Replace ID3Tag with own-coded thing

[Wohlstand]

libID3TAG is a GPL-licensed dependency that shouldn't be. Also, it gives lots of unneeded stuff and lacks support for some other. So, on the "wip-build-polishing" here is a work on a new thing.

• Use the tag skipping base made in music_mad.c by @sezero previously
• Make parsing of ID3v1 tags (don't parse when ID3v2 or APE was successfully parsed)
• Make parsing of ID3v2.3 (specification)
• Make parsing of ID3v2.4 (specification of main structure, frames)
• Make parsing of ID3v2.2 (specification)
• Make parsing of APE tags (don't parse when ID3v2 was successfully parsed) (specification)
• Find a way to skip the Lyrics3v2 tag that appears in some MP3 files (specification)
• Find a way to skip the Lyrics3v1 tag that may appear in some MP3s (specification)
• Fix the incorrect logic of ID3v1ext (TAG+): the content of TAG+ should be added to end of ID3v1, it shouldn't replace it with self
• Prevent MPG123 to see tags, otherwise, it may spawn "Invalid frame, re-syncing" error message into stdout. Is not critical as MPG123 is smart to don't decode crap that tries to look like a frame.
• Check out for Musicmatch tag format

Example of Lyrics tag from "v22obsolete.mp3":

LYRICSBEGININD0000200ETT00034LYRIC01234567890123456789012345678000063LYRICS200

Idk where is a specification that explains it more accurate Found it at id3-org, phew...

• Various example files with various ID3 tags: ID3tag samples.zip (doesn't includes examples with APE tags yet)
• Example of ID3v1ext (TAG+): v1plus.mp3.zip and original software which can create them: speedtag351.zip
• Examples of APE tags: APEv1and2tag.samples.zip
• Lyrics3 examples: Lyrics3-samples.zip

[Wohlstand]

APEv1and2tag.samples.zip
APEv1 and v2 tag samples, hand-made via hex editor, may be incorrect.

[sezero]

https://robert.muth.org/Apetag/
https://github.com/robertmuth/apetag.git

[Wohlstand]

Oh, thanks, useful thing! I need to verify my code better...

[Wohlstand]

Okay, I re-made some tags:
APEv1and2tag.samples2.zip
And yeah, here is a possible bug that causes MPG123 to try read a APEv1 tag as a frame, therefore it says "Bad frame, going to re-sync", so, I should fix that...
(APEv1 tags still hand-made because of no wrirers available, but, it's very easy to make it: remove header, and then, replace in a footer two bytes are meaning version, and voila!)

[Wohlstand]

Okay, it's not a fault of tagger, it's a fault of music_mpg123.c as it's doesn't prevents library to access tag areas, therefore, MPG123 gets a fail to parse frame on a place of some tag. To fix this, I need to make the limitter that will don't allow mpg123 go more than given limit to avoid it see any tags.

[Wohlstand]

So, the only one minor thing is left - make skipping of "LYRICSxxxx" tags

[Wohlstand]

About Lyrics tags, after searching, I have found two specifications:

• http://id3.org/Lyrics3
• http://id3.org/Lyrics3v2

They are should be skipped

Also, @sezero , because of these lyrics tags, your MAD code can't find and skip them.

Also, some random code: jiajen/mp3edit@d4c845f

[sezero]

About Lyrics tags, after searching, I have found two specifications:

* http://id3.org/Lyrics3

* http://id3.org/Lyrics3v2

They are should be skipped

Also, @sezero , because of these lyrics tags, your MAD code can't find and skip them.

Also, some random code: jiajen/mp3edit@d4c845f

F... Is there no end to this thing??

[Wohlstand]

What do you mean? If you mean more tags, I guess, there is no more should be more than this. By a specification, looks like it's very simple algorithm to skip them, will make a thing if I get my home.

[Wohlstand]

MP3 format is a mess and therefore lots of alien tag formats ...

[sezero]

What do you mean? If you mean more tags,

Yes

[sezero]

Also, @sezero , because of these lyrics tags, your MAD code can't find and skip them.

AFAIK, libmpg123 doesn't handle those tags? Does it have issues decoding
any such mp3 files? (I don't have any such mp3 files myself.)

[Wohlstand]

Try to play my examples with APEv1, both will make mpg123 to print out a frame error

[sezero]

Try to play my examples with APEv1, both will make mpg123 to print out a frame error

I meant mp3 files with that lyrics3 thing. (And I don't know if there really any APEv1 tagged mp3s are in the wild..)

[Wohlstand]

Files with lyrics: some of files in my first samples pack, and probably, one of ID3V2.3 called as "obsolete" or may be another file, it's with a Lyrics3v2

[Wohlstand]

It also causes mpg123 to print an error

[Wohlstand]

I meant mp3 files with that lyrics3 thing. (I don't know if there really any APEv1 tagged mp3s are in the wild..)

I'll try to dig off my music collection, maybe some are? Btw, ApeV2 tags I have found in some songs of Mayumi Kojima.

