typedef struct
{
    uint8_t *buf;
    int nbits;
    uint8_t cur_val;
} MyPutBitContext;

static void init_my_put_bits(MyPutBitContext *pb, uint8_t *buf, size_t buf_len)
{
    pb->buf = buf;
    pb->nbits = 0;
    pb->cur_val = 0;
}

static void my_put_bits(MyPutBitContext *pb, int nbits, int val)
{
    if (nbits == 8) {
        val >>= 2;
        *pb->buf++ = val;
        return;
    }
    if (nbits == 16) {
        *pb->buf++ = val & 0xFF;
        *pb->buf++ = val >> 8;
        return;
    }

    assert(nbits == 10);
    while (nbits) {
        int add_nbits = FFMIN(8 - pb->nbits, nbits);
        pb->cur_val |= (val << pb->nbits);
        pb->nbits += add_nbits;
        nbits -= add_nbits;
        val >>= add_nbits;
        if (pb->nbits == 8) {
            *pb->buf++ = pb->cur_val;
            pb->cur_val = 0;
            pb->nbits = 0;
        }
    }
}