SOLVED: Understand why a file triggered transcoding

[zbew]

Hey, first of all my setup:

- Jellyfin 10.8.9
- Fedora server
- Chromcast 3
- Pixel 7a Android latest

Yesterday I played two similar files from the same series both were WEBDL 720p on my chromecast from my android phone, and one played in direct stream mode which is okay, but the other triggered transcoding which don't work well on my low-end server.

Could someone explain me from logs files why one triggered transcoding and how to avoid this in the future ?

Since i could not find any spoiler tag i put logs as attached files to avoid too big post.


  directstream_logs.txt (Size: 80 KB / Downloads: 60)
  transcoding_logs.txt (Size: 42.44 KB / Downloads: 73)

Thanks in advance for your help

[crobibero]

It’s difficult to see why something transcoded from the ffmpeg log, but you should be able to see it in the Jellyfin log by looking for TranscodeReason

[TheDreadPirate]

If I had to guess, its because the one that transcoded had 10-bit color.

Stream #0:0: Video: hevc (Main 10), yuv420p10le(tv, bt709), 1280x720 [SAR 1:1 DAR 16:9], 24 fps, 24 tbr, 1k tbn (default)

[zbew]

It’s difficult to see why something transcoded from the ffmpeg log, but you should be able to see it in the Jellyfin log by looking for TranscodeReason

Oh ty, i had no idea those were separate logs from ffmep, it appears the reason is VideoCodecNotSupported

If I had to guess, its because the one that transcoded had 10-bit color.

Stream #0:0: Video: hevc (Main 10), yuv420p10le(tv, bt709), 1280x720 [SAR 1:1 DAR 16:9], 24 fps, 24 tbr, 1k tbn (default)

Tbh honnest i don't know a lot about video file expect format and resolution, I bet this has to do with to codec mentioned by jellyfin logs.

So I guess my best bet is to use a software to automatically transcode into a chromecast supported codec after download and before adding to the library ?

[TheDreadPirate]

So I guess my best bet is to use a software to automatically transcode into a chromecast supported codec after download and before adding to the library ?

The CODEC is supported by your chromecast, but the color depth is not.  It supports 8-bit color but not 10-bit color.  The file name did not include any specifics about color depth so that can't be relied on.

There are tools to re-encode videos.  Handbrake is one.  I think tdarr can semi-automate this.

[zbew]

Got it thanks both of you for the help, i'll try to setup tdarr accordingly.