run, re, &s->gb, rl->rl_vlc[0], TEX_VLC_BITS, 2, 0);

            if (level != 0) {
                i += run;
                j = scantable[i];
                level = ((level * 2 + 1) * qscale) >> 1;
                level = (level - 1) | 1;
                level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1);
                SKIP_BITS(re, &s->gb, 1);
            } else {
                /* escape */
                run = SHOW_UBITS(re, &s->gb, 6)+1; LAST_SKIP_BITS(re, &s->gb, 6);
                UPDATE_CACHE(re, &s->gb);
                level = SHOW_SBITS(re, &s->gb, 8); SKIP_BITS(re, &s->gb, 8);
                if (level == -128) {
                    level = SHOW_UBITS(re, &s->gb, 8) - 256; SKIP_BITS(re, &s->gb, 8);
                } else if (level == 0) {
                    level = SHOW_UBITS(re, &s->gb, 8)      ; SKIP_BITS(re, &s->gb, 8);
                }
                i += run;
                j = scantable[i];
                if (level < 0) {
                    level = -level;
                    level = ((level * 2 + 1) * qscale) >> 1;
                    level = (level - 1) | 1;
                    level = -level;
                } else {
                    level = ((level * 2 + 1) * qscale) >> 1;
                    level = (level - 1) | 1;
                }
            }

            block[j] = level;
            if (((int32_t)GET_CACHE(re, &s->gb)) <= (int32_t)0xBFFFFFFF || i >= 64)
                break;
            UPDATE_CACHE(re, &s->gb);
        }
end:
        LAST_SKIP_BITS(re, &s->gb, 2);
        CLOSE_READER(re, &s->gb);
    }
    s->block_last_index[n] = i;
    return 0;
}