JellyFin keeps transcoding even if TV support the file format (LG WebOS)

[Horo86]

I'm running JellyFin 10.9.11 on a Docker container hosted in a not powerful Linux machine (Archlinux), when playing HDR media on an LG B6 OLED TV running WebOS native app, the server transcode the media, even if the TV is capable of decoding it. 

Looking at the playback info, the reason for transcoding is "range not supported", which I think is about the HDR. The other 4K content direct play without any issue.

On the client, I've enabled the "Prefer fMP4-HLS Media Container" option.

How can I direct stream HDR content avoiding transcoding? Is there any known limitation in the WebOS app about HDR content playback?

Thanks!

[gnattu]

> "Prefer fMP4-HLS Media Container" option

Don't use this on LG TV because most models supports this badly

> Is there any known limitation in the WebOS app about HDR content playback?

It seems like that file is a dolby vision file in mkv container. LG TVs won't Dolby Vision in MKV which will make the server to remux it. Your server should not transcode it and I think it is not. Still need the ffmpeg log to make sure though.

> How can I direct stream HDR content avoiding transcoding?

You remux it into mp4 manually like this:


ffmpeg -i source.mkv -strict -2 -c:v copy -c:a copy out.mp4


You need -strict -2 to have the dolby vision configuration record being copied.

[Horo86]

First of all thanks for the clarifications and support!

> It seems like that file is a dolby vision file in mkv container. LG TVs won't Dolby Vision in MKV which will make the server to remux it. Your server should not transcode it and I think it is not. Still need the ffmpeg log to make sure though.

Here the pastebin of the transcode log (hope it is the log you asked for): https://pastebin.com/x4vbc7Wk
Where I can see if it is just a remux, or a transcode?
I suppose it is a transcode since the host CPU goes up to 80%.

[Fate]

First of all thanks for the clarifications and support!

> It seems like that file is a dolby vision file in mkv container. LG TVs won't Dolby Vision in MKV which will make the server to remux it. Your server should not transcode it and I think it is not. Still need the ffmpeg log to make sure though.

Here the pastebin of the transcode log (hope it is the log you asked for): https://pastebin.com/x4vbc7Wk
Where I can see if it is just a remux, or a transcode?
I suppose it is a transcode since the host CPU goes up to 80%.

Code:

Stream #0:0 -> #0:0 (hevc (native) -> h264 (libx264))
Stream #0:1 -> #0:1 (copy)

It's transcoding via CPU according to the log. I don't see the reason tho.
Apart from it not liking the hevc ....

If you look into the Admin->overview while playing the file on TV you should be able to see the transcode reason (click on the little i icon)

[Horo86]

If you look into the Admin->overview while playing the file on TV you should be able to see the transcode reason (click on the little i icon)

According to the playback info on the client, the reason for transcoding is "range not supported". Which I think is related to the media being HDR, since, playing instead a media using same MKV container, same 4k resolution, but SDR color space, transcoding is not happening.
However I cannot understand why, since the TV is capable of reading that same media if streamed via NAS DLNA without transcoding, or via USB drive.

[TheDreadPirate]

gnattu mentioned that it may be due to the container it is in and suggested remuxing to an MP4 container for testing. Since some players prefer/require MP4 for dolby vision.

[Horo86]

gnattu mentioned that it may be due to the container it is in and suggested remuxing to an MP4 container for testing.  Since some players prefer/require MP4 for dolby vision.

I tried right now to remux it as MP4 with the above mentioned command, but the behavior at the end is exactly the same as per the MKV. This is the reason for transcode while playing the MP4:

Code:

The media is being converted into a format that is compatible with the device that is playing the media.
Framerate: 24fps
24.5 Mbps TS H264 EAC3
Reason for transcoding
The video's range type is not supported

[Horo86]

Does anybody have an idea why this is happening?

[TheDreadPirate]

What version of WebOS is it running? The SoC specs state it supports 10-bit HEVC, so not sure why it is reporting it can't play HDR10.

[Horo86]

What version of WebOS is it running?  The SoC specs state it supports 10-bit HEVC, so not sure why it is reporting it can't play HDR10.

Here it is all the data:

TV Model: OLED55B6V-Z
webOS version: 3.4.2-570910
SW version: 5.70.40 (latest available from LG update)