Understanding Transcoding Roku

[Doobis]

Context: Running Jellyfin on an old office computer. No graphics card. I5 processor 9th gen. 

I really cant transcode anything on this machine. When it happens the image is very grainy and looks terrible or it looks "ok" but drops frames. Roku I am using is an older roku 4

I am trying to understand why some videos want to transcode and others dont. As far as my understanding the bitrate and codec are fine.

Example one Transcodes

Example two does not Transcode

Example three Transcodes

Example four does not Transcode

As far as I understand it none of these should transcode. Could someone help me understand where im going wrong?

[theguymadmax]

I5 processor 9th gen is more than sufficient to transcode. How is Jellyfin setup: OS running on, installation method: docker, exe, etc. What do you have for your transcode settings? You should have QSV enabled.

[Doobis]

OS is Debian
Not running on Docker I would of done something like the install script.
I enabled QSV today. I used to see all cores spike to the max but after enabling that the cores dont spike that high video quality is better but it drops frames.

If there are settings recommended for better trans coding ill try them but im trying to understand what im doing to cause it to transcode in the first place.

[theguymadmax]

So you probably have a UHD Graphics 630.

Make sure the below settings are enabled in your decoding and encoding settings. Also, you should enable tonemapping. 

Hardware codec support
h264ecode / Encode
AV1: No
h265 / HEVC (8 bit): Decode / Encode
h265 / HEVC (10 bit): Decode / Encode
VP8: Decode / Encode
VP9: Decode / Encode
VC-1: Decode
AVC: Decode / Encode

Transcoding audio uses your CPU, so you'll see higher CPU usage if audio also needs to be transcoded.

[Doobis]

So I tried that but when it transcodes its like it drops frames or slows down every 2 seconds. Its almost like a pulse where it just stutters. I attached screenshots of my current transcoding config. Is there something else I should change?

[ryder42]

If Jellyfin is transcoding there is some incompatibility between your media and the Roku client. Is the transcoding random or does it happen to certain media everytime? Because if it happens everytime with certain media then that is a spot for investigation. Have you checked the logs to see if Jellyfin is giving a reason for the transcoding--e.g. bitrate too high, codec not supported, etc.

The other side is the Roku client--have you checked the settings on the Roku? The Jellyfin app on there has a ton of settings that determine what codecs it will direct play and it has a maximum bitrate setting as well that could be affecting your direct play.

The handshake between the server and client can be sometimes hard to get right to direct play without transcoding. As theguymadmax is saying by figuring out adequate transcoding settings it would allow you to bypass all the incompatibility issues between your media and the Roku.

-JR

[Doobis]

It happens on certain media all the time. I agree and I’m trying to understand what about the media causes it. I tried looking in the logs in the admin portal I can’t find a reason for transcoding. As far as I can tell the codec and bitrates are supported

[ryder42]

Can you post your logs here? If you want I can take a look at them and see if I can find something as to the reason for the transcoding.

[Doobis]

I went through and read all the logs related to transcoding and the standard log. It does not give a reason why. I have one video that wont play at all on the roku but will play on a browser or on a phone using the app. My roku is 10 years old before I invest too much time trying to solve why it transcodes on that roku I decided to just buy a new one.

Since I know now my device can transcode I guess im going to try and run down why it skips frames every 2 seconds.

[spacevolvo]

I went through and read all the logs related to transcoding and the standard log. It does not give a reason why.

Perhaps MediaInfo can give you more clues:

https://mediaarea.net/en/MediaInfo