static Stream decode(Stream src, int startbit, int bits)
{
    MemoryStream res = new MemoryStream(bits / 8);
    int srcbit = startbit;
    int resbit = 0;
    byte a = srcbit == 0 ? (byte)0 : (byte)(src.ReadByte() >> srcbit);
    byte b = 0;
    while (bits-- > 0) {
        b >>= 1;
        if ((a & 1) != 0) b |= 0x80;
        a >>= 1;

        if (++srcbit == 8) {
            a = (byte)src.ReadByte();
            srcbit = 0;
        }
        if (++resbit == 8) {
            resbit = 0;
            res.WriteByte(b);
        }
    }
    return res;
}