Pixelated playback when Transcoding for the first 60-90sec

Plex Media Server NAS & Devices
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Server Version#: 1.18,0.1846
Player Version#: All Versions / PS4, Chromecast, Webbrowser

Since last update each time transcoding is used there is the issue that the picture gets pixelated for the first 60-90sec. It‘s so bad that you can‘t see whats going on in the video.

After these 60-90sec the picture turns back to normal.

Only happens when transcoding and only if HW transcoding is enabled.

I transcode a 1080p file to 720p 4mbits.
System is Linux, CPU is a Intel CPU, GPU is the Intel integrated iGPU.

Will provide logs if they are needed.

1 Like
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I see the same thing on my Apple TV for HD media.

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Same her on NVIDIA shield

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We’re aware of the issue, and are investigating.

4 Likes
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If it helps…

I have Synology DS 218+, and noticed the same issue when running a hardware-aware version of ffmpeg 4 and using constant ratefactor straight from the command line. I did not have the issue when running at constant quantizer.

I think it’s a bug in ffmpeg.

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agh. I mentioned earlier that I was using an AppleTV, but that was my client of course. My server is on a QNAP TS-453bMini…

[edit: typo]

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Right, what I was trying to say is I think it’s an issue with the version of ffmpeg Plex is using (a new version of ffmpeg was recently released and I believe Plex switched to it). I’ve encoded with both Plex and a standalone version of ffmpeg on my Synology.

Plex with hardware transcoding on Synology…pixelated 60-90 seconds
ffmpg with hardware transcoding on Synology…pixelated 60-90 seconds
Plex with software transcoding on Synology…good
ffmpeg with software transcoding on Synology…good

The pixelation you are describing sounds like exactly what I’m seeing, which makes me suspect it’s not unique to QNAP or Synology. Do you know if QNAP is using VAAPI to do hardware transcoding?

1 Like
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I don’t know enough about it to know what VAAPI is. Is there a simple way for me to find out? …I will google…

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VAAPI => VA-API => Video Acceleration API?

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This support Article implies that Intel based Linux devices do use VA-API but no specific mentioning of QNAP or Synology there.

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Yes, it’s an issue with VAAPI on linux based platforms, present in both our transcoder, and upstream ffmpeg. We’re investigating, and will hopefully have some news soon.

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@DaveBinM Just out of curiosity, what version of FFMPEG are you folks based off of currently on the new transcoder.

(I know you massage the living crap out of it to fix this usecase but just wondering)

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It’s not off any particular ffmpeg version number; the tarball is linked in the LICENSE file if you want a look. :slight_smile:

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@DaveBinM Help a brother out… Umm… Where is said license file haha

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https://support.plex.tv/articles/204096476-license-information/

You should also look at PMS Install Dir/Resources/License

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Got it. 4.1.

Thanks!

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No worries!

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Hey @DaveBinM

Do we have any update regarding where this is?

Any client logs / server logs that would assist?

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We’ve identified the issue and have a fix in place. It should be out in the next beta release of Plex Media Server.

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@DaveBinM Rock on. Thanks bud.