ID3v2 tags gets wiped out

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2COOL
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ID3v2 tags gets wiped out

Post by 2COOL » Thu Oct 02, 2008 8:06 pm

Recently I have been working with my tags in MP3, especially ID3v2 tags. The problem is that it gets wiped out everytime I edit & save the song and I have to input back in again. I just need to have my album art covers due to me having a IPhone. Anways, I didn't see anything in Preferences or Project to prevent my tags being affected.

Using 1.2.6

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Re: ID3v2 tags gets wiped out

Post by steve » Fri Oct 03, 2008 1:15 pm

Try using Audacity 1.3.5 and make sure you start a new project each time you want to edit a file.
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1.3.5 and ID3v2 tags

Post by 2COOL » Fri Oct 03, 2008 7:21 pm

Discussion on this subject has been detoured to this forum as I am now using v1.3.5beta. I hope I'm not cross-posting.

Here is a more detailed post to prove my point that my pre ID3v2 tags are being wiped out in the area of file before Audacity applies it's input default template.

Image

This is what I get when looking at the Audacity's MetaData Editor. It shows a year 2008 input. But looking at the AFTER results, the Year is blank.
Image

Other notes are that Zortam MP3 also writes in ID3v1 tags but Audacity writes that out too. Ideally here is that I Audacity to touch to overwrite the area that the tags in written in. I don't know if there is a standard of where that tag writing area lies withing the MP3 file (Edit: Looking with a hex editer, it looks like it's in the beginning of the file) or how the order of tag info should be written.

I can always do a post edit with my Zortam prog but it seems that I'm doing extra work. Wish Audacity could detect the tag writing area and bypass in general. I wonder if there some start bit/bytes that say where the tags begin and end? May have to research later when I have the time...

Update: Found this?
id3v2.4.0-structure
About id3v2.4.0-frames (See Section 4.14. Attached picture)
Relevant stuff: UltraID3Lib
For MP3 files, iTunes writes tags in ID3v2.2 using UCS-2 encoding by default, but converting them to ID3v2.3 (UCS-2 encoding) and ID3v2.4 (which uses UTF-8 encoding) is possible via its "Advanced" > "Convert ID3 Tags" toolbar menu. If both ID3v2.x and ID3v1.x tags are in a file, iTunes ignores the ID3v1.x tags.
from Wikipedia ITunes
Last edited by 2COOL on Fri Oct 03, 2008 9:16 pm, edited 7 times in total.

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Re: ID3v2 tags gets wiped out

Post by 2COOL » Fri Oct 03, 2008 7:24 pm

@stevethefiddle

Thanks for the reply. I used 1.3.5. and got the same results. Decided to post that separate test in the 1.3 Discussion forum.

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Re: ID3v2 tags gets wiped out

Post by steve » Fri Oct 03, 2008 8:33 pm

To make the discussion easier to follow I've merged the two topics.

The ID3v2 tags aren't getting "wiped out", but you are loosing some of the data from them - namely the Year and the cover art.
The trouble is that ID3v2 tags are not really a standard. The document you refer to describes it as "an informal standard". Even with official, recognised formal standards, it is difficult to get everyone to play ball (for example, see how Microsoft blatantly disregard W3C standards for HTML and CSS). For "informal standards" , in the words of Captain Barbossa, "think of it more as a guideline".

One of the least standard parts of the ID3v2 format is cover art support. Until the issue is clarified by a formal standard, there is little point the Audacity developers spending a great deal of time trying to fully support it, as they can write it to support one products version of id3v2, but it will fall foul of another products version, and there is no guarantee that the standard will be implemented tomorrow in the same way that it is implemented today. It's been many years since 1d3v2 was first put forward, but still there is no real standard - hopefully it will be standardised one day, but by then people will be asking for an informal id3v3 to be supported.
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Re: ID3v2 tags gets wiped out

Post by 2COOL » Fri Oct 03, 2008 10:10 pm

@stevethefiddle

Thanks for your reply. Yes, there is no formal standards to "get everyone to play ball" :(

I'm not an expert of the mp3 structure but I do believe in reverse engineering. It seems Audacity knows where the start of the audio stream is (audio header?). If so, take a snapshot of the bytes before it (existing ID3 tag bytes) and pasting it in front of newly saved mp3. Sound logical but I think there is more to it. I just wished Audacity had the option to bypass, not read/write the existingID3 tag section, and just work on the audio stream part.

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