Hi folks, I’d appreciate some help with troubleshooting a buffering problem.
Plex keeps buffering video even though it’s played on localhost web player.
Video file is ~10GB. I first tried streaming it to my Chromecast (3rd gen) but was constantly buffering. Then tried watching it directly on my plex media server windows PC, through the web player - same story - constantly buffering.
I lowered the quality from automatic (16mbps) to as low as 1080p HD (10mbps) but still have same buffering issues (no change at all).
Plex Server version: 1.19.1.2645
Windows 10 kb4549951
Intel Nuc Mini Complete PC - Intel Quad Core 4x2.30GHz, 8 GB RAM.
Plex is installed on 256gb ssd, Data is on external HDD directly connected to the media server.
Using the browser for video playback to troubleshoot buffering issues is not necessarily a good choice. Browser based players (including Plex Web) have a very limited support for different video types and codecs. That’s why Plex will instead try to transcode your video.
You should also be able to see this by opening Plex Activities / Now Playing section in a parallel Plex Web session (tab/window). It’ll probably show that both video and audio are being transcoded for that particular stream.
When it comes to transcoding, the playback performance highly depends on your server’s capabilities… mostly CPU power (unless you’re a Plex Pass member who can use hw accelerated streaming… in which case it comes still down to the hardware capabilities but won’t consume all of your CPU power).
I’m not 100% sure about what exact NUC model you’re using. Could you provide the exact processor? -> right click the Windows icon / start menu, click System and look for the Processor information.
It appears the NUC simply hasn’t enough power to do the necessary transcodes. That’ll also explain why you get the same behavior by reducing the quality (which is also causing the video to be transcoded).
When the client says that it is not connected directly to the server (but the server is in the same local network), it usually means you have either a general issue with DNS or with “DNS rebinding protection” specifically.
First step: try using the hosted web app in a fresh web browser session: https://app.plex.tv
Disable any web browser add-ins you might have activated. If that clears the error, re-enable them one by one and repeate the playback test until you have found the culprit.
Second step:
configure your router or your computer to use the DNS servers of Google: 8.8.8.8 and/or 8.8.4.4
You are right, it says that it’s transcoding.
I still don’t understand though… Under what circumstances does the server decide that it’s time to transcode or stream as-is?
Is it the movie size that is causing it to transcode? I have never had any problems with other movies/tv shows up until now - but this one is quite large - 10GB for 2 hours movie is a little bit above what I usually watch.
Also, how come when I stream movies to my Android or Chomecast device, the Activity dashboard on the Plex Media Server doesn’t show anything? I always thought that Server is transcoding everytime I cast to the Chromecast… is this not the case? How can I confirm that?
Well actually, as you can see on the screenshot - the web browser URL is 127.0.0.1:32400, which basically means it’s not even going through the network or using any DNS - it’s all local to the Plex Media Server.
The reason for transcoding can be due to a ton of things…
The short of it is that the player doesn’t support something about the media characteristics of your source material.
In the case of your video being played in the browser, Plex struggled with 2 elements:
the browser doesn’t support playback of HEVC HDR video – therefore Plex is transcoding the video to h264.
the browser doesn’t support EAC audio, nor 5.1 channels – therefore it’s transcoding the audio to AAC and 2 channels (stereo).
As your CPU isn’t super powerful, it ends up transcoding to 720p (resolution) and h264 (video codec).
As for the CPU…
software/CPU based transcoding to a 1080p h264 video to an average quality bitrate requires a CPU with a PassMark score of approx. 4000 (PassMark is a benchmark that tries to rate the performance of CPUs)
software/CPU based transcoding to a 720p h264 video requires a PassMark score of approx. 1500.
your CPU has a PassMark of approx. 2500… so it’ll deal fine with encoding a video to 720p but won’t be able to deal with 1080p or 4K content (unless the player is able to play it as-is).
Different players have different capabilities.
When it comes to general compatibility… your best shot is to go with:
h264 video (level 3 or 4)
AAC or AC3 audio
text based subtitles
If you cast the video through Chromecast from Plex it should show on your now playing dashboard – unless you’re streaming from a different server / not using Plex… This has nothing to do with the server having to transcode the video or playing it directly.
