I noticed this evening that the latest Plex 3.84.2 client for Samsung Tizen Smart TVs (my model is a UE50NU7400 running Tizen 4.0) always transcodes VC1 video streams to H264. These are standard Blu Ray rips, regardless of the audio codec or whether they contain subtitles or not.
The TV supports VC1, and if I copy exactly the same mkv files to a USB stick and play them direct on the TV, they works fine. I’ve tried with the latest PMS running on both MacOS and Synology ARMv8, and in both the Samsung Tizen profile XML file lists mkv/vc1/ac3 as a Direct Play target. But when trying to play them via Plex on the TV, the PMS log says that Direct Play is disabled (it isn’t). Bringing up the info screen on the TV, the ‘can direct stream video’ property is ‘false’.
Just a small update to this, I tested a few other apps and Synology’s DS Video and Emby can both play VC1 video fine on this TV, it’s only the Plex app which tries to transcode so it does certainly look like a bug in Plex.
I’m not sure what’s going on here… I’ve moved my TV into a different room and have it connected via ethernet now instead of wifi. I’ve also had to restart my Plex server and have re-installed the Plex client on the TV.
Anyway, it now seems that VC-1 is only transcoded when the audio also has to be transcoded. So if I play something like Harry Potter which is VC-1/AC3 then it direct plays fine, but with Back to the Future which is VC-1/DTS then it transcodes both the audio (because Samsung no longer supports DTS) and the video. As a quick test I used ffmpeg to convert Back to the Future to AAC audio with the same video stream. Now it direct plays as expected.
I also noticed another (perhaps related?) bug with subtitles. Embedded SRT subtitles are not displayed when the audio has to be transcoded. I did another test, this time with Return of the Jedi which has a DTS soundtrack and English SRT subtitles. It wasn’t displaying the subtitles, so I used ffmpeg just to convert the DTS to AAC, and now the subtitles are now working!
Please let me know if you need any of the server logs from these scenarios and I’ll post them here.
Sounds like it could be an issue on the PMS side. Logs would be great, as well as a sample clip of the original video (including all the audio codecs) would help debug the issue.
I can reproduce the VC1 issue using a 10 second clip of Back to the Future. The file contains two audio streams. If you select AAC in the client then it direct plays fine. If you select the DTS stream then the server decides to transcode both the audio and the video (should be just audio). Logs and link to the video clip are below.
I’ll have to spend more time on the subtitle problem. When I tried it now with a 20 second Star Wars clip, the subtitles were working fine even when the audio was transcoded.
Something I noticed, not sure if this helps, but I’m getting buffering on VC-1 videos too and have a Samsung The Frame (2018) TV which can handle VC-1. I just downloaded Plex for Tizen last night (April 27, 2019), and have some .mkv files on my NAS which is connected to my TV with a wired Gigabit ethernet connection. The Terminator is using MPEG2, and while watching, when I press the enter key on my remote then go to ‘Settings’, and then click ‘Quality’ for Video Quality, I have an option to ‘Play Original Quality.’ However, for T2, since it’s a VC-1 video, there is no option to ‘Play Original Quality.’ The TV can handle VC-1, so I’d imagine that option should be there. I’m new to Plex, so I don’t really know how to easily get log files, but if you need anything from me too, let me know.
I’m noticing my Synology setup is not able to handle the transcoding of VC-1 video files because it’s not powerful enough. I have a bunch of VC-1 mkv files and none of them are watchable because it keeps buffering every couple of seconds.
I don’t understand why the Plex app for my Samsung Frame TV is transcoding the file. I have it set up to use original quality.
I’m currently running Plex for Samsung 3.92.3; Tizen 4.0. Is there a way to update my app so that it doesn’t do any transcoding? Half of my library is unwatchable…
I had the same (or similar) problem. It turned out that it was the audio causing it to transcode. Samsung removed support for DTS audio in their latest TVs, so any files with a DTS soundtrack were transcoding not just the audio but the video too (Plex bug). To fix it, I used ffmpeg to add an AAC audio track to any files with DTS. Now my Samsung TV can use the AAC track and my LG TV can play everything without transcoding.
More recently I noticed in the latest Plex server for Synology there’s a bug which causes transcoding to occur when SRT subtitles are enabled. I rolled my server back to a slightly older version (1.15.0.659) and that fixed the issue. Some more details here.
Ahh thanks for the info and suggestions Stone. I was talking with my brother as he and I run two NASes from different locations and he was thinking along the same lines, where we’d have remux all our content to include, like you suggest, a fallback audio stream.
Am I understanding this correctly…everything should work but it just doesn’t due to bugs in the Plex app for Samsung TVs? Or is it that there just isn’t support for some audio codec and thus transcoding is required unless another audio stream is supplied?
I’m only asking because if I can avoid remixing another audio stream, I will hopefully wait for an update to the app. Not sure if the Samsung App Store is a PITA to get updates out there. If it’s some codec that is not supported then I guess I have no option but to add a fallback audio stream, at the cost of some size increase I’m sure.
Thanks again and it’s a real shame that these mega corps feel the need to create all these competing codecs. I can’t imagine the audio innovations are so drastic that they’re doing stuff no one else is capable of.
I think the problem was with the Plex server rather than the client. If you look further up this thread I provided a sample video clip and logs back in March but haven’t heard anything since then. Plex should be able to transcode just the audio and direct stream the VC-1 video (which even my basic Synology could handle), but instead it insists on transcoding everything.
