Subtitles and transcoding

General Discussions
1

I haven’t been able to find answers for these questions, so I’m asking them here. Sorry if they’ve been asked before.

  1. Does using subtitles mean that the video ALWAYS has to be transcoded - even with direct play or direct stream?
  2. Does it make a difference if the subtitle is embedded - as in an mkv-file - or does that mean that transcoding won’t be necessary (on account of the subtitle at least)?
  3. In regards to the need for transcoding when using subtitles, is there a difference in playing directly from the Plex Server-running computer’s web app and playing from, say, an Apple TV on the same local network?
2

I have no idea how your Apple TV is going to behave. My experience will include the devices in my signature.

MKV files will likely misbehave on your Apple TV (require a transcode) - that’s a guess really, but probably a pretty good one.

Embedded UTF-8 subs will likely Direct Play - if the MKV file itself will Direct Play. Some Plex clients (your devices using a Plex app) have an option to ‘Always burn subtitles’ (or something similar) and you’d want that off - or you force a transcode.

Sidecar SRT files - UTF-8 - are more likely to Direct Play for all containers and are absolutely required for MP4/M4V files - unless somebody knows something I don’t.

ANY other type of sub - image based, in particular - will be troublesome on most clients and I assume your Apple will be one of those.

3

Thanks for the answer @JuiceWSA
So, what I gather from this is:

  1. Using subtitles does not necessarily require transcoding.
  2. Apart from that it’s pretty much impossible to say anything definitive, as it depends on the video file container, whether the sub is embedded or not, the coding of the sub, the client/device and probably other factors as well.
1 Like
4

Yea, pretty much.

I would say an external SRT sub file in UTF-8 format is more likely to direct play across most devices. I can get an embedded UTF-8 sub track to direct play in an MKV file on all my devices, but I don’t own an Apple.

You should experiment a bit and find out what needs to happen across your devices for direct play subs and then stick with it.