static inline int64_t bs_get_v(const uint8_t **bs)
{
    int64_t v = 0;
    int br = 0;
    int c;

    do {
        c = **bs; (*bs)++;
        v <<= 7;
        v |= c & 0x7F;
        br++;
        if (br > 10)
            return -1;
    } while (c & 0x80);

    return v - br;
}