s->bit_buf |= ~1U >> s->bit_cnt;
void jflush_put_bits(PutBitContext *s){    unsigned int b;    while (s->bit_cnt > 0) {        b = s->bit_buf >> 24;        *s->buf_ptr++ = b;        if (b == 0xff)            *s->buf_ptr++ = 0;        s->bit_buf<<=8;        s->bit_cnt-=8;    }    flush_buffer(s);    s->bit_cnt=0;    s->bit_buf=0;}