Transcoding 4k to 4k not available, but 4k to 1080p works

Plex Media Server
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Server Version: 1.29.2.6364
Player Version: 4.95.2
CPU: Ryzen 5950X
GPU: RTX 2060 (Driver patched)
RAM: 128 GB ECC

Hi, I spent the last two days searching reddit and the forums, but I couldn’t find any solution or explanation to my problem in particular.

Maybe I don’t get it or I missed it, but my problem is not about transcoding 4k in general, nor do I want to start the discussion of if it makes sense to transcode 4k or not. I do bother transcoding 4k and it works fine when transcoding to a lower resolution.

I cannot figure out how to transcode 4k content to 4k with a lower bit rate then when using direct play. Transcoding 4k for example to 1080p or 720p works totally fine, and even direct play is not an issue, however I have multiple user that have 4k capable devices, but do not have the internet bandwidth for direct play. (I live in Germany and internet speed still is dogshit in a lot of places)

When configuring a remote streaming limit for the server (Settings / Remote Access) I do have some 4k options (25 - 40Mpbs) I can select. This leads me to believe, that transcoding to e.g. 4k 40Mbps should be possible. However in the player, no matter the device (Web Player, Google TV, Fire TV, Nvidia Shield), I can only select Direct Play or 1080p, but nothing in between. Why can’t I select for example 4k 40Mbps? My hardware should be more than capable and I can run multiple 4k to 1080p transcodes without any issues. Is this a bug or did I miss a setting or is it just not possible in Plex?

Thanks! I really appreciate any input, it is driving me nuts :smiley:

2

DirectPlay == Send the file exactly as it is.

This is the direct opposite of “Transcode” .

If you want to reduce the bit rate, you select from the available options for that player.

On my LG, the Android player app provides the following options for Remote streaming:

AndroidTV-4K
AndroidTV-4K816×612 69 KB

You will not get HEVC output from transcoding. Plex is not licensed for it.

3

Hm interesting, I am missing these exact options… I have Direct Play and then the next option is 1080p.

I know the difference between direct play and transcoding, but since direct play in 4k works fine, this leads me to believe that 4k playback works fine (from the client perspective) and since transcoding 4k to 1080p works fine, this leads me to believe that transcoding in 4k generally works also fine (on the server side). If my original file is in HEVC transcoding shouldn’t work at all, correct?

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PXL_20221126_234438747
PXL_20221126_234438747614×815 64.6 KB

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You can take a 2160p HEVC → 1080p, 720p, or 480p (on some clients)

Be careful please of which is the source and which is the target

The quality table you show there is correct.

  • 1 Play at original 4K quality.

  • 2 – 4., represent the most popular options for 1080p

  • 5 – 7, represent the supported options for 720p

6

Ah okay, so 2160p (HEVC) to 2160p is not supported?

7

Correct. I am almost 100% certain it all comes down to licensing.

I know it’s not a technical reason.
( It is trivial to do…I can spit out a FFMPEG command right now if I needed to for one of my files)

8

Ah ok, well that’s unfortunate… But thanks! So I assume if I convert my media files from HEVC to H264 using Handbrake or ffmpeg directly, then transcoding 4k to let’s say 4k 20Mbps should work fine?

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You can take your existing 2160p HEVC HDR → 1080p H.264 at any of the preset bitrates now.

Also please remember, you have some additional controls over bitrate-per-stream where you can actually impose limits lower (e.g. client requests 1080p 20 but you budget for 15, you can limit it that way on the server side and the client will see 1080p 15 Mbps.

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Yes, but I want 2160p HEVC HDR → 2160p (just with a lower bitrate then direct play), but this doesn’t work with HEVC, right? So converting my source file manually to 2160p H264 and then transcoding 2160p H264 HDR → 2160p should work right?

11

It’s been a while since I tried HEVC HDR 2160p → Something less than Original quality.

I know I’ll get H.264 AVC which is tone mapped from the HDR.
I don’t know the bitrate handling.

Let me check that now. BRB

edit: rebuilding my docker UHD library section now. sorry. takes 15 min

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Bit rate handling is not at the granularity you want.

  1. 1080p is capped at 20 Mbps (H.264 profile 4.0)
  2. The apps obey this because all transcoder output is H.264

I can’t remote test (hairpin turn) in my router – it’s a pfsense which is setup too securely for that.

I can limit my upload limit per stream (go look in Settings - Server - Remote Access)

The way to do it.

  1. Client requests original
  2. You limit the stream on the server side.
  3. The client gets the bit rate you set… using H.264 codec.

Untitled
Untitled756×600 122 KB

Sounds awkward but you can impose the limit from the server side.

13

Ok let me test that, that would be awesome :slight_smile:

One moment…

14

Hm ok nope :frowning:

I limited the bandwith:

image
image906×552 77 KB

But now I am not even able to select Direct Play anymore:

image
image581×845 77.5 KB

The “Show All” button doesn’t do anything btw… I am starting to get the feeling that this is maybe just bugged?

15

which client?

Click “Show All” … you should have “Original” option.

16

I am on the web client now, but no, “Show All” doesn’t do anything. If I remove the bandwith limit, I can do direct play in 4k again…

17

That’s the web client. It’s limited to 1080p 20.

It would be nice if it went better but they’ve never increased it
I think it’s a limitation of how much they can do in the javascripting in the browser – but that’s not my area.

Try ANY of the other players (android TV, etc… and you’ll have exactly what I showed you). I have a 2021 LG C1 here in my office for this.

18

The app crashes on start up now… But I think this is an unrelated issue, had this before, I have to reset everything.

I will get back to this tomorrow, thanks for the help so far! I will let you know if it worked.

19

When you try again, rather than forcing it, Set it to automatic.
Let it choose .

With the server enforcing a limit, you might just get what you want given automatic is the default.

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20

For what it’s worth, I’ve never seen a plex client option to transcode specifically to 4K. However, when watching 4K media in a browser that doesn’t support HEVC for example, letting it sit on “Convert Automatically” usually plays it in 4K H264. I agree that the quality selection granularity really should be fixed to include 4K options.

1 Like