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+--- Forum: General Questions (https://forum.jellyfin.org/f-general-questions)
+--- Thread: How to avoid transcoding? (/t-how-to-avoid-transcoding)
How to avoid transcoding? - WeekOk3669 - 2024-04-13
Hey!
I recently installed jellyfin on a Raspberry Pi 4 and absolutely love it!
I unfortunately have some files that contain multiple audio streams and multiple subtitle streams that I all need.
According to ffprobe all the audio streams are aac and all the subtitles are dvd_subtitle.
When I play the video, select the default audio stream and disable subs everything works great, since direct play is used.
But when I select any other audio track and/or a subtitle stream, the raspberry pi is fully occupied by trying to provide a transcoded stream for this single client.
Can I somehow prepare/extract the audio and subtitle streams so transcoding won't be necessary? I tried to extract one aac stream via ffmpeg and used it as an "external file". I was able to select it, but with external audio tracks the performance was significantly worse than just using the embedded ones and transcode.
Looking forward to suggestions and thanks for reading!
RE: How to avoid transcoding? - bitmap - 2024-04-14
Match the media to your client setup. If it's just you, that's pretty easy. Determine what client you're using (i.e., Chromecast, Roku, Jellyfin Media Player on a PC) and what it's compatible with. Most basic setups only have stereo speakers and will play UP TO 5.1 audio. Anything more than that or special codecs like DTS-MA, Atmos, etc... and you're SOL.
Additionally, subtitles don't *always* require transcoding, but anything in the "picture-based" family (DVD, VOB, PGS) generally will require transcoding on most client devices. Some ASS subs will require transcoding as well, depending on how complex they are.
So if you have a real basic setup, aim for H264 Main Profile < Level 5.1 (I think, double-check), AAC audio with 5.1 or fewer channels, make sure it's wrapped in an MP4 container, and avoid anything except SRT subtitles, preferably stored externally as an SRT file (e.g., Awesome Movie (2024).en.srt for English subs in SRT format for media called "Awesome Movie" released in 2024). Happy to elaborate, but this is the main thing folks miss -- your media has to be compatible with all of the clients you serve or your hardware has to be up to spec to handle transcoding.
Somebody will probably come in and tell you an rPi isn't recommended. I agree with that statement, but I say try with whatever you have and learn the basics of media before you invest in upgraded hardware.