How to stop transcoding 4k

[BushySushiPanda]

Server Version#:1.15.5.994
Player Version#:2.17.9 Plex for Vizio and 7.1.2 Plex for Android on Fire TV 3rd gen

Plex server running on Windows 10. When playing 4K content (files are HEVC x265 10bit HDR), a 3rd gen Fire tv and Vizio tv app always play transcoded video (4K HEVC Main 10 HDR) to 4K (H264)
I have a tv with built in Amazon Fire TV that will play same files as direct play.

How do I stop server from transcoding to the other devices? Both Amazon Fire TV and Vizio tv support 4K HEVC x265 video.

[TeknoJunky]

start with;
change the audio stream and/or disable subtitles

otherwise we are going to need a lot more details.

like details of the particular content video/audio codecs, subtitles enabled/disabled, what the server status screen shows

may or may not help see also @ Plex, 4k, transcoding, and you - aka the rules of 4k - a FAQ

[FordGuy61]

Playing 4K HEVC media is broken on at least some FireTV devices.

I’ve an AFTV Cube (2018) which supports Main 10 Profile Level 5.1 according to the tech specs.

However, any 4K HEVC video in the High Tier (ex: Main 10@L5.1@High) transcodes.

Video using the Main Tier direct plays.

The problem is that 4K HDR movies are all in the High Tier, so they transcode.

I’ve no idea if the problem is due to AFTV device limitations or an issue with Plex software.

However, it is frustrating and it would be nice to get it fixed.

I’ll grab PMS & client logs later today or tomorrow and add them to the thread.

---

There is another problem with 4K playback on the Cube. I do not know if it happens with other AFTV devices.

The AFTV cube will scale 4K video to 1080p. PMS reports direct play. The scaling occurs on the cube.

This happens when the AFTV video resolution is set to Auto. The Plex pre-play screen is in 4K. When playback starts, the video is scaled to 1080p. When playback stops and Plex returns to the pre-play screen, the video is again in 4K.

The workaround is to set the AFTV Cube video to 4K instead of Auto.

No idea if this happens with other AFTV 4K capable devices. My other AFTV devices are older and do not support 4K playback.

[BushySushiPanda]

Thanks. I will look into the Auto setting and try 4K.

To TeknoJunky, I have changed audio to EAC3 5.1 and no subtitles, forgot to add that to original post.

[TeknoJunky]

in the server logs it should give an indication as to why transcoding was decided, it sounds like it could be what fordguy posted.

[BushySushiPanda]

Thanks,
I got logs, but forgot to turn off verbose logging. I’ll try to get updated logs and post later.
I agree, sounds like same issue fordguy described.

[rory_o_hotmail_co_uk]

Hi Guys

I have had a few looks on the Forum and cannot find the answer for my specific question… so here goes.

I cannot play 4K Movies that i have on my server through My 4K Projector.

I run an Amazon Fire 4K HDR Dangle Box (which does display at 2160 when Its on), and an Optoma UHD51 projector. I use an EX Data centre Poweredge R710 and everything is hard wired with CAT6 in my home network. Plus I use Optical fibre for audio.

I dont know what logs i need to attach but i have attached a full days logs… I tried to run a 4K movie after 9pm, twice. It was “Age of Ultron”.

I get the error that the Server is not powerfull enough, and it crashes, then i relaunch and start it as direct play… then it just buffers forever and crashes.

Any ideas on what i can do?

Plex Logs.7z (208.0 KB)

[FordGuy61]

Which AFTV device do you have? The 4K stick, the Cube, the Gen 3 Pendant, something else?
See AFTV Tech Specs.

Edit: Found it in the logs. You have the AFTV Gen 3 (pendant).

Do not choose a TrueHD audio stream. It is not supported on AFTV devices and will transcode. Use a Dolby Digital (AC3) or AAC audio track if possible.

Do not enable subtitles while testing. Subtitles can force video transcoding under certain conditions. Leave them off for now.

Turn off verbose logging. Debug logs only. (PMS Settings -> General).
Play the movie again until the problem occurs.
Pull a new set of logs and attach the entire zip file (PMS Manage -> Troubleshooting).

Also, in the AFTV Plex client, set Display Information = On.
During playback, pull up the on-screen controls (tap the bottom of the ring on the remote or pause the video).
What is displayed in the upper left corner of the screen? If the video or audio is transcoding, what is the reason provided for each?

[rory_o_hotmail_co_uk]

Hi Ford Guy

Thanks for helping

I have attached some logs with verbose loggin off, it will be the most recent part of this logging zip. Plex Media Server Logs_2019-05-30_06-24-17.zip (4.4 MB)

So once i first played this movie affter optomising, it was ok! it said "Direct play in the on screen information.

When i went back to it to play again, it had to transcode. it now says “Unable to direct play as the media is not compatable with the device” i do not follow why its changed its mind.

Audio is not trying to transcode.

Plus this is the settings for the 4K movie which last night I Optomised through the inbuilt optomiser in plex.

[FordGuy61]

Thanks for the information.

From the pic you provided: Bitrate 24485 kbps

From the logs you provided:
May 30, 2019 06:23:39.500 [18092] DEBUG - Fantastic Beasts and Where to Find Them - video.bitrate limitation applies: 24485 > 20000

So something is telling Plex the AFTV cannot play video above 20 Mbps.

Please check the settings in the Plex App on the AFTV Gen 3. Are they any different than these?

Video Quality
   Adjust automatically = Off  <-- Can cause transcoding if on.
   Home streaming = Maximum    <-- Change to Maximum if different
   Remote streaming = Maximum
   Play smaller videos = On
Advanced
   Passthrough = HDMI

If you change any of the settings, please play the movie again, see if it still transcodes, and grab a new set of logs.

