Hello I bought lightning digital AV adapter to mirror video in TV but when I call some one FaceTime the audio doesn't work in TV only picture you can see

Hello abnaji1984,

It sounds like you are able to see the video from your phone on your TV but cannot hear the audio from the phone on your TV. This is expected behaviour, and in the article that you used it shows that the iPod Touch only support video mirroring with the lightning AV adapter:

iOS: About Apple Digital AV Adapters

Thank you for using Apple Support Communities.

All the best,

Sterling

But but poster said he has a " I bought lightning digital AV adapter ".