Mysterious 1 kbps bitrate for AAC encoded files [Ticket In]

Hi,
I found Roon reporting only “1 kbps” for some of my AAC encoded files where all my other “metadata tools” will report the correct bitrate of 242 kbps (see screenshots).
How does Roon calculate “1 kbps”?
BTW: The bit depth is different too (16 vs. 24 as reported by Roon)…

Roon-AAC
Roon-AAC-Signal-Path
Roon-AAC-AudioProperties
Roon-AAC-vs-OpenTag%26renameTool

Recent Roon versions have displayed the 24 bit decoded bit depth for lossy audio files, which no longer have an inherent bit depth and can be decoded to any arbitrary bit depth. The bit depth that you point out in the file info was the input bit depth prior to lossy audio encoding.

AJ

I understand the bit depth issue but I wonder why Roon displays “256 kbps” or “320 kbps” for the majority of my AAC files. I cannot see any difference and I have no idea WHEN “1 kpbs” resp. “256” kpbs" will be presented to me…

An observation: are some of your files variable bit rate (VBR)? 256kbps and 320kbps are continuous bit rates (CBR) whereas 242kbps is not. Roon is converting the lossy file to PCM.

You are right.
All of the files with “1 kbps” presented by Roon are encoded with VBR AAC. That seems to make up the difference.
Anyway, I had expected something like “~250 kbps” in which the “~” sign would signal that Roon cannot present only one value for the bitrate tag…
…whereas “1 kbps” tells me that the file is encoded really very lossy, i.e, very bad :sweat_smile:

Hello @KPB,

Could you upload one of the media files being identified as 1 kbps to a sharing service like dropbox and then PM me a link? I’m going to have the QA team take a look at this.

-John

Hi, did this get resolved? I’ve got the same issues, i.e. anything I convert with dbpoweramp to VBR AAC is being shown with a bitrate of 1 kpbs while all other audio players I’ve checked correctly determine the bitrate at ~224 kbps

Hi @SSt,

Can you please upload a sample media file of this behavior to Dropbox / Google Drive and send us a link?

Here’s an example file converted via dbpoweramp to VBR AAC:

“!https://www.dropbox.com/s/2vh0k9ov017kjmw/01%20-%20Einleitung.m4a?dl=0

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Hi @noris,
here is a dropbox link from my side too:
https://www.dropbox.com/s/bohqpt3s9vinml8/08%20-%20Woman%20From%20Tokyo.m4a?dl=0
It is a VBR AAC encoded file with ~217 kbps, shown as “1 kbps” inside Roon…

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Thanks for sending these files over @KPB & @SSt, let me get them over to QA for closer inspection!

Hey @KPB/@SSt,

I wanted to touch base with some good news, which is that our technical team has been able to reproduce this behavior and we’ve opened up a bug report with our developers.

While I can’t say for certain when this bug will be fixed, getting things reproduced in-house is a critical first step, and I will keep this thread up to date as the team passes along feedback and work begins to get this resolved. Thanks again for the report!

Hi @noris,

thanks, much appreciated.

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