Tag Problem Transcoding FLAC --> MP3 --> iTunes

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bkburns
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Tag Problem Transcoding FLAC --> MP3 --> iTunes

Post by bkburns » Tue Sep 05, 2006 5:01 am

I am having some tagging difficultings when I do the following:

1.) Rip via Max to flac format. Name, Artist, Year, Genre, Track X of Y, Disk A of B, and comments.

2.) The tags show properly when using Tag to review and edit. Cog plays the files properly and thows the tags properly in the info screen.

3.) I use Max to transcode the Flac's to MP3's using the transparent settings.

4.) The MP3's show tags properly when playing in Cog.

However, Step 5 causes me heartache:

5.) I drag the resulting transcoded MP3's into a new playlist in iTunes.
- The trackname is the filename.
- There are no Disc or Track numbers.
- There are no comments
- Genre, Artist, and Album are correct.

I do not think I have changes any settings on this relatively new install of 0.6.1 of Max. It is running on an Intel Mac Mini on 10.4.7 of OSX. I *think* I have the same problem on my PowerPC Powerbook.

Thoughts?