Can I splice hdmi to lightning iPhone cable? I do a lot of things like this with other wires. But some require a converter/brain if you will?

Couldn't find anything online so itnleads me to believe that the two signals are not the same, or compatible? I was going to order the cable off eBay but why if I have several hdmi cords and iPhone chargers?

The goal is to mirror my iPhone on to my tv by the way

I wouldn't HDMI cables are expensive.

No, but you can buy a Lightning to HDMI adapter. The Lightning connector has 8 pins, the HDMI connector 19 pins.

No.

Lightning is a bus interface system, like USB or PCIe. It needs active electronics that the phone/tablet recognises as a valid device to actually do anything.

You can get a genuine Apple HDMI-out converter, as another answer says - and any other types of interface connections,

Note that some places on ebay sell cables with totally incompatible connectors and no electronics. They do nothing useful and may cause damage.