Thanks.

[rory_o_hotmail_co_uk]

Hi Ford Guy

I have no idea at all what could be effecting the bitrate

What can effect the bitrate internal on the Fire TV device?

I have changed the Audio pass through, this was disabled, it now runs on HDMI.

Still Transcoding sadly.

please see attached logs of the same movie playing, for around 10 seconds.,
Plex Media Server Logs_2019-05-30_08-18-06.zip (4.3 MB)

[FordGuy61]

Short Answer:

Your FireTV is not going to direct play your Fantastic Beasts movie, or any other 4K H264 movie with a bitrate above 20 Mbps.

Edit: The video transcodes to 4K H.264, so while you are losing a bit of quality, you are not losing any resolution.

Long Answer:

In addition to your logs, I did some testing with my FireTV Cube.

The tests indicate the Plex app on the FireStick cannot play 4K H.264 video at bitrates higher than 20 Mbps. It will happily play 1080p H.264 at 80 Mbps. However, 4K H.264 above 20 Mbps transcodes.

I created several 3840x2160 H.264 videos at varying bitrates (I ran an existing video through Handbrake and manually specified the bitrate).

All the videos at 20 Mbps or lower direct played.

All the videos above 20 Mbps transcoded.

For the transcoded videos, the log file contains “video.bitrate limitation applies: X > 20000” (where X is the bitrate of the transcoded video).

I created two optimized versions of the 25 Mbps file. The ‘Original Quality’ version still transcoded, as it was 3840x2160 at 22 Mbps (which is expected). The highest quality custom version I could create was Universal TV, 20Mbps, 1080p. The resulting file was actually under 6 Mbps, so it easily direct played.

To summarize, the best I can tell, the Plex app on your FireTV Gen 3 has a bitrate limit of 20 Mbps.
Therefore, it cannot direct play your copy of “Fantastic Beasts…” as the movie has a bitrate of ~24 Mbps. In addition, the Optimize function in PMS does not provide the capability to specify specific bitrate for 4K movies (just “original”).

So, if you want to watch movies such as “Fantastic Beasts…” in Plex you need to either (a) manually transcode the movies to a bitrate under 20 Mbps (via Handbrake or similar tools), or (b) find a Plex client that will play 4K H.264 movies with bitrates higher than 20 Mbps.

---

Notes:

1. My FireTV Cube will also not direct play any 4K HEVC HDR movie in my collection. I’m still running tests, so don’t know if it is a bitrate or other issue. Just a heads up about it.

2. For my test files I used the Jellyfish Bitrate Test Files. I ran one of the files through Handbrake if I needed a bitrate/resolution not available on the web site.

3. I also have a Nvidia Shield. It happily direct played the 180 Mbps 4K H.264 Jellyfish file. The 200 Mbps H.264 file transcoded. It also direct plays 80 Mbps 4K HDR movies (I haven’t tried anything above that bitrate).

4. No idea if a Roku, AppleTV, or other Plex client would work. I don’t have any of those devices with which to test.

5. I use the terms “4K,” “3840x2160,” and “UHD” interchangeably. I’m always referring to videos with a resolution of 3840x2160.

[FordGuy61]

@rory_o_hotmail_co_uk

So once i first played this movie affter optomising, it was ok! it said "Direct play in the on screen information.

When i went back to it to play again, it had to transcode. it now says “Unable to direct play as the media is not compatable with the device” i do not follow why its changed its mind.

On the movie pre-play screen, navigate to, and select, the “More” button. You should see an option that says “Pick Version.” This will let you pick either the original or the optimized version of the movie.

[rory_o_hotmail_co_uk]

Hi Ford Guy,

Your help has been so valuable to me, thank you. I will take this file and run it through handbrake at a bitrate just lower than 20,000 and see how it fairs out. I shall also try the Jelly fish files and report back to see if for some reason it gives different data from what you have just found out.

I think I will ask Amazon to explain why this is the case with my unit, Its abit odd that its said to accept 30,000 and in this case it does not.

This is a sad moment for me, I decided to cheap out and buy the Amazon Fire TV in Lou of the Nividia Shield, not expecting to have any such bottlenecks.

Thank you for your help FordGuy, and if i find out anything from my trial and errors i will let you and the community know.

EDIT - Look back through the developer specs. i have found the reason why…

My file is a H.264 file, If I transcode to a h.265, i should achieve the Bitrate.

EDIT 2 - I have tried the JellyFish files… i got all the way to 110Mbps and no transcoding on 1080P… the problem i had then was my Ethernet was limited to 100Mbps due to its design.

The Client here should only be able to accept max 20Mbps from a H.264 encoding yet I went to 110Mbps…

I dont understand this at all, it must have to do with the resolution, as i tried to play the 120mps 4K UHD and it needed to transcode. (as expected, but i wanted to try anyway.)

[rory_o_hotmail_co_uk]

After many hours recoding the same file, i have managed to get a fully Direct stream.

4K UHD running at 20,000 Kbps…

HOWEVER, now i get the “Connection to server not fast enough” and a buffering ring for some time.

My Amazon Fire Gen 3 Pendant is connected via Ethernet Cat6 cable, but i think the unit is limited to 100Mbps its not Gigbit. I have played 100Mbps rater 1080P files perfectly fine. (110Mbps did buffer abit)

So my question now is, why is there a bandwidth issue for Direct play 4K?

Again i have atached logs below for any insight into this. Plex Media Server Logs_2019-06-01_06-25-08.zip (4.4 MB)

[qureshiiu]

You can also change the default / master settings for Remote and Local streaming quality to ORIGINAL that will force the player to play the file in its native resolution 4K , HDR ,1080 etc. downscaling or conversion won’t happen.