Playback Error with Webm and Opus YouTube MKV

Plex Media Server
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1

I had not done this previously, but recently had a need to download a hi-res (2k) YouTube video because I needed direct access to it for reference. I first downloaded via 4K Video Downloader and it played back perfectly in VLC but Plex threw a playback error. Then I tried downloading it via youtube-dl and and still the same issue. I then downloaded it as a 1080p mp4 and it worked just fine.

I wasn’t even trying to play the file from a client, just directly from Firefox on my Mac that runs PMS. So everything is local with very fast internal drives. It has nothing to do with a speed issue, and everything to do with the video encoding.

So, I think I’ve nailed down the problem to the webm video encoding and the opus audio coming from YouTube. It’s all packaged in an MKV container but Plex refuses to play it back.

I really need it in full 2k resolution, which I cannot get by downloading the MP4.

The only solution I have come up with is to download the 2k MKV and then use FFMpeg to transcode it to an MP4 via ffmpeg -i file.mkv file.mp4. That works and Plex will play it back, but what a hassle to have to manually transcode the file.

It would be great if Plex would natively play back webm/opus MKV files so I don’t have to go through all of this if I never need to do this again.

2

Can you send me the link to the video so I can try? I can’t find any 2k webm/opus files.

FYI - That’s the Plex Web client.

3

I meant not an external client like AppleTV, just straight from the web client on the same machine that Plex is running on.

I tried it on a bunch of different YouTube videos. They apparently do not need to be 2k. Any YouTube video downloaded either via 4k Video Downloader OR youtube-dl in MKV format. MP4 format works just fine, but all MKVs no matter the resolution do not play back in Plex.

In fact, I verified this by downloading the same 720p video in both MP4 and MKV formats and the MP4 played without issue, while the MKV threw a playback error.

4

It usually happens with mkv format videos and not only on plex. I had the same problem with VLC too. This format acts weirdly sometimes on almost every app. Sometimes there is also a problem with opening videos in avi or mp4 formats. I also noticed that downloading a video from youtube can be a problem because some apps don’t support wmw format too. That’s why I need to convert videos from youtube to mp3 320kbps if it’s not necessary to see the visuals. I don’t like to waste my time on it, but it’s very useful in some cases.