Solving playback issues

[stevedoreNJ]

  I've recently ripped some DVDs to .MKV format to put on my media server.  The subtitles work fine when I view the .MKV files with VLC on my Macbook, but not on the media player on my Roku Ultra.  

  Am I overlooking something, doing something wrong, etc., or is this just the way it is?

  I use MakeMKV to create the MKV files from the DVDs, and subtitles have worked OK with several movies in the past.

[renojim]

@atc98092can tell you more than me, but I don't believe any kind of subtitles embedded in MKVs are supported.  I've always used separate SRT files.

[atc98092]

DVD and Blu Ray discs use an image based form of captions. On DVDs they're called VOBSUB, and Blu Ray uses PGS. Neither type of caption is supported by Roku devices. Only text based captions are supported. These text based captions be be embedded within the container, such as EIA-608 captions from OTA broadcasts, or external text files, such as the SRT format. There are programs that are supposed to be able to extract the image based caption and save them to an SRT file, but I've never successfully used them.

The only files with embedded captions that display the captions successfully on my Roku devices are OTA recordings that I've saved in the TS format. These files could also be saved in the MKV container, but my video editing software strips captions out when saving to MKV, so I stick with the TS container. But several different containers are capable of keeping text based captions within them.

[Kryten79]

ROKU, Please add support for embedded subtitles in MKV files as they are so common.

[atc98092]

@Kryten79 Roku does support subtitles in MKV files. But only if they're text based. Image based captions (which are used on almost all DVD and Blu Ray discs) are not supported. I don't know the complexities of decoding image based captions, but it might not be possible with the hardware Roku uses. I simply don't know the answer to that.

MKV is a container, and can hold almost any video and audio codec and caption style. Same as MP4, AVI, TS/M2TS, and others. Just because the file extension is a certain three/four letters, you can't determine what is within the container.

[Kryten79]

Yes, thanks for the ridiculously  fast reply.  I rip my blu-ray dvds to the NAS as MKV with embedded subs.  I bought a new ultra 2022 a few days ago and love the ATMOS sound and 4K video.  I was just surprised I can't get the subtitles to display.  The Roku Ultra should have enough horsepower, but I do realize MKV is a container and many codecs  can be used.

All my files play fine on VLC on PC, but that's a different beast with a different purpose.

[Michelle3]

@Kryten79  Do keep in mind that DVD and Blu-ray are two completely different formats. 
~ Jordan 

[atc98092]

Yes, VLC can play virtually anything on any platform. But they have specifically said they would not be writing a version for Roku, as the RokuOS is not compatible with the programming language they use. 

It's possible that it might work on FireTV, but the FireOS is not standard Android, so it's possible it won't work. It is available for iOS and Android TV, but doesn't appear to work on Apple TV. I know it works on my Nvidia Shield players, which runs a version of Android TV. Amazon's FireOS overview does say that most Android apps will run, so perhaps it's possible.

Back to the Roku, you have a few options to get captions from your ripped media. First and easiest is to install Plex server on a computer on your network. Plex has a great user interface, and is capable of decoding image based captions and burning them into the video stream. But that requires a computer with a fair amount of power to transcode the video, especially if you're decoding 4K ripped media. Another option is a DLNA server such as Serviio. It too can decode the captions and b u r n them into the video stream, but it has the same computer power needs. Not mega powerful, as my primary media PC is "only" an i5-6400 and 8 GB of ram. But not anything really lightweight.

The only option that would not require burning the captions is acquiring a text file with the captions, which is usually in a format called SRT. You can download SRT files from a number of online sites, most all of which are free. Here's a list of some available sites. You can also use a program that can open your video file, decode the captions, and save them to an SRT file. The problem with both of these methods is the time it takes to find and download the correct SRT file for your media. And sometimes there simply isn't a matching SRT file in any of the repositories. And opening each media file to extract the captions would also be time consuming.

[Crevice9]

On my Wi-Fi network I use my PC as a server for ROKU and as long as Windows Media Player and locations for Video libraries that I add are scanned they can be accessed using ROKU Media Player.

I have not figured out the correct way to get subtitles to display every time. I use Handbrake to convert the video files to mkv and have separate srt files in the same location. If I remember correctly, I can add srt files into Handbrake creating a separate track that can work but I can't remember.

Why are srt subtitles not showing up every time in ROKU?

[atc98092]

@Crevice9 Make sure the SRT file is named exactly the same as the video file, right down to any punctuation and spaces. For an example, I have one that I just ripped that didn't have a captions track so I downloaded an SRT file but it had a different name and wouldn't work on any player, Roku or otherwise. I renamed the file and it worked immediately.

"The Quiet Man (1952).MKV" - "The Quiet Man (1952).SRT"