Skip to main content

Notice

Please note that most of the software linked on this forum is likely to be safe to use. If you are unsure, feel free to ask in the relevant topics, or send a private message to an administrator or moderator. To help curb the problems of false positives, or in the event that you do find actual malware, you can contribute through the article linked here.
Topic: Does retagging FLAC albums can affect the integrity of FLAC files? (Read 2680 times) previous topic - next topic
0 Members and 1 Guest are viewing this topic.

Does retagging FLAC albums can affect the integrity of FLAC files?

I have about 100 albums I ripped months ago and I would like to make some changes at the genres of the albums. I was wondering if modifying the metadata of the FLAC files can affect the integrity of the FLAC files. The date stamp of the files after retagging will change to the current date that's for sure, but other than that can the audio of the FLAC get affected in any way?

Re: Does retagging FLAC albums can affect the integrity of FLAC files?

Reply #1
No, the audio won't be touched.

...I have heard of cases where ID3 tags were added to a FLAC (they are supposed to use Vorbis comments) and then some software couldn't open or play the FLAC.    I'm not sure how that was done because good tagging software shouldn't do that.

P.S.
Audacity can't write a tag without re-writing the whole file so there's a possibility of accidently adding dither or otherwise altering the audio.   So, don't use Audacity if all you want to do is add or edit metadata.

Re: Does retagging FLAC albums can affect the integrity of FLAC files?

Reply #2
I'm using Kid3Qt in Linux. It's a simple software made for the KDE desktop environment but it works in GNOME as well.
I just edit the genre field and press the save button. I don't think it changes anything else. It's a very simple software with no side effects.
I think Musicbrainz Picard do some stuff in the background like you mentioned with ID3 tags, but as far as I know it removes them from FLAC during save, not add them.

Re: Does retagging FLAC albums can affect the integrity of FLAC files?

Reply #3
The date stamp of the files after retagging will change to the current date that's for sure
Depends on which application you use.
https://help.mp3tag.de/options_tags.html
And foobar2000 can as well, but you need to go into the "Advanced" preferences.

Edit: Ouch. Didn't see you were using *n*x.

Re: Does retagging FLAC albums can affect the integrity of FLAC files?

Reply #4
Wow, Porcus, you are the best!! I think I found that option in Kid3Qt as well. There is a "preserve timestamp" option in the settings unchecked. I should check that then.

Re: Does retagging FLAC albums can affect the integrity of FLAC files?

Reply #5
Wow, Porcus, you are the best!! I think I found that option in Kid3Qt as well. There is a "preserve timestamp" option in the settings unchecked. I should check that then.

Unless you're sure that your backup and music server software don't rely on the modified date to be able to identify changed files (which they probably do) I'd leave it unchecked.

Re: Does retagging FLAC albums can affect the integrity of FLAC files?

Reply #6
Good point. Some music player/library managers can force rescan and re-read new tags. If not, one might have to discard the library and redefine it.
Not unlikely that can be done by renaming a folder back and forth ... ?

Re: Does retagging FLAC albums can affect the integrity of FLAC files?

Reply #7
Often a FLAC is created with a padding block in the header.
As long as the edits of the meta data fits in, the file is not rewritten.
If it doesn't the file must be re-written.
Proper tagging software won't alter the audio part. The MD5 also remains the same so you can always test the audio part
FLAC –t FileToTest.FLAC
TheWellTemperedComputer.com

Re: Does retagging FLAC albums can affect the integrity of FLAC files?

Reply #8
Yes, I'm using rsync but I'm going to upgrade to a new hard drive so I will re-upload all the albums to it again. In this situation keeping the old date won't be an issue, as the new HDD will be empty when I run rsync. The rsync software will want to push them all when it will notice the folders aren't present on the new drive. But yes, for future edits that's a good thing to consider.

Re: Does retagging FLAC albums can affect the integrity of FLAC files?

Reply #9
Often a FLAC is created with a padding block in the header.
As long as the edits of the meta data fits in, the file is not rewritten.
If it doesn't the file must be re-written.
Proper tagging software won't alter the audio part. The MD5 also remains the same so you can always test the audio part
FLAC –t FileToTest.FLAC

When a metadata field is changed is the data in the padding block overwritten? just asking because when I had covers embedded and removed the cover, the cover disappeard in the media playing software but it was still present in the padding taking up space unless I ran these two commands, which brought back the file sizes as they were before the covers were added:

     metaflac --remove --block-type=PICTURE,PADDING --dont-use-padding *.flac
     metaflac --remove-tag=COVERART  --dont-use-padding *.flac

I think that's not the case with regular text data. I just update existing text fields like genre and do not add additional ones.

Re: Does retagging FLAC albums can affect the integrity of FLAC files?

Reply #10
There is a separate space for pictures.
Full detail can be found here: https://xiph.org/flac/format.html
TheWellTemperedComputer.com

Re: Does retagging FLAC albums can affect the integrity of FLAC files?

Reply #11
The padding block is overwritten with zeros (cleared) by most software when metadata is changed, and it is extended if the new metadata is shorter. Padding is never removed until you invoke a special command for it. This is by design and allows to remove the cover and add another cover in its place or extend the text data quickly without rewriting the file.

When you edit the text data, the padding is still there but it is smaller. In a file with a large cover art, editing text data causes a noticeable delay in Foobar because it accesses the cover data too.

Re: Does retagging FLAC albums can affect the integrity of FLAC files?

Reply #12
Yes, I'm using rsync but I'm going to upgrade to a new hard drive so I will re-upload all the albums to it again. In this situation keeping the old date won't be an issue, as the new HDD will be empty when I run rsync. The rsync software will want to push them all when it will notice the folders aren't present on the new drive. But yes, for future edits that's a good thing to consider.

Be aware of the fact that when using rsync to sync incremental changes of your library on a later moment, you probably need to use the '-c' option as well if you have edited tags only and leaves the time-stamp unchanged. A regular 'rsync -zavh' often won't pick up the changes in that case.