Flac decoder warning

[stefano_mbp]

Hi Simon,
I often find in the Minimserver log (info mode) these warnings:
“FLACDecoder: FindSync LOST_SYNC: 5c at offset 312439 in … file name”
“FLACDecoder: FindSync LOST_SYNC: 24 at offset 305807 in … file name”
“FLACDecoder: FindSync LOST_SYNC: 0 at offset 235038 in … file name”
“FLACDecoder: FindSync LOST_SYNC: 0 at offset 278823 in … file name”
It doesn’t occurs while scanning but while browsing the library and they are always related to four tracks, always the same four.
And it occurs often but not always.
What does it mean?
MinimStreamer settings are as attached screenshot
Thanks

[simoncn]

Are you using BubbleUPnP to browse your library? If so, this might be related to the behaviour described in this post where BubbleUPnP reads audio files while browsing in some circumstances.

For a FLAC file transcoded to WAV using the built-in MinimStreamer converter, reading the transcoded WAV stream also requires reading the original FLAC file. Depending on exactly how BubbleUPnP is reading this data, it is possible that messages like this could be produced.

Please confirm whether BubbleUPnP is involved in this.

[stefano_mbp]

I’m using Lumïn app with Bubbleupnpserver that should be involved only in giving OpenHome compatibility to Lumïn app.
“Make this Media Server available in BubbleUPnP for Android and foobar2000 for Internet access” and “Create a proxy Media Server on this LAN” Bubbleupnpserver options are unchecked/disabled.
Lately I’m using sometimes JPlay for IOS app just for testing.
Anyway the issue was there before starting to use JPlay

[simoncn]

The LUMN app downloads the entire MinimServer library and stores it locally, so neither it nor your renderer should be reading transcoded WAV streams for these four files while you are browsing.

Is it possible that the messages are being produced while the LUMIN app is downloading your MinimServer library, not while you are browsing?

Alternatively, might the messages be produced while you are browsing using the "folder view" icon in the LUMIN app? I think this reads from the server, not from a local copy of the server data.

[stefano_mbp]

Following your hints I discovered that the issue occurs:
- during Lumïn library loading task (only 1 track/album for four albums)
- while playing those 4 albums (for every track of the album)

[simbun]

You can check for file corruption with:

Code:

flac -t "<filename>"

Or by using the FLAC Frontend which can be found here.
NOTE: It comes with FLAC 1.3.0 (at least the portable version does) so it might be worth updating to the latest.

[stefano_mbp]

Thanks … but I’m on Mac or Linux … Minimserver is running on Ubuntu 22.04 LTS, I’ll follow instructions from the second link

[simoncn]

It is worth checking for file corruption but the problem might have some other cause, such as a problem with the FLAC decoder used by MinimStreamer. Can you post one of these files somewhere so that I can download it and try to reproduce the problem? I can send you instructions to upload the file to my FTP server if that would be helpful.

[stefano_mbp]

Thanks Simon, I’ll send you tomorrow in pm a link to a google drive folder

[stefano_mbp]

Following Simbun suggestion I was able to repair the corrupted tracks, indeed they were, using XLD and transcoding the tracks from flac to flac, this was enough to repair them.
Now no more warnings in the log
Thanks to all