Roku Device Features, Settings & Updates

Help configuring Roku device settings, using Roku OS features such as screen mirroring, adjusting display type and audio settings, using Guest Mode, and assistance with software updates.
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Level 8

TCL-55R617 Plex some videos with lip sync issues

Some of my videos have lip sync issues others are fine. The same videos played on W10 desktop using VLC perfectly. This is not due to the latest Roku update, I have finally got around to reporting it. These are mkv videos, 1080P, AC3 stereo, SRT subtitles and play direct.

Device: 7120X TCL55R617 TCL Roku TV

Serial No. - YS00CS132630

Software - 9.4.0 - BUILD 4190-30

Device ID - FV291C132630

Plex 6.7.3.6761-f944ccaa5

 

So update of Roku TV to 4200-30 did not fix lip sync issues, on some videos forcing transcode fixes, on others it just makes it more out of time. Should I continue to post about this issue here or at the Plex forum?

5 Replies

Re: TCL-55R617 Plex some videos with lip sync issues

I thought I was seeing things. Glad to see I'm not alone in this. Please fix asap!

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Level 8

Re: TCL-55R617 Plex some videos with lip sync issues

Can I suggest you open a ticket with Roku about this. I did a couple days ago and they sent me some generic things to try (remove Plex, update Roku TV, restart Roku TV, add plex and try again). I still get the same results. 

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Level 8

Re: TCL-55R617 Plex some videos with lip sync issues

You're not alone in this.  I have the exact same TV as you, same firmware. The only workaround is to disable DirectPlay in Plex (either the client or the server). This will not trigger transcoding, so quality will not be affected: it will re-mux the file into a different container that is probably easier for the Roku to handle.

 

Note: this bug only shows up for me when using my soundbar (plugged in via HDMI). Using the TV speakers works with DirectPlay enabled.

You can check out this thread in reddit where it was discussed: https://www.reddit.com/r/Roku/comments/k8g7i6/audio_delay_with_roku_94_only_happens_on_plex_and/

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Level 8

Re: TCL-55R617 Plex some videos with lip sync issues

Yeah it works, for me it changes the audio to MP3, not as rich and full a sound as AC3 and also the volume is reduced. IMO definitely just a work around. I'm playing audio from the TV's headphones jack to a small amplified set of speakers, normally is good enough, but with MP3, not so much. 

I does seem to be a problem in the Roku decoding of AC3/eAC3 and not Plex. Plex just hands the container video to the hardware (Roku TV) to play after transcoding and or re-muxing if deemed necessary by the client. All my other Plex clients as well as VLC (PC) play both perfectly. 

I have a video in which mediainfo says there is 16 bit AC3 and it plays perfect thru Plex/Roku, whereas the one(s) that show the problem don't list 16 bit AC3 depth in the mediainfo. This is a super small sampling though so can't determine if this is the problem (or the only problem). 

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Level 8

Re: TCL-55R617 Plex some videos with lip sync issues

I don't think it's a Plex issue, we're just "lucky" that Plex has a feature which allows us to workaround the problem.

When using Roku Media Player, I get the same sync issue, but there is no way to have re-mux the file in a different container.

Hopefully they fix this soon, I'm sure there's a bunch of people out there that don't know about the workaround, or are just not using Plex.

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