Yes, convert the video with a free program like
Handbrake to a file format ideal of AppleTV like H.265.
Or edit it first in FCPX or iMovie and you can then render an ideal file for AppleTV from either of those.
This will flip your links in the (apparent) chain:
- from TV to AppleTV to HPs
- to AppleTV to both TV and HPs
In other words, AppleTV will be your source instead of working through the TV.
If that's already how you have it, AppleTV sharing with HPs shouldn't care what TV you have. In other words, it shouldn't be sending audio over to TV, back again and then to HPs. It should be going direct to HPs... unless perhaps you are using a different source for the video, like a stick or blu ray player or cable/satt box plugged into the TV. If:
- USB stick, see those first recommendations above about converting video from the stick source into an AppleTV file to then toss video to TV and audio to HPs FROM AppleTV.
- Blu Ray, learn to rip those into a format for direct playback on AppleTV.
- cable/satt/other streaming box, you don't have any great option if you can't tweak the audio delay settings in that TV.
Another test would be to run the same video file on a computer and see if it is also out of sync without involving AppleTV, HPs or that Sony. If it's also out of sync on the computer, the file itself needs work to get audio and video aligned. You can do this in FCPX quite easily. I don't know about iMovie.
If the file is fine (audio syncs with video) on another device, go into the menus of the TV and look for any audio delay settings. I entered "Sony A95K audio delay" in a search field and found many matches with apparently step-by-step instructions on how to adjust audio delay.
If you are trying to make sources OTHER than AppleTV work well, you might want to change your approach. Consider going the classic Receiver + "dumb" speakers route for audio and then wire in the variety of sources (including AppleTV) into Receiver, basically dumping trying to make the wireless link to HPs for sources other than AppleTV. Then perhaps repurpose the HPs for other rooms.