ID3 tags in FLAC files.

stf92 · 01-18-2012, 01:39 AM

Hi: I have a set of FLAC files which includes a .nfo file saying:

Tags.................: ID3 v1.1, ID3 v2.3VorbisComment

I guess (wikipedia has a 24-hr blackout right now) each of the FLAC files of the set contains info about the performer, orchestra, and so on. But does the FLAC format support ID3 tags, if any tag at all? Because in the negative case, I would not bother to begin investigating how to extract the info.

EDIT
I ran 'metaflac --list foo.flac' and a part of the output was this:

Code:

METADATA block #2
  type: 4 (VORBIS_COMMENT)
  is last: false
  length: 172
  vendor string: reference libFLAC 1.2.1 20070917
  comments: 7
    comment[0]: ARTIST=Unknown Artist
    comment[1]: TITLE=01. Kyrie - Gloria
    comment[2]: ALBUM=Unknown Title
    comment[3]: DATE=
    comment[4]: TRACKNUMBER=01
    comment[5]: GENRE=
    comment[6]: COMMENT=Track 1
METADATA block #3
  type: 1 (PADDING)
  is last: true
  length: 8192

Notice how the name 'VorbisComment' in the line at the beginning of this post reappears in this metadata block (VORBIS_COMMENT). Still, I have no right to think these metadata blocks are the ID3 tags mentioned in the .nfo file.

acid_kewpie · 01-18-2012, 03:50 AM

As I understand it, FLAC does not support ID3 in any way. It is part of an MP3 file only. FLAC tags are supported, which are, as you can see there, identical to Vorbis Tags, but they technically are not ID3 tags at all. You can naturally coalesce the data between the different comment mechanisms though.

stf92 · 01-18-2012, 04:42 AM

Thanks. I may add that one of the files is a .MD5 file. The file command, when run on it says

Code:

semoi@darkstar:/hdaal/mozart/Mozart Mass in C minor$ file 00.Wolfgang\ Amadeus\ Mozart.MD5 
00.Wolfgang Amadeus Mozart.MD5: MPEG ADTS, layer I, v1,  96 kBits, 32 kHz, Stereo
semoi@darkstar:/hdaal/mozart/Mozart Mass in C minor$

I think the file command guessed the wrong way. The file has size = 2.3K. But all MD5 files I have ever seen are ascii files. This is even more mysterious to me. Nevertheless, your post has made me walk the first step in the way to uncover it. Perhaps the explanation is simple: the person who authored the FLAC files had previously made MP3 files and made a mess of it all.

EDIT
This could help me clarify the mess. There are three times asociated with a file: atime, mtime, ctime.

Code:

    atime         time of last access
    mtime         time of last modification
    ctime         time of last status change

Which of these is shown by 'ls -l'? I'm not sure I'm interpreting ls manual correctly.

cascade9 · 01-19-2012, 06:35 AM

@ stf92- tried checking the MD5 checksum manually, rather than running it through a script?

I would guerss that whoever ripped the .flac files took a 'everything, including the kitchen sink' approach. ID3 v1.X, v2.X, and vorbis comments? Rendundant. Md5 checksum? Almost useless. Whoever ripped the file/files either doesnt know about the internal checksumming (better than MD5 in all ways IMO) or uploaded it to a site that requires ID3tags and MD5 checksumming, even in cases where it isnt needed. Seen it happen before, and I'll see it happen again.....

Quote:

Originally Posted by acid_kewpie

As I understand it, FLAC does not support ID3 in any way. It is part of an MP3 file only. FLAC tags are supported, which are, as you can see there, identical to Vorbis Tags, but they technically are not ID3 tags at all. You can naturally coalesce the data between the different comment mechanisms though.

Depends on what you mean by 'supported'.

Flac files can be tagged with ID3 tags. It can cause problems with some decoders/players, and IMO there isnt any reason to use ID3 tags with flac, apart from album art.

Jeebizz · 01-19-2012, 10:25 AM

Quote:

Originally Posted by cascade9

Flac files can be tagged with ID3 tags. It can cause problems with some decoders/players, and IMO there isnt any reason to use ID3 tags with flac, apart from album art.

Files encoded in FLAC these days do not even need ID3 for album art, they shouldn't. I have always had album art displayed while listening to music encoded in FLAC. Just make sure you have a cover.jpg file in the directory and you're good.

David the H. · 01-19-2012, 11:17 AM

id3 tags can be theoretically added to just about anything, as it's just a block of metadata tacked onto the end of the file. Some encoders decided to add id3 tags to flac files in the early days of the codec, before the flac comment format was finalized, and even now you'll still sometimes find ones with them.

Unfortunately most player and transcoding programs choke in some way when they find an id3-included flac file, so they need to be removed/converted to flac format first.

I've found that the easytag tag editor is one of the best ways to deal with these. Turn off the "id3 for flac" setting in the preferences, and it will rewrite the data into flac comments.

stf92 · 01-19-2012, 02:03 PM

How interesting.

