Some weird Playback Issues

[jonhjd 0]

Hi guys,

my users have been experiencing playback issues which I don't get.

They're experiencing playback issues like random freezing (mostly after a couple minutes of playback). This only happens with "big" movies / TV episodes, 40 Mbit/s bitrate and upwards.
This doesn't happen with smaller stuff like 2-12 Mbit/s bitrate.

My internet connection offers around 40 Mbit/s upload, in Emby I've throttled all Internet connections to 12 Mb/s - everything's being transcoded by the i5-13600's iGPU which is plenty capable of doing so.
The server itself isn't overloaded or anything.

I've attached the transcoding log as well as the Emby server log for a period of time in which a user was experiencing these freezing issues every 10 minutes or so. The playback stops indefinitely at 13:53.

I'd be grateful for any suggestions.

ffmpeg-transcode-f71a89c5-ed95-4844-ab46-50c1d59d90db_1.txt embyserver-2.txt

[visproduction 315]

ffmpeg log:
throttle=off listed 350 times

throttle=on not listed

Subtitle listed 988 times

Speed below '0.8' 3 times

data at exit:
 

Quote

video:6890537kB audio:198500kB subtitle:1kB other streams:0kB global headers:0kB muxing overhead: unknown
EXIT
 

Guesses:

Throttle service not setup correctly?

Large size of media + multiple subtitles combine to create buffering and error.  Often there are 25 subtitles in media.

 

[jonhjd 0]

2 hours ago, visproduction said:

ffmpeg log:
throttle=off listed 350 times

throttle=on not listed

Subtitle listed 988 times

Speed below '0.8' 3 times

data at exit:
 

Guesses:

Throttle service not setup correctly?

Large size of media + multiple subtitles combine to create buffering and error.  Often there are 25 subtitles in media.

 

Hm, throttling is deactivated in the Transcoding settings menu. The title that has also been experiencing playback issues has 3 subtitles.

Am I understanding something wrong or do you have any other suggestions?

[visproduction 315]

Remove the subtitles from the media that has the buffering issue and see if that helps.  Full ffmpeg command line or 3rd party tools like MKVtools can remove embedded subtitles.
see: https://www.wikihow.com/Extract-Subtitles-from-MKV

I would guess that there may be 25 subtitles embedded in the media and each one is possibly examed during the transcoding.  Any delay from doing this could cause the buffering and probably shutting down playback alltogether.  This number of subtitles works fine on Blu-ray disc playback, but is not at all optimal for streaming.  If you want a decent streaming experience remove the subtitles and copy them out to separate files.  Add these files, as needed, with the correct file name listed in the Emby guide.  Users can then pick subtitles they want, you can even force one to start with the .default.srt in the file name.  Often editing software can be set to eliminate subtitles while encoding.  Emby tries to be able to grab the subtitles, as well.  It probably runs into issues when users just leave the media untouched with 25 subtitles.  It's really one of things you should check for incoming media.

Hope that helps.

[SamES 1056]

I would also say that it's not just the speed of the network between the server and client, but also latency and any other network delays will cause playback problems.

If your network upload rate is 40Mb/s, then you will struggle to play a 40Mb/s file.  The TV will request data in bursts, not a continuous stream, so I would say 30Mb/s is probably your limit on a 40Mb/s link. Do you actually get 40Mb/s upload if you do a speed test, or is that just the maximum link speed?

[jonhjd 0]

@visproductionI'll look into this for sure. I'm probably gonna use Unmanic for this as I'm dealing with bulk media.
Thank you for your help!