Plex HW Transcoding does not work for some files

OS: ElectricEel-24.10.1
Plex installed using stable train through app discovery.

Hi,
This isn’t really a big deal, but I just wanted to reach out to see if anyone else has encountered a similar issue.

I have encountered some weird behavior with Plex and QSV HW transcoding seeming to not work on random files in my library. The technical specs between files that do work and don’t work are the same and I don’t have any issues with this exact same hardware with hardware transcoding on Windows.

The thing that’s been baffling me is that with plex, even if the hw transcoding can’t be used to decode the files, it is always used for encoding the streams; but for some reason, on some files it doesn’t even seem to use the iGPU for encoding the video!

I haven’t found any correlation between files that do work and don’t work. I did realize in the end that the hw transcoding issues only seem to be occurring when testing with a browser? In any case I’ll probably just chock this up to browser weirdness.

Perhaps the specific files use an oddball codec that the Linux drivers can’t handle, perhaps the files are actually broken but the Windows version handles it gracefully in the background, perhaps it’s a bug.

But instead of further speculation, check the log files.

Linux can definitely handle the codec as another file from the same season with the same mediainfo hw transcodes fine.

Regarding logs, I noticed these errors crop up whenever I attempt to play affected files.

[Req#18675/Transcode/kmpjuo3tz5kcyu66fegwyss7/b13d8fc2-6a0f-4f25-bb63-789a8f5188f4] [hwupload @ 0x7fd4b0e66780] Failed to upload frame: -22.
[Req#18677/Transcode/kmpjuo3tz5kcyu66fegwyss7/b13d8fc2-6a0f-4f25-bb63-789a8f5188f4] Error while filtering: Invalid argument
[Req#1867a/Transcode/kmpjuo3tz5kcyu66fegwyss7/b13d8fc2-6a0f-4f25-bb63-789a8f5188f4] Failed to inject frame into filter network: Invalid argument
[Req#1867d/Transcode/kmpjuo3tz5kcyu66fegwyss7/b13d8fc2-6a0f-4f25-bb63-789a8f5188f4] Error while processing the decoded data for stream #0:0

I can’t find much about this error, but there’s a recent reddit post that is essentially the same:
https://www.reddit.com/r/PleX/comments/1hhun44/plex_transcoder_sometimes_fails/

Not sure how to further troubleshoot this other than explore the browser angle some more.
Do some specific browsers work where others don’t? Try ones that use different rendering engines if you can.

After some more tested I did find that everything worked properly when I disabled the PGS subtitles. My current thinking is that something with the PGS subtitles of some specific episodes are messed up as other episodes within the same season with PGS subtitles transcode just fine, and the reason I didn’t have any issues with other clients transcoding was because they could direct stream the PGS subtitles.

1 Like

Interesting and a good find!

I only use .srt subtitles with my Linux ISO’s and never actually heard of PGS until you mentioned them.