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Level 8

MKV audio delay with Roku Media Player (works with MP4)


Roku Media Player introduced an audio lag (audio lags behind video, variably from 200-600ms) ever since the 9.4 Roku OS update.

I have a TCL 55R615 Roku TV (Roku model 7120X) running the 9.4.0 Roku OS (build 4190-30).

I store all my video files on a WD-EasyStore hard drive, connected to a USB port on the TV (using a USB 2.0 bridge, because a TCL TV won't recognize a USB 3.0 device).

Ever since the 9.4 OS upgrade, all my files played on the Roku Media Player have an audio lag of variable length.  

All my files are wrapped in a MKV file container using MKVToolNix.  They've all worked fine for months, until this last patch.  

I've done all the basic troubleshooting steps for audio and video lag mentioned in these forums and others across the internet.  

My video codecs are either h.264 (AVC) or h.265 (HEVC).

My audio codecs are usually AAC 2 channel at 196k.  

Since the lagging started, I started using different codecs hoping to fix the problem.  I've tried Dolby Digital (AC3) and Dolby Digital Plus (E-AC3) [2 and 6 channels, and different bit samples], even tried PCM.

I tried different USB drives, and nothing worked.  The lag was there.

Streaming Netflix has no audio problems, it seems to be solely Roku Media Player.

I decided to wrap some of my movies and shows in a MP4 container using FFMPEG, and play them on the Roku Media Player.  They had no issues.  All I did was demux the MKV files into their respective audio and video tracks (with FFMPEG), and re-wrap them in an MP4 container (with FFMPEG).

So, I know there is not an issue with the Roku Media Player "reading" or "interpreting" the audio codec, because the codec (audio tracks) are the exact same from my MKV to MP4 files.

I don't want to reconvert all my MKV files to MP4 to get them to work with Roku Media Player.  They all worked fine prior to the 9.4 Roku OS upgrade.

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6 Replies
Level 14

Re: MKV audio delay with Roku Media Player (works with MP4)

Make sure you contact Roku directly about this:

Chat or Email:   (choose setup/ultra/other/need more help)

or message @RokuChris (he codes RMP and handles the RMP beta) and/or @RokuDanny-R 

Level 8

Re: MKV audio delay with Roku Media Player (works with MP4)

Well, I found an interim solution.  I spent 3 bucks and got the PlayUSB app.  It plays my MKV files fine, with no audio lag.

Also worth mentioning is that my Roku Ultra, with the 9.3 OS, also plays the MKV videos without the audio lag.  

Seems the RMP on Roku OS 9.4 has a bug.

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Level 21

Re: MKV audio delay with Roku Media Player (works with MP4)

That's interesting.  Does the Play USB channel/app use the old style UI?  It's pretty much impossible for a channel/app to have a bug when it comes to playback since all it does is tell the firmware what to play.  I'm wondering if the bug is in the new video player component vs. the old.

Level 8

Re: MKV audio delay with Roku Media Player (works with MP4)


I don't know if the PlayUSB app has the old style UI.  Its Version 5.2 build 823, if that helps.

My Roku Media Player is Version 5.4 build 4


OK, some bad news.  I played a movie in MKV format on the PlayUSB app, and it had the same lag.  The audio trailed the video, not bad enough to where it was unwatchable... but definitely noticeable.

After the movie was over, I used ffmpeg to create a new MP4 file, and it worked flawlessly on PlayUSB.

ffmpeg -i inputfile.mkv -c:a copy -c:v copy outputfile.mp4

So, it seems that stating PlayUSB fixed the problem was premature.  

My options right now are to wrap everything in MP4's, or plug my Roku Ultra (with Roku OS 9.3)  into my Roku TV and use it to play movies/shows off my external drive.


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Level 14

Re: MKV audio delay with Roku Media Player (works with MP4)

Again, make sure you report this directly to Roku as previously advised...

Level 8

Re: MKV audio delay with Roku Media Player (works with MP4)

I will do it tomorrow, thanks!  I'll also post what the outcome is.

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