Audio transcode fail??

[lightsout 156]

Can anyone help me understand what's happening here. I am using the app Symphomnium, when I try to download offline files with a max bitrate I get a http 500 error, the dev said all he sees in the logs are the error and to come ask here.

If I turn off the max bitrate and leave the quality at original the issue goes away. Attaching a log. I can pm someone the embyserver log.

ffmpeg-transcode-e5cc5556-7bd7-4713-b265-a3ba7dd98dcc_1.txt

[rbjtech 5284]

Not sure why you would want to convert mp3 to opus - but this is the error in the logs -

Looks like a possible bug in the max bitrate being passed in the ffmpeg command

-c:a:0 libopus -ab:a:0 262144

It then goes on to suggest the max bitrate is 256000

06:30:18.795 [libopus @ 000001964ce735c0] The bit rate 262144 bps is unsupported. Please choose a value between 500 and 256000.

I presume when you keep original quality (which will be the best quality anyway) it does not convert - and does a straight copy of the mp3 ...

 

[lightsout 156]

29 minutes ago, rbjtech said:

Not sure why you would want to convert mp3 to opus - but this is the error in the logs -

Looks like a possible bug in the max bitrate being passed in the ffmpeg command

-c:a:0 libopus -ab:a:0 262144

It then goes on to suggest the max bitrate is 256000

06:30:18.795 [libopus @ 000001964ce735c0] The bit rate 262144 bps is unsupported. Please choose a value between 500 and 256000.

I presume when you keep original quality (which will be the best quality anyway) it does not convert - and does a straight copy of the mp3 ...

 

I don't necessarily want to transcode mp3 to opus. I guess that is what the app (or emby) is set to do. I prefer mp3 to download as it is, which it does well. I had originally turned that setting on when listening to FLAC, as some of it was 1mbps and up, and I didn't want my phone storage filling up too quick.

Sounds like the app is sending an odd bitrate amount?

[Luke 42079]

The app is requesting a conversion to opus, which I understand why you'd want to do that, but given that Emby apps don't currently do that, we have not been putting any testing time into this. So it's something we'll have to look into. Immediate workaround would be to configure the app request mp3 instead.

[Tolriq 141]

The app does not ask to transcode mp3 to Opus, it just send a profile with a max bitrate if the user configure it and let Emby decide if it transcode or not for that bitrate. So MP3 with bitrate <= at the requested max bitrate should not transcode.

For the Opus I think it was working before correctly and either Emby did clip the value or did select the next transcoding profile automatically if the first one is not compatible with the request. (So that would fallback to mp3 automatically).

I can add a maxbitrate condition to opus in the profile, to workaround on my side but yes would be better if Emby did that automatically, most things works in Kibi and 262144 is 256Kbps for most

[Tolriq 141]

Ok so no it's actually a special case and opus codec still works correctly in Emby with such bitrate, this is about the opus container that is limited to 256000.

I normally request ogg container but seems for downloads with transcoding I made a typo and it was choosing opus container causing this issue.

I don't think this worth much investigation on Emby side, Opus container have no reason to be used over ogg for this use case.