[Wohlstand]

Okay, for lyrics3 tags I made a skipper and it works on my samples:
Lyrics3-samples.zip

178e5f3#diff-be03c50dd3ee1164877fb642e43ac967R481-R483

I guess there are files around in a wild with these tags to verify the work better. Lyrics3v1 tag is very simple to create by hands: it needs two marks and any random text typed between them. Lyrics3v2 is a more complex thing that can't be made easily, but, I had some samples are used it.

[sezero]

You should test against files in the wild, not by hand-crafted ones.
To that end, I'm unsure whether we should really keep the extended
ir3v1 (TAG+) support in there.

[Wohlstand]

I'm unsure whether we should really keep the extended

ir3v1 (TAG+) support in there.
The fact it exists a long time, we should support it at least to just skip.

You should test against files in the wild, not by hand-crafted ones.

I would dig around the world some of them, I bet there exist as these tags were in a standard. Lyrics tags are not for parsing: skipping only. For a MAD who is silly and won't correctly validate a frame, it's critically to skip all tags as possible to prevent a crash. MPG123 at the same time validates frames and prints out errors when finding certain frame is not a frame and something odd.

BTW: will fix your notices tomorrow.

[Wohlstand]

Updated Lytics3 samples pack: Lyrics3-samples.zip I added few "invalid" files: with broken begin tag and broken end tags to verify error handling.

[Wohlstand]

The change e7cb2d5 I made just now, should be fine:

• no more duplicated code because I using tail_size offset as a helper to allow same code read both at end and at before ID3v1.
• handling ONE OF tags: endian APE, Lyrics3, and ID3+ in a condition that ID3v1 is presented.

Can you review current state of code?

[Wohlstand]

@sezero, okay, just now I have found a BUNCH of files with a Lyrics3 tag are taken from the wild: I have found on my server's depths a ton of MP3 musics of my friend, and I downloaded all of them. I did a scan of them for some tags by grep, and I have found 11 songs are has this tag. I'll email them to you.

[Wohlstand]

Oh, wow, one of them contains TWO Lyrics3v2 tag entries 🤔

[Wohlstand]

Okay, I took a multi-tag (two Lyrics3 tags in the same file) from a wild file and I have updated Lyrics3 samples: Lyrics3-samples.zip

[Wohlstand]

A little test for some players: APEv2mixLyrics3.zip I made a mixture of APE2 and Lyrics3, and VLC, Xplayer and Rhythmbox won't show tag of mixture files, but showing a tag of a normal APE tag. It's a confirmation of a think that these tags can't be used together in a same file as they are breaking their specification: each of these tags should be used before ID3v2 or at end of the file.

[sezero]

Ok. Give me some time to mess with this mess.

[Wohlstand]

Ok, I'll don't do anything here right now I think, work/research as you need. 😉

[Wohlstand]

• TAG+ example made with digged-up SpeedTAG software that you have mentioned in a email v1plus.mp3.zip
• SpeedTAG software itself http://download.dubroom.org/software/speedtag351.zip (attaching it here for just in a case: speedtag351.zip), it needs Windows 98 for a best experience. Works in Wine perfectly. Idk how it works on modern Windows, no guarantee it will work correctly.

[Wohlstand]

Okay, while worked on ID3v1ext, I have found a minor bug in ID3v1 itself (last character losts) which I have been fixed:

[Wohlstand]

Okay, all necessary tag formats are working fine, so, the issue has been completed!

[sezero]

Musicmatch tag (noticed while browsing the following page):
https://www.codeproject.com/Articles/8295/MPEG-Audio-Frame-Header#AddTags

A documentation (and a LGPL implementation) can be found in id3lib:
https://sourceforge.net/projects/id3lib/

Don't know if worth supporting

[Wohlstand]

Musicmatch tag (noticed while browsing the following page):

Never heard about this tag format...
Looks like my nightmare dream has been predicated me another work on one another tag format. and:

F... Is there no end to this thing??

your quote about Lyrics3 you didn't knew, I would to say same about Musicmatch tag I didn't knew

Will check out some... Also, I'll try to check my MP3 tons for a hope to find this tag in a wild

[sezero]

Useful archive to test your parsing code:
https://github.com/JamesHeinrich/getID3-testfiles

[Wohlstand]

Useful archive to test your parsing code:
https://github.com/JamesHeinrich/getID3-testfiles

Looks useful, thanks 🦊

[Wohlstand]

Inside of an archive I have found this text file:
musicmatch.txt

[Wohlstand]

Yeah, btw, in that getID3 the sample doesn't contains the Musicmatch tag example, or I should check it more careful, right now I gonna to sleep, will check some tomorrow.

[Wohlstand]

Okay, I have found one wild example, I have sent it to you 😉
I'll work on this on my end later, right now I am tired and I gonna to sleep.

[sezero]

The MusicMatch tag skip support is in mainstream, looks fair for now.
Having more mp3 files to test would be really good.

Closing.

[sezero]

Attaching the MusicMatch tag extracted from the mp3 you sent to me.
We need more mp3 files with MusicMatch tags.

musicmatch.tag.zip

[Wohlstand]

Possibly, it's existing in some other MP3 files... I should to grep them...

[Wohlstand]

Okay, just now I have checked more files in my server, and it's no more Musicmatch samples I have found...