Can I airplay m3u8 video file to AppleTV?

Below are the formats accepted for the 4th gen

• HEVC SDR up to 1080p, 30 fps, Main/Main 10 profile
• H.264 video up to 1080p, 60 fps, High or Main Profile level 4.2 or lower
• H.264 Baseline Profile level 3.0 or lower with AAC-LC audio up to 160 Kbps per channel, 48kHz, stereo audio in .m4v, .mp4 and .mov file formats
• MPEG-4 video up to 2.5 Mbps, 640 by 480 pixels, 30 fps, Simple Profile with AAC-LC audio up to 160 Kbps, 48kHz, stereo audio in .m4v, .mp4 and .mov file formats

M3U8 is not a file format per se, more like a playlist (often of video segments), meaning that it can use almost any video format, some of which may be compatible with AirPlay, and some are not. The content provider may or may not enable support for AirPlay when using M3U8. For example, Apple (the company) uses M3U8 for the HLS format, which may use the H.264 AVC or H.265 HEVC codecs, with AirPlay support to some devices (not the legacy ones). Various video streaming websites may use M3U8 with other video properties, which may not support AirPlay.

In short, it depends on what you stream and from where. If AirPlay fails for your stream, then that stream wouldn’t be AirPlay compatible. But that is not because of M3U8 per se.

There may be apps for Apple TV that support your M3U8 stream (no AirPlay), and use their own parsing and decoding. I have no recommendations for that; you’ll have to search one what works for you.