Transcoding issues

General Discussions
1

Server version:

1.14.1.5488

OS:

Virtual Machine (KVM virtualization) CentOS 7.6.1810

Clients, w/ versions, if applicable:

Firefox/Chrome/Samsung TV (different behavior between Samsung TV and browsers it seems)

What you did?

  • I’ve set up a standard CentOS with Plex, CentOS OS and CentOS Updates repositories configured.
  • Installed Plex and didn’t change anything notably.
  • Installed Cigaras/IPTV.bundle.
  • Added a simple m3u file with a stream.
  • Opening the IPTV plugin, select the stream.

What happened?

  • On TV: opens stream correctly without issues
  • On Firefox/Chrome browser: stream fails to start I see the CPU load going up, files being created for Transcoding and after a short amount of time these files dissapear again. In the browser I just see the loading wheel with a “cloudy” background. When I stop I get an error about failed transcoding.
  • In the browser console I see that the browser is reaching out to the video stream (so URL where the stream is hosted outside my network) using a HEAD call (I thought the server would connect to the source, transcode it and send it from the plex server to the browser, can someone explain this behavior?). I can use this URL in e.g. VLC and it plays the stream). This HEAD request doesn’t get any response (this might be irrelevant to the issue but I still wonder why this is happening).
  • I see 404 errors in the browser console trying to retrieve 1.m4s files.
  • I see 200% (multiple cores full load) CPU load on the system and the transcoder process running. Then after some seconds it crashes.
  • Video files in the library are playing correctly everywhere, all the time.

What you expected? See the stream in the browser.

I’d like to understand what’s different for my browser than for the TV (where it’s working). Earlier I had Plex installed on a Windows laptop and there I could open the stream without an issue in the browser. I’ve tested on 2 different laptops with the same issue.

What are your (relevant) settings? I can’t think of any special settings I’ve done. Mostly turning of crash reporting, … (although I still see statistics calls going outside?)

Link to logs (optional but recommended):

I see a lot of the messages below in the logs. What I wonder is if this is incorrect detection of the encoding type. I believe VLC reported the source as AC3 while the logs show aac?

