The Roku players in general are terrific streaming platforms, with some caveats. If your media is in the proper container and uses the proper codecs, then transcoding is unnecessary and they work great. If transcoding is necessary, there are currently some issues with HD Audio transcoding.
Roku has a limited number of video and audio codecs that are supported. This site https://support.roku.com/article/208754908-how-to-use-roku-media-player-to-play-your-videos-music-and-photos
has the full details, but basically they only support MKV, MP4 and MOV containers (although TS works as well), video has to be H.264/MP4 (H.265 with the 4K capable players) and audio has to be ac3/aac or a few other types. If you are using HDMI to an AVR, they will pass DTS audio though. However, right now no Roku will pass HD audio (Dolby TrueHD or DTS Master Audio).
The newest models (Premiere & Ultra) have issues with some users reporting either HDCP errors or audio "chirping". I have not experienced the audio issue, but have seen some HDCP issues with my Ultra. Roku is beta testing new firmware and my guess is they will have these issues resolved soon. The HDCP errors only seem to occur with a 4K TV, so connecting to a 1080 HD set should be fine. My Roku 4 has zero issues hooked to a Panasonic 1080 plasma.
We are hoping to have a resolution to the HD audio transcoding problem soon. Once that is resolved, Serviio will be including some new Roku profiles that should cover all the boxes.
If you are looking for a streaming player that supports the majority of codecs, and will passthrough HD audio, I only know of one player that has them all covered. That is the Nvidia Shield. It is quite pricey for just using as a media streamer, as it's built as a gaming platform. I've read on the forums that using it as a streamer works well, but the user interface isn't really designed for it and it takes more button presses to actually start playing your media. Not sure how big a deal that is, as I've never played with one.
Panasonic ST30 Plasma, Samsung JU7100 4K TV, Samsung UN24H4500 TV, Sony BDP-S3500, Insignia Roku TV, Roku 2 XS, 4, Ultra and Stick, Yamaha RX-V679 AVR.
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