Build 334: AAC 24bit conversion - audio artefacts [Resolved B339]

I get it on both.

I also have this problem when play local AAC music file (24 bit 44.1Hz) bought from apple iTunes . Now all iTunes music AAC will have clipping sound .

More information . I run roon core server on QNAP TS-453-A with the latest firmware(4.3.4.0644). ROON server version 1.5 (build 334 ) . I run ROON on QNAP and ROON audio device is set to DCS Rossini . If i use DCS original playback APP, there is no clipping sound problem on AAC local file (bought from iTunes ) But if i use ROON server as playback APP . This clipping sound problem will be occurred (100% on AAC local file )

This clipping sound still occur even i turn off 24 bit conversion .

Please help

Sorry for the trouble here @Chi_Chung_Fung – see my post here, we are working on a fix:

I could provide a temporary (interim-) qpkg for qts 4.3.x which has ffmpeg 4 included. If you‘d like to try it send me a PM.

When the fix for RoonServer is ready, you can revert back to the current QNAP Appstore version.

I’m confused about how often we should update ffmpeg and from where.

Hi @fritzg ---- Thank you for the question! I wanted to reach out and offer some clarification here.

You shouldn’t need to update ever, this is just a bug in our last release which we are working to fix asap.

-Eric

I also have the clipping problem. Looks like all AAC files are having this issue, not only Tidal but also local files. I use a NUC i7 with Roon 1.5 (build 334). Is there also a temp ffmpeg solution for my NUC?

Clipping problem is now fixed, i asked my son to install the update for FFMPEG on the NUC with Ubuntu.

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I also have the same problem. I use the docker install of roonserver using debian 9 and that version of ffmpeg also seems to be affected.

see: https://github.com/steefdebruijn/docker-roonserver/blob/master/Dockerfile

I’m looking for a way to update the Dockerfile

Intersample overs?

Sounds like the ubiquitous problem of inter-sample overs. Since digital signals greater than 0 dbfs are not defined the result is highly equipment as well as software conversion methodology dependent.

Inter-sample overs are ubiquitous in rock pop. They occur on CD as well as other downloadable digital files.

https://benchmarkmedia.com/blogs/application_notes/intersample-overs-in-cd-recordings

Only an interpolator with extra headroom can cope.

Quote

“Every D/A chip and SRC chip that we have tested here at Benchmark has an intersample clipping problem! To the best of our knowledge, no chip manufacturer has adequately addressed this problem. For this reason, virtually every audio device on the market has an intersample overload problem. This problem is most noticeable when playing 44.1 kHz sample rates.”

Of course the problem will be even worse at 22.05 KHz.

The dockerfile installs ffmpeg from Debian’s repositories, which are very conservative. I just installed the static ffmpeg version that is also used in ROCK installs. Goes for regular Linux installations as well.

Open a bash into the container:

docker exec -i -t containername bash

Remove the old ffmpeg:

apt remove ffmpeg

Download the static version:

curl -O https://johnvansickle.com/ffmpeg/releases/ffmpeg-release-64bit-static.tar.xz

Untar the archive:

tar -xJf ffmpeg-release-64bit-static.tar.xz

Enter the ffmpeg dir:

cd ffmpeg-4.0.2-64bit-static

Copy the ffmpeg static file:

cp ffmpeg /usr/bin/ffmpeg

Set to executable:

chmod +x /usr/bin/ffmpeg

Clean up the downloaded/unarchived files and done! :slight_smile:

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I’m having what sounds like the same issue discussed here on a local AAC file (I don’t use Tidal).

I started this thread,

And was pointed here.

Is there something I need to do, or just wait for a fix from Roon? Some of the posts here sound like the Roon team is aware of this issue?

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Thanks Rene, that seems to do the trick.

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@eric, just upgraded my QNAP TS-470 Pro (Roon Server) to latest firmware, “4.3.4.0664 Build 20180710” and the QNAP team seem to have included a newer build of ffmpeg in this release:

ffmpeg version 3.3.6 Copyright © 2000-2017 the FFmpeg developers
built with gcc 4.9.2 (Debian 4.9.2-10)

Edit: At first the issue didn’t surface, but after a second listen the crackling sounds still are sprinkled all over the music… So, the newer ffmpeg in QNAP OS didnt do any good.

I am experiencing the same issue with a Roon core running on an Ubuntu server and ffmpeg version 3.3.4-2.

Intersample overs are ugly.

Here is a comparison. The red curve is Benchmark a DAC 1 (no inter sample overs capability). The grey curve is a Benchmark DAC 3 which has extra headroom to handle inter sample overs.

Just like clipping - inter sample overs are really very ugly. A pity that almost no commercial DACs can handle inter sample overs.

Credit to Jim Austin at Stereophile for making these measurements and providing this graph.

All – Just reaching out to let you know we’ve just released an update that addresses this issue. Please update to build 339 and let us know if you have any issues.

You can read more about the update here:

We genuinely appreciate your patience here!

Kind regards,
Eric

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That did the trick! :+1:
No more crackling with Build 339 installed on the server.

Now AAC-files sound as good as… AAC-files… :wink:

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The fix worked for me as well…yay! :slight_smile:

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