Is there a way to cast from my phone to a first gen chromecast without using mobile data? I thought I could do this by downloading films to my phone and then stream to cc, but it seems to throttle my tethering data.

So I’m not sure if I’m understanding the way this works: I thought it would just cast from phone to tv - but it’s using huge chunks of data for small films and my plan is limited.

Any advice on this or better ways to do this?