Plex Media Server.log:Dec 27, 2018 22:59:53.735 [0x7f8efbfff700] ERROR - [Transcoder] [aac @ 0x18bddc0] Dependent coupling is not supported together with LTP
Plex Media Server.log:Dec 27, 2018 22:59:53.736 [0x7f8ee57fd700] ERROR - [Transcoder] [aac @ 0x18bddc0] Dependent coupling is not supported together with LTP
Plex Media Server.log:Dec 27, 2018 22:59:53.737 [0x7f8efbfff700] ERROR - [Transcoder] [aac @ 0x18bddc0] Dependent coupling is not supported together with LTP
Plex Media Server.log:Dec 27, 2018 22:59:53.737 [0x7f8ee57fd700] ERROR - [Transcoder] [aac @ 0x18bddc0] Dependent coupling is not supported together with LTP
Plex Media Server.log:Dec 27, 2018 22:59:53.738 [0x7f8efbfff700] ERROR - [Transcoder] [aac @ 0x18bddc0] Dependent coupling is not supported together with LTP
Plex Media Server.log:Dec 27, 2018 22:59:53.738 [0x7f8ee57fd700] ERROR - [Transcoder] [aac @ 0x18bddc0] Dependent coupling is not supported together with LTP
Plex Media Server.log:Dec 27, 2018 22:59:53.739 [0x7f8efbfff700] ERROR - [Transcoder] [aac @ 0x18bddc0] Dependent coupling is not supported together with LTP
Plex Media Server.log:Dec 27, 2018 22:59:53.739 [0x7f8ee57fd700] ERROR - [Transcoder] [aac @ 0x18bddc0] Dependent coupling is not supported together with LTP
Plex Media Server.log:Dec 27, 2018 22:59:53.740 [0x7f8efbfff700] ERROR - [Transcoder] [aac @ 0x18bddc0] Dependent coupling is not supported together with LTP
Plex Media Server.log:Dec 27, 2018 22:59:53.740 [0x7f8ee57fd700] ERROR - [Transcoder] [aac @ 0x18bddc0] Dependent coupling is not supported together with LTP
Plex Media Server.log:Dec 27, 2018 22:59:53.741 [0x7f8efbfff700] ERROR - [Transcoder] [aac @ 0x18bddc0] Dependent coupling is not supported together with LTP
Plex Media Server.log:Dec 27, 2018 22:59:53.741 [0x7f8ee57fd700] ERROR - [Transcoder] [aac @ 0x18bddc0] Dependent coupling is not supported together with LTP
Plex Media Server.log:Dec 27, 2018 22:59:53.742 [0x7f8efbfff700] ERROR - [Transcoder] [aac @ 0x18bddc0] Dependent coupling is not supported together with LTP
Plex Media Server.log:Dec 27, 2018 22:59:53.742 [0x7f8ee57fd700] ERROR - [Transcoder] [aac @ 0x18bddc0] Dependent coupling is not supported together with LTP
Plex Media Server.log:Dec 27, 2018 22:59:53.743 [0x7f8efbfff700] ERROR - [Transcoder] [aac @ 0x18bddc0] Dependent coupling is not supported together with LTP
Plex Media Server.log:Dec 27, 2018 22:59:53.743 [0x7f8ee57fd700] ERROR - [Transcoder] [aac @ 0x18bddc0] Dependent coupling is not supported together with LTP
Plex Media Server.log:Dec 27, 2018 22:59:53.744 [0x7f8efbfff700] ERROR - [Transcoder] [aac @ 0x18bddc0] Dependent coupling is not supported together with LTP
Plex Media Server.log:Dec 27, 2018 22:59:53.744 [0x7f8ee57fd700] ERROR - [Transcoder] [aac @ 0x18bddc0] Dependent coupling is not supported together with LTP
Plex Media Server.log:Dec 27, 2018 22:59:53.745 [0x7f8efbfff700] ERROR - [Transcoder] [aac @ 0x18bddc0] channel element 3.0 is not allocated
Plex Media Server.log:Dec 27, 2018 22:59:53.745 [0x7f8ee57fd700] ERROR - [Transcoder] Error while decoding stream #0:1: Invalid data found when processing input
Plex Media Server.log:Dec 27, 2018 22:59:53.746 [0x7f8efbfff700] ERROR - [Transcoder] [aac @ 0x18bddc0] Number of bands (14) exceeds limit (5).
Plex Media Server.log:Dec 27, 2018 22:59:53.746 [0x7f8ee57fd700] ERROR - [Transcoder] Error while decoding stream #0:1: Invalid data found when processing input
Plex Media Server.log:Dec 27, 2018 22:59:53.775 [0x7f8ee97fe700] ERROR - [Transcoder] [aac @ 0x18bddc0] channel element 1.14 is not allocated
Plex Media Server.log:Dec 27, 2018 22:59:53.776 [0x7f8ee57fd700] ERROR - [Transcoder] Error while decoding stream #0:1: Invalid data found when processing input
Plex Media Server.log:Dec 27, 2018 22:59:53.806 [0x7f8ee97fe700] ERROR - [Transcoder] [aac @ 0x18bddc0] Number of scalefactor bands in group (48) exceeds limit (40).
