4K movies don't play in Roku

[mskenny 8]

When I try to play a 4K video in Roku Emby, the spinner showing the percentage comes up but then nothing happens. You see the artwork for the movie, and the time at the top-right of the screen, but nothing else happens.  I've played 4K movies before with my Roku Ultra and it worked fine.  I tested using the LG app for Roku and was able to play the same movie that wouldn't play through Roku.  I tried different movies but no luck with any.  I checked for updates and am running version 4.1 build 41.  My Roku Ultra is model 4800X running Roku 14.5.  I've attached the Emby logs. Thank you.

embyserver.txt ffmpeg-transcode-084df6c6-35a3-401e-b5a0-05d83fc5a34b_1.txt ffmpeg-transcode-3640a3d9-8718-438c-8d5a-79f5da9f89aa_1.txt

[Luke 42077]

Hi, how did you configure the quality setting in the app?

[mskenny 8]

As seen in the app

[mskenny 8]

The Roku is on a wired network.

[speechles 2055]

TranscodeReasons=ContainerBitrateExceedsLimit

If you are on a wired network set the video quality to the highest possible. See if the media will direct play without transcoding. Because the bitrate of the item you are attempting to play is higher than was detected with the Auto setting it will cause transcoding. This is because the Auto setting isn't streaming. Using Auto will attempt to download packets from the server and see the time it takes. Then average the throughput from how it long it takes to attain all the packets. This might be lower than your network can actually support.

There is something about the way this is encoded that is causing ffmpeg to run into problems. This played on other players likely because it was direct playing. If you change the quality from Auto to the highest possible it should alleviate that problem.

You might also want to run that item through MKVToolNix GUI and see if it can correct any issues with the header. The Roku uses the MKV header to determine if and how it will play back the file. When the header is set incorrectly (to invalid values or done in a non standard fashion) the Roku and/or ffmpeg will act unpredictably. You just need to drag and drop the file into MKVToolNix and start remux. It will take literally a few seconds.

Edited May 6, 2025 by speechles

[Luke 42077]

13 minutes ago, speechles said:

TranscodeReasons=ContainerBitrateExceedsLimit

If you are on a wired network set the video quality to the highest possible. See if the media will direct play without transcoding. Because the bitrate of the item you are attempting to play is higher than was detected with the Auto setting it will cause transcoding. This is because the Auto setting isn't streaming. Using Auto will attempt to download packets from the server and see the time it takes. Then average the throughput from how it long it takes to attain all the packets. This might be lower than your network can actually support.

There is something about the way this is encoded that is causing ffmpeg to run into problems. This played on other players likely because it was direct playing. If you change the quality from Auto to the highest possible it should alleviate that problem.

You might also want to run that item through MKVToolNix GUI and see if it can correct any issues with the header. The Roku uses the MKV header to determine if and how it will play back the file. When the header is set incorrectly (to invalid values or done in a non standard fashion) the Roku and/or ffmpeg will act unpredictably. You just need to drag and drop the file into MKVToolNix and start remux. It will take literally a few seconds.

On the local network auto has no limit but I think a limit is coming from elsewhere. Doesn’t the app have its own limits for certain devices or formats?

[speechles 2055]

45 minutes ago, Luke said:

On the local network auto has no limit but I think a limit is coming from elsewhere. Doesn’t the app have its own limits for certain devices or formats?

The app will notice it is on the LAN and set the Auto limit to 40Mbit. What Roku considers their top streaming limit.

Otherwise the app runs a test to download 100KB of data.

If it notices the download speed is under 5Mbit then the Auto limit is 0.8x the download speed. As not to saturate the network.

If it notices the download speed is over 5Mbit it will run another download test for 1MByte of data. Then if it is over 35Mbit then 35Mbit is the new limit. Otherwise the limit is set at 0.8x the download rate of the 1Mbyte of data. This is all done to be conservative. To keep within what Roku considers their streaming limits. Now with people on their own networks and gigabit networks the Roku streaming limits can go out the window.

We stick within the Roku specifications to avoid Roku themselves giving us issues with publishing.

This is why we suggest setting a numerical limit rather than using Auto when on their own networks LAN. The maximum the Roku can go is 130-150Mbit (on a gigabit network) when using WiFi. With ethernet the Roku is limited by the 100Mbit port.

Edited May 6, 2025 by speechles

[mskenny 8]

Thanks, that fixed it. I've played 4K movies before without needing to change this.

[ebr 16169]

9 hours ago, mskenny said:

I've played 4K movies before without needing to change this

Hi.  The key is the bitrate instead of the resolution.  Your prior ones may have been below the threshold.

@speechlesI bet we can bump the default LAN rate up to 80 without much consequence...

[mskenny 8]

I had played "Stop Making Sense" without changing anything until yesterday when it didn't work. So, something changed besides the source file.  I saw this suggesting that Roku recently made changes that might have affected this; I don't have a Roku TV but I'm running the latest Roku software. Software update makes HDR content “unwatchable” on Roku TVs - Ars Technica

[Luke 42077]

HI, are you still having an issue with this?

[mskenny 8]

That setting fixed it. It's not very intuitive for users though. Thank you.

[Luke 42077]

We'll look at improving this. Thanks.

[thelanranger 11]

4k Roku sucks for this. The wired connection is actually only 100mb and is TOO SLOW to play 4k. If you connect with a wireless network with good signal you will get higher speeds than with the cable (counter intuitively) and the 4k issues tend to go away unless you play certain exceptionally high bitrate files on Direct Stream (like non-transcoded h264 or something).

This is not a problem with emby itself, it is a problem with the Roku hardware and them cheaping out and only putting a 100mb nic in the device. I've dealt with this on their device for a while and basically it's going in the garbage can and being replaced with another shield because of not just this but several other issues.