Enabling Transcoding trancodes otherwise working files

[DreamVoice]

Jellyfin version: 10.10.6
Windows Installer (Win10, RTX 3080)

Device issue occurs on: Roku Express 4k connected to a 1080p Sony Bravia (HDMI) (Roku Jellyfin app has been updated to latest)

Problem/Issue: Enabling video transcoding results in video transcodes for files that played just fine without video transcoding (but previously required audio transcode only).

I recently enabled transcoding on my server due to a new video requiring video transcoding. This seems to have added the side-effect of some other videos also experiencing video transcoding when previously they only required audio transcoding (Direct Stream) without video transcoding (ie they play with "Allow video playback that requires transcoding" disabled).

I've included two logs. The first showing the play of the same file with "Allow video playback that requires transcoding" in the user Media Playback settings disabled ("Direct Stream" log showing the video plays just fine on the Roku device without video transcoding).

The second log showing the play of the same file with "Allow video playback that requires transcoding" enabled ("Transcoding" log showing that for some reason it transcodes the video even though it doesn't require it).

This is all local network play.

Are there any settings that can fix this behaviour? I have no idea why the file plays without video transcoding but then transcodes it anyway if video transcoding is enabled.

[TheDreadPirate]

I'm not at home to double check, but I recall that in the Roku app there is a setting to direct play MPEG2.

With transcoding disabled on the server, it may "force" that setting on.

[DreamVoice]

I'm not at home to double check, but I recall that in the Roku app there is a setting to direct play MPEG2.

With transcoding disabled on the server, it may "force" that setting on.

It seems on the Roku app under "codecs" there is a setting to enable/disable direct play MPEG2. I tried both settings but still end up with the same result: video plays fine with transcoding disabled, but Jellyfin decides to transcode video if transcoding is enabled. 

Is it possible there's some sort of issue with Jellyfin failing to discover that the Roku can play MPEG2 without transcoding when transcoding is enabled?

[TheDreadPirate]

I remembered a github ticket I submitted a few months ago.

https://github.com/jellyfin/jellyfin-roku/issues/2024

IIRC, a dev said it was some sort of race condition that is causing this. And I think this is the same issue you are experiencing, but in reverse for you and in MKV containers instead of TS.

[DreamVoice]

I remembered a github ticket I submitted a few months ago.

https://github.com/jellyfin/jellyfin-roku/issues/2024

IIRC, a dev said it was some sort of race condition that is causing this.  And I think this is the same issue you are experiencing, but in reverse for you and in MKV containers instead of TS.

I just read through that ticket and it indeed seems to be the reverse of my issue. I wonder if that ticket issue was fixed and the fix mistakenly made the issue flow in the opposite direction, so to speak.  Is there any more info or logs I can give to help narrow it down further, im not to adept at troubleshooting, I'm afraid.

[TheDreadPirate]

AFAIK, there has been no fixed implemented. The ticket would have been updated with a PR#. Race conditions are difficult to reproduce and test since two devices won't behave exactly the same. Or even have the problem described at all.