Plex Media Server.log:Dec 27, 2018 22:59:53.807 [0x7f8ee57fd700] ERROR - [Transcoder] Error while decoding stream #0:1: Invalid data found when processing input
Plex Media Server.log:Dec 27, 2018 22:59:53.817 [0x7f8ee97fe700] ERROR - [Transcoder] [aac @ 0x18bddc0] Inconsistent channel configuration.
Plex Media Server.log:Dec 27, 2018 22:59:53.818 [0x7f8ee57fd700] ERROR - [Transcoder] [aac @ 0x18bddc0] get_buffer() failed
Plex Media Server.log:Dec 27, 2018 22:59:53.818 [0x7f8ee97fe700] ERROR - [Transcoder] Error while decoding stream #0:1: Invalid argument
Plex Media Server.log:Dec 27, 2018 22:59:53.866 [0x7f8ee97fe700] ERROR - [Transcoder] [aac @ 0x18bddc0] Number of bands (13) exceeds limit (10).
Plex Media Server.log:Dec 27, 2018 22:59:53.867 [0x7f8ee57fd700] ERROR - [Transcoder] Error while decoding stream #0:1: Invalid data found when processing input
Plex Media Server.log:Dec 27, 2018 22:59:54.363 [0x7f8efbfff700] ERROR - [Transcoder] [aac @ 0x18bddc0] channel element 1.6 is not allocated
Plex Media Server.log:Dec 27, 2018 22:59:54.364 [0x7f8ee97fe700] ERROR - [Transcoder] Error while decoding stream #0:1: Invalid data found when processing input
Plex Media Server.log:Dec 27, 2018 22:59:54.373 [0x7f8efbfff700] ERROR - [Transcoder] [aac @ 0x18bddc0] channel element 2.4 is not allocated
Plex Media Server.log:Dec 27, 2018 22:59:54.382 [0x7f8ee97fe700] ERROR - [Transcoder] Error while decoding stream #0:1: Invalid data found when processing input
Plex Media Server.log:Dec 27, 2018 22:59:54.441 [0x7f8efbfff700] ERROR - [Transcoder] [aac @ 0x18bddc0] Reserved bit set.
Plex Media Server.log:Dec 27, 2018 22:59:54.443 [0x7f8ee97fe700] ERROR - [Transcoder] [aac @ 0x18bddc0] Number of bands (29) exceeds limit (10).
Plex Media Server.log:Dec 27, 2018 22:59:54.446 [0x7f8efbfff700] ERROR - [Transcoder] Error while decoding stream #0:1: Invalid data found when processing input
Plex Media Server.log:Dec 27, 2018 22:59:54.480 [0x7f8ee57fd700] ERROR - [Transcoder] Error while decoding stream #0:1: Not yet implemented in FFmpeg, patches welcome
Plex Media Server.log:Dec 27, 2018 22:59:54.598 [0x7f8ee97fe700] ERROR - [Transcoder] [aac @ 0x18bddc0] Inconsistent channel configuration.
Plex Media Server.log:Dec 27, 2018 22:59:54.599 [0x7f8ee57fd700] ERROR - [Transcoder] [aac @ 0x18bddc0] get_buffer() failed
Plex Media Server.log:Dec 27, 2018 22:59:54.599 [0x7f8ee97fe700] ERROR - [Transcoder] Error while decoding stream #0:1: Invalid argument
Plex Media Server.log:Dec 27, 2018 22:59:54.600 [0x7f8ee57fd700] ERROR - [Transcoder] [aac @ 0x18bddc0] channel element 2.10 is not allocated
Plex Media Server.log:Dec 27, 2018 22:59:54.601 [0x7f8ee97fe700] ERROR - [Transcoder] Error while decoding stream #0:1: Invalid data found when processing input
Plex Media Server.log:Dec 27, 2018 22:59:54.605 [0x7f8efbfff700] ERROR - [Transcoder] [aac @ 0x18bddc0] Inconsistent channel configuration.
Plex Media Server.log:Dec 27, 2018 22:59:54.605 [0x7f8ee57fd700] ERROR - [Transcoder] [aac @ 0x18bddc0] get_buffer() failed
Plex Media Server.log:Dec 27, 2018 22:59:54.606 [0x7f8efbfff700] ERROR - [Transcoder] Error while decoding stream #0:1: Invalid argument
Plex Media Server.log:Dec 27, 2018 22:59:54.618 [0x7f8ee97fe700] ERROR - [Transcoder] [aac @ 0x18bddc0] Reserved bit set.
Plex Media Server.log:Dec 27, 2018 22:59:54.620 [0x7f8efbfff700] ERROR - [Transcoder] [aac @ 0x18bddc0] Sample rate 0 invalid
Plex Media Server.log:Dec 27, 2018 22:59:54.622 [0x7f8ee57fd700] ERROR - [Transcoder] Error while processing the decoded data for stream #0:1
Plex Media Server.log:Dec 27, 2018 22:59:54.709 [0x7f8ee27fe700] DEBUG - Streaming Resource: Terminated session 0x7f8efec1e520:towqb8s7bctbjcwx7by7nlp9 with reason Conversion failed. The transcoder exited due to an error.