The last track of certain audio CD (CDDA) originated from a set of FLAC files, is not seen by some players but is visible for some others. I guess, from your remark,

Quote:

Unfortunately most player and transcoding programs choke in some way when they find an id3-included flac file, so they need to be removed/converted to flac format first.

that there was some trouble in the transcoding stage. Getting this easytag may therefore be a solution. The set of FLAC files I mentioned above and the "invisibility" issue is what made get the set of FLAC files one of whose metadata blocks is shown in post #1. But only to fall into the metadata issue!

@cascade9:
but when did you see an MD5 file which was not an ascii file? I can't understand who generated the file. And of course, the file command could never say a binary file is an MD5 file; its confusion is understandable.

I think this filename extension is the result of the uploader or I having renamed the file.

cascade9 · 01-22-2012, 12:46 AM

Quote:

Originally Posted by Jeebizz

Files encoded in FLAC these days do not even need ID3 for album art, they shouldn't. I have always had album art displayed while listening to music encoded in FLAC. Just make sure you have a cover.jpg file in the directory and you're good.

That works for a lot of the computer media players, but not with most portable media players. Not that adding an ID3 v2.X tag with album art will work with most portable media players anyway.......

As an aside, I _hate_ 'cover.jpeg'. I always use 'artist-album-XXXxXXX'(eg, 'Miserylab-From.Which.No.Light.Escapes-485x480.png'). I also prefer .png if I can find the album art in that format.

Quote:

Originally Posted by stf92

How interesting.

The last track of certain audio CD (CDDA) originated from a set of FLAC files, is not seen by some players but is visible for some others. I guess, from your remark,

that there was some trouble in the transcoding stage. Getting this easytag may therefore be a solution. The set of FLAC files I mentioned above and the "invisibility" issue is what made get the set of FLAC files one of whose metadata blocks is shown in post #1. But only to fall into the metadata issue!

@cascade9:
but when did you see an MD5 file which was not an ascii file? I can't understand who generated the file. And of course, the file command could never say a binary file is an MD5 file; its confusion is understandable.

I think this filename extension is the result of the uploader or I having renamed the file.

I'm fairly sure I've seen a binary MD5 checksum before. Been a long time since it happened, and it was only once though.

What other files are there? I'd expect a .log file of some description if you've got .md5 and .nfo files.

It might be a good idea to try one of the 'lossless testing' programs,. They can give you a good indication if the files are lossless or transcoded from a lossy source. No point keeping some bunch of 'lossless' files if they are just transcoded from MP3 320/VBR V0, etc..

totedati · 12-13-2013, 08:12 AM

in linux is actually simple to repair id3 tainted flacs! first strange thing in the linux world is that id3 tagged flacs will not bite you in any way until you try to use oggenc! you can play the flacs just fine, you can tag it in programs like kid3-qt and vorbis tags will coexist with id3 tags! ugh! ... commands like

Code:

flac -t music.flac

or

Code:

flac -t music.flac

will not give you any hint that is something wrong with you flacs! then you will try something like

Code:

oggenc --utf8 -q 4 music.flac

and bang!

Code:

ERROR: Input file "music.flac" is not a supported format

WHAT!?

and finally, you do, at years distance of the original ripping movements, that final check you forgot to do:

Code:

file *.flac
music.flac:  Audio file with ID3 version 2.3.0, unsynchronized frames, contains: FLAC audio bitstream data, 16 bit, stereo, 44.1 kHz, 13427568 samples

WTF!?

from where is this alien bug landed on my hdd!? and what to do now? i want my flacs back! well, in linux world is simple:

Code:

for input in $(find . -maxdepth 1 -type f -name '*.flac'); \
do temp=$(basename $input .flac); \
metaflac --export-tags-to=$temp.metaflac $input; \
id3v2 -D $input; \
metaflac --dont-use-padding --remove-all $input; \
metaflac --import-tags-from=$temp.metaflac $input; \
rm -v $temp.metaflac; \
done

and voila, all you flacs is back and sane:

Code:

file *.flac
music.flac:  FLAC audio bitstream data, 16 bit, stereo, 44.1 kHz, 13427568 samples

caveats emperors:

Code:

rm -v $temp.metaflac; \

is dangerous, use only if my bash programming skills look strong enough, or else is safe to edit my code snipets and delete this line

Code:

metaflac --export-tags-to

export only metadata tags, embeded pictures and imported cuesheets will be lost

stf92 · 12-13-2013, 08:35 AM

Thank you, totedati.

dugan · 12-13-2013, 11:30 AM

I only skimmed the thread, but Puddletag is my favorite tagger and it works transparently with FLACs.

totedati · 12-14-2013, 01:16 PM

o yeah, and the chances for puddletag to work also very transparently and quietly with Audio file with ID3 version 2.3.0, unsynchronized frames, contains: FLAC audio bitstream data, 16 bit, stereo, 44.1 kH is very high!

i make a little correction to my script, original solution can end in flacs with doubled vorbis tags because id3v2 strip only id3 tags

frankbell · 12-14-2013, 09:28 PM

There was a podcast last week about metadata in audio files at Hacker Public Radio. It might help.

273 · 12-14-2013, 09:34 PM

I've been using easytag for a while to add titles, author... and album art to FLAC files and my portable media player is fine with them too.