JD94:
You're awesome..!!
I was getting so very annoyed at my 2013 Apple TV (rev A) momentarily freezing the video that was being mirrored from my 2012 MacBook Air.
I was convinced that there was a glitch with my ATV. I also wondered if maybe there was a Wi-Fi issue with my home network, where maybe the ATV was sitting in a dead-zone. I moved the ATV around on my TV stand, but the freezing video continued.
The video would continue to play on my MB Air, but the mirrored video would temporarily freeze on my TV for about 3-5 seconds, then it would catch up and play normal. Unlike some others, there didn't seem to be any predictable time increments of when this would happen, although I have noticed that the freezing issue was more prevalent when there seems to be a lot of fast moving action in the video (like Captain America fighting the bad guys, with lots of explosions happening in the background, and helicopters flying around and stuff, but less noticeable during the quiet, dull, slow-moving scenes).
I normally convert my .avi/.mkv movies to .mp4 using Wondershare Video Converter Ultimate, and mirror the movies from my MB Air to the ATV via QuickTime (currently using v10.3).
I tried JD94's suggestion of using VLC instead of QuickTime, and was pleasantly surprised that I haven't yet observed any freezing video issues yet (although I haven't watched an entire movie yet with VLC, only the parts that were terrible with QT).
I've changed my default setting to now use VLC with all .mp4 files. Hopefully this fixes my issue.
Thank you, JD94. You may have saved my sanity. 😀