SOLVED: Format compatibility questions

[podonnell]

I ran into two new compatibility issues this week, can't exactly remember which device, but the errors were:

1) The media is in an incompatible file container (MKV)

2)The video stream is compatible with the device but has an incompatible audio format -- or number of audio channels.


For #1 --> Are certain file containers compatible globally? Such as, will MKV always be a problem? Or is that dependant on the device its streaming to?
I don't recall seeing issues with the stream when this happened, but I'd love to avoid this altogether if I can. Just want to know what format I should ideally have my video files in.

For #2 --> I think this case was number of audio channels, as I've had an audio format error before that called out exactly which format -- TrueHD for example.
In this case, if I was sending over a video that had a 5.1 Dolby Digital audio, and my device was only 2 speakers, that would cause a transcode? I know Jellyfin has an option to convert any files that are more than 2 channels down to stereo, and I believe I have that on most devices.
This, again, didn't appear to be problematic when it was converted. But I'd like to prevent a transcode where possible. If I do have a device that supports 5.1 and another device that doesn't, I'm guessing I don't really have any options?

[TheDreadPirate]

If you MUST avoid transcoding, or even remuxing (#1), you should have H264 video, AAC stereo audio, SRT or burned in subs, in a MP4 container.

Or you could allow transcoding if your hardware supports it. Allowing remuxing (changing containers without re-encoding) uses almost not CPU power.

What are your hardware specs?

[theguymadmax]

It varies depending on what client you are using. Check out this guide, as you can see there are many variables.

[podonnell]

If you MUST avoid transcoding, or even remuxing (#1), you should have H264 video, AAC stereo audio, SRT or burned in subs, in a MP4 container.

Or you could allow transcoding if your hardware supports it.  Allowing remuxing (changing containers without re-encoding) uses almost not CPU power.

What are your hardware specs?

Working on an upgrade, I'm the guy with the 4790k using VAAPI.
I had the issue where a TrueHD codec was causing me a dropped frame every 6 seconds or so. Tried another video with TrueHD and it didn't happen as often. I'm just getting some oddities whenever there's a transcode required, even one that's just a container / audio format one.

I think the remuxing was working fine, just much prefer to get a direct play when I can. I think I have a lot of MKV files, those will always cause a transcode? Might not be a problem like the audio ones were.

[TheDreadPirate]

Remuxing alone is, practically speaking, direct playing since nothing is being re-encoded. But if something is bottlenecking your system, whether that is disk throughput, maybe it would cause that stuttering/dropped frame issue. Is the directory transcodes written to a SSD or HDD?

MKVs on their own will only cause re-muxing. What codecs are in the MKVs will determine whether transcoding happens. Audio channels I don't think cause transcoding. Most clients will just downmix the channels to whatever is available. I believe web browsers will require audio transcodes for 7.1 since they support 5.1 max.

[podonnell]

Remuxing alone is, practically speaking, direct playing since nothing is being re-encoded.  But if something is bottlenecking your system, whether that is disk throughput, maybe it would cause that stuttering/dropped frame issue.  Is the directory transcodes written to a SSD or HDD?

MKVs on their own will only cause re-muxing.  What codecs are in the MKVs will determine whether transcoding happens.  Audio channels I don't think cause transcoding.  Most clients will just downmix the channels to whatever is available.  I believe web browsers will require audio transcodes for 7.1 since they support 5.1 max.

Appreciate that info. I will keep an eye on the error and see if I do get frame drops. I do have the transcodes writing to an SSD, but I do see the drive get to 100% utilization when it happens. Not sure if I can do more to help with that or not.