Server Version#: 1.32.7.7621
Player Version#: 5.72.3 (platform 6.3.3)
For some reason my LG TV is deciding to transcode this movie even though I’m using PGR subtitles. If I had to wager a guess why it’s because it’s foreign audio and the Plex software is automatically turning on the PGR subtitles that also exist without me explicitly selecting those subtitles. This however shouldn’t happen because I have subtitle mode as “manually selected.”
So this feels like a bug in the Plex software.
As an aside: PGR subtitles SHOULD work on this TV as this LG UHD tv supports it (and the LG Plex patch notes indicate it should too), but they haven’t for many months which is why I have been going the SRT route recently. I would appreciate if the Plex devs take a serious look at subtitle support on these TVs.
Does the audio still transcode if subtitles are turned off?
With the Plex LG app, if the media is direct streaming, such as when audio is transcoding, enabling any form of subtitle results in video transcoding.
If the TV is running webOS v3, then enabling PGS subtitles results in video transcoding.
In addition to transcoding the video, Plex Media Server is burning the subtitles into the video stream (adding them to the video frames instead of sending as separate track). The burning process uses the CPU, even if the video is using hardware accelerated transcoding. The burning process is also single threaded, so in cannot take advantage of multi-core CPUs. If the CPU is not fast enough to burn subtitles in real time, the end-user will experience buffering.
According to the TV tech specs, it does not support TrueHD or DTS audio formats, so those will be transcoded by Plex Media Server.
PCM is listed as a supported format. Not sure why it is transcoding.
Check the Plex LG app settings. Make sure both Direct Play and Direct Stream are enabled.
I do see that the audio transcodes with the subtitles off. However, video does NOT transcode. I’m not sure I understand why PCM audio + SRT subtitles = video needs to transcode, I’d think only the PCM would need to transcode by itself?
It is not just PCM audio. It is any audio that transcodes. You will have the same issue with TrueHD and DTS audio.
It is a limitation of the streaming protocol used between Plex Media Server and the TV. It has existed at least since I bought my B7 about six years ago.
It has been mentioned on the forum a few times by Plex employees. I don’t have a link handy to one of the old posts.
The issue is that when direct streaming, if subtitles are sent as a separate track, they will be out of sync with the video and audio. Therefore, Plex has to burn them into the video stream.
The limitations of the Plex SmartTV apps are one reason many people use streaming devices such as Firesticks, Nvidia Shields, etc.
I acquired a Nvidia Shield Pro several years ago primarily due to the limitations of the Plex SmartTV app. The Shield Pro direct plays everything in my library. It also passes lossless audio to my receiver. I’ve the 2015 model and it is still going strong. The current model, updated in 2019, adds support for Dolby Vision video.
