The test condition:
HEVC (80+ Mbps), HDR, → 720p @ 4 Mbps. tone mapped.
Thank you. I will play with the clients I have and see if I can duplicate. I primarily watch at home and would generally not need to transcode at home. But I have a 4k HDR and a 1080p SDR both in my RV, so I am curious.
The closest I have right now is 77mbps, HEVC, HDR, using a web browser set down to 720p 4mbps and verified doing HDR-SDR tone mapping. No issues, CPU sitting around 10% total, no stuttering. I will keep looking and maybe see if I can find a download video that meets the 80+ spec. But no issues on my side so far.
From Tautulli:
- PRODUCT
Plex Web
- PLAYER
Microsoft Edge
- QUALITY
0.064 Mbps
- STREAM
Transcode (Throttled)
- CONTAINER
Converting (MKV MP4)
- VIDEO
Transcode (HEVC (HW) 4k Dolby Vision/HDR10 H264 (HW) 4k SDR)
- AUDIO
Transcode (English - TrueHD 7.1 AAC Stereo)
- SUBTITLE
None
I’m using a n100 with a bare metal install and it totally can transcode 4k. It maxes out at around 4-5 concurrent 4k transcodes with tonemapping enabled. I’ve tested it with 140gb mic Dolby vision files.
Sorry but this is not true.
The n100 is faster than the jasperlake, specially if you get one with ddr5. I had the n5105 and the n100 is much much faster, and it supports av1 transcoding.
Of course tonemapping is enabled.
I have the jasperlake here, I can transcode 4 GeminiMan (187 Mbps 59.94 fps) to 20 Mbps without it blinking.
EDIT: I found it. Thank you. I stand corrected.
It’s an AlderLake, with AV1 decode, with about the performance of an i5 CPU.
While the original issue still hasn’t been resolved, I want to let everyone know that I purchased an Arc A380 and passed that through to my VM. I no longer have the HEVC transcoding artifacts when set to original quality.
I have moved my transcoding over to my UHD 770 (i9-14900T) from an Nvidia A2 after extensive testing the video quality output. Testing on phones and Rokus it seemed to be great!
Last night I tested on a new Fire Stick and it didn’t look so good. Not unwatchable like previous generations of QSV but certainly not Nvidia! Kinda disappointing. I do like saving the few watts of power not having the additional card in my server but I don’t want subpar video streams.
I’ll reach out to my Samsung user and see if they have noticed any compression artifacts.
Does this have anything to do with subtitles? All I’ve found is that it’s the same as described in a post from years ago(Artifacting when using hardware acceleration transcoding with integrated intel graphics), and after all these years it looks like they still haven’t completely solved the problem, and may not even know what’s causing it!
I wonder how long they want to spend on fixing this again.
I am using Windows 10, Celeron N5105, graphics driver version 31.0.101.2114
It does seem to have significantly less artifacts when subtitles are turned off. For a while there, I thought that this issue had gone away after fixing the local network and bandwidth limit settings - but that must’ve been a different issue. I’m still having the same trouble on my Samsungs.
At this point I’ve pretty much given up and have been dealing with it because even if the problem is determined, a fix is likely not going to happen.
Yeah, when burning subtitles quality gets pretty rough at times, I particularly notice it during scene transitions. I’m running on a Core i7-12700H on Linux/docker, so probably not the same as that old Windows bug. I’m not really sure if it’s specifically subtitles as I use a Shield TV Pro which will direct play basically anything if it doesn’t have to burn .ASS subs. I’m hoping that the eventual transcoder update that includes hardware subtitle burning will improve things, gonna just deal with it until then.
I’ve purchased a 10th gen NUC for testing and will be setting it up the exact same way for a side-by-side comparison. I should have it ready within the next few days.
10th Gen i7: Intel UHD
11th Gen - 13th Gen: Intel Iris / Iris XE
Good news. I’ve set the Gen 10 NUC up next to my Gen 13 with an identical deployment - Proxmox with plex running in an LXC container. Configurations have been matched between the systems, and both are pointing to the same media source.
The Gen 13 NUC has Alder Lake-P Integrated Graphics (Intel Iris XE)
The Gen 10 NUC has Comet Lake UHD Graphics
So far, the 10th gen NUC does not have the same quality issues as the 13th gen in dark / action scenes. Here is a short video with a side-by-side comparison. Around the 45 second mark, you should be able to see the fingers get blocky (13th gen) - this does not happen on the 10th gen system.
I will test with subtitles on my Samsung TV next.
Here is a still image from another piece of media. This is a side-by-side quality comparison between the 13th gen (left) and 10th gen (right)
*Edit, download and open the image locally to avoid web compression to see the actual quality.
Can confirm artifact issues with UHD 770 on 12900K. Every other minute or so I get a few choppy frames. How is this not solved yet?
The hard part is determining whether this is a hardware vendor issue (firmware) or a Plex issue. The quality problem with transcoding 265 content is only apparent on 11th gen (and later) nucs with Intel Iris / Iris XE, and Intel chips 12th gen (and later) with the UHD 770.
@ChuckPa / @chrisallen – can we get official acknowledgement of an issue here?
I’m honestly surprised this hasn’t been more prevalent of an issue considering (assuming) this has been around since hardware release 3 years ago.
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I cannot confirm or deny the issue – JUST YET 
My NUC8-i7-HVK (i7-8809g) is getting a little long in the tooth.
I ordered a Dragon Canyon NUC (yes a few new ones were still hanging around). i9-12900 . I should have it Monday or Tuesday.
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I also notice way more degradation on videos with ASS subtitles. I got a 12900K with UHD 770 just for Plex transcodes, and now I am getting visual degradation on it, just like OP explained.
The degradation is not that noticable on an Android tablet, but Samsung TVs look straight up horrible.
My NUC12 arrived and is online.
I cannot confirm the reported issues, THEREFORE …
I need logs and sample files…
I also need the XML of the files because while 3-4 Mbps looks great on a phone, it will absolutely look like S*** on a large screen TV (projection effect)
Followup:
Forcing transcode to 20 Mbps, with tonemapping, and audio conversion, on AlderLake (12th Gen). No difficulties so far.
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You should try playing something with embedded ASS subs, I get almost 100% success rate reproducing the problem with almost any anime.
OP explained it well in the original post, comparing NVENC and QSV. I made similar comparisons on my server, and noticed the same results. Of course I did not just go into this looking for issues, I have first seen the pixelation on every other frame where there was movement. I switched from a GTX1060 to UHD770, and the difference in quality is very apparent.
I cannot provide any logs, since there is no errors, just pixelated transitions on random frames.
