If you use Infuse on your Apple TV to play HEVC/H.265 encoded 4K movies, it should not require transcoding. Infuse is capable of direct playing HEVC/H.265 encoded videos on the Apple TV, so the NAS does not need to transcode the videos.
However, keep in mind that the Synology DS220j is not a powerful NAS and may struggle with streaming high bitrate 4K video files, even without transcoding. You may experience buffering or stuttering during playback.
If you want a more powerful NAS that can handle 4K video streaming without any issues, you may want to consider the Synology DS218play or the DS220+. Both of these models are more powerful than the DS220j and are capable of streaming 4K videos with ease.
The DS218play is specifically designed for multimedia purposes and has a hardware-accelerated transcoding engine, which means it can transcode videos in real-time. However, since you are using Infuse, which supports direct playing of HEVC/H.265 encoded videos, transcoding may not be necessary.
The DS220+ is also a good option, as it has a more powerful CPU and can handle more demanding tasks, including 4K video streaming. It also has hardware-accelerated encryption and can handle up to two 4K video streams simultaneously.
However, keep in mind that the Synology DS220j is not a powerful NAS and may struggle with streaming high bitrate 4K video files, even without transcoding. You may experience buffering or stuttering during playback.
If you want a more powerful NAS that can handle 4K video streaming without any issues, you may want to consider the Synology DS218play or the DS220+. Both of these models are more powerful than the DS220j and are capable of streaming 4K videos with ease.
The DS218play is specifically designed for multimedia purposes and has a hardware-accelerated transcoding engine, which means it can transcode videos in real-time. However, since you are using Infuse, which supports direct playing of HEVC/H.265 encoded videos, transcoding may not be necessary.
The DS220+ is also a good option, as it has a more powerful CPU and can handle more demanding tasks, including 4K video streaming. It also has hardware-accelerated encryption and can handle up to two 4K video streams simultaneously.