Retries

I have literally left everything unchanged. However half a day later the stream was playing in the browser without an issue. I see no CPU load in the statistics this time though.
Now this evening it’s again spewing these errors and not showing the stream.

There does seem to be a transcoding process running though.

/usr/lib/plexmediaserver/Plex Transcoder -codec:V:0 h264 -noaccurate_seek -probesize 10000000 -i http://videostreamsource:1234/xxxxxxx/abcdefg/1111 -map 0:V:0 -codec:0 copy -map 0:a:0 -codec:1 copy -copypriorss:1 0 -f dash -min_seg_duration 5000000 -skip_to_segment 1 -time_delta 0.0625 -manifest_name http://127.0.0.1:32400/video/:/transcode/session/f5a7d76jcnmseegagh44rw4s/12944e15-002c-4fd9-a58e-e92cbd374a24/manifest -avoid_negative_ts disabled -map_metadata -1 -map_chapters -1 dash -start_at_zero -copyts -vsync cfr -y -nostats -loglevel quiet -loglevel_plex error -progressurl http://127.0.0.1:32400/video/:/transcode/session/f5a7d76jcnmseegagh44rw4s/12944e15-002c-4fd9-a58e-e92cbd374a24/progress

** Other questions**

I would like to better understand Plex and how it handles streams.

  • Is there some kind of flow chart or brief description on what Plex is doing in the background?
  • Will a samsung smart tv handle streams differently which explains why it always worked there but not in the browser?
  • Why is the video player in the browser doing a HEAD request on the actual source stream? Shouldn’t it pass through Plex and not expose anything to the browser (or perhaps this is the setting Direct Stream Video Stream I’ve seen somewhere in the interface)?
  • Is it ok to run Plex virtualized or are issues expected in this setup(although everything seems to be working smoothly right now)?
  • Can audio transcoding errors result in the stream not working alltogether? or would it just result in a loss of audio but still have video?
  • Why do I see these errors for the browsers and is the TV working just fine?

I’ve seen other cases where I transcoding seems to keep on running and new segments are retrieved yet I don’t see anything except a black screen with the loading wheel. When opening the same stream on another system (also with Firefox) it’s working. Using Chrome instead doesn’t result in the stream working either.

Thanks a lot in advance!

2

Anyone here?

3

Still nobody who knows something about plex on the plex forum?

4

plugins are deprecated, and plex doesn’t support ip tv streaming, so its likely that plugin doesn’t work and not likely to get fixed.

as far as how plex works, basically it is a client / server system

  • the server indexes your media and downloads/stores metadata for your content, creates a database and library which you can use to view your content
  • the clients (there are many different kinds) connect to the plex server and stream via https streams generated at the server.
  • the server will attempt to automatically transcode your content to fit both your internet bandwidth limits (client and server limits) and codec incompatibilities.
  • in cases where your client and content can direct play, the server essentially divides it up into smaller chunks which are sent over https from the server to the client (which reassembles/plays the resulting stream).

this is my understanding of the overall process (may not be completely accurate)

regarding other questions I’ll try to answer

  1. see above
  2. yes, different clients have different compatibility with different codecs (both video and audio)
  3. no idea probably part of the way the plugin was designed, which as mentioned is deprecated and no longer supported
  4. many people run virtualized with various levels of success and performance. obviously bare metal provides the most supported, best and most consistent performance.
  5. I can’t say for sure but I would imagine that yes, any transcoder errors can stop the stream
  6. a wild guess would be probably whether or not the the stream is mpeg2 and that the tv can direct play that codec while the web browers would be converted (and failing) to x264
5

First of all thanks for taking your time to reply to this thread.

plugins are deprecated, and plex doesn’t support ip tv streaming, so its likely that plugin doesn’t work and not likely to get fixed.

This is kind of weird. The live content that Plex shows is actually TV over IP. So I doubt/am sure the plugin is not the culprit.
The only thing that plugin does is load an m3u playlist and afaik tell Plex to process stream X. Plex does the actual playing of the stream.
I’m surprised with the path that Plex seems to be walking by deprecating plugins.

Thanks for explaining the overall process and your answers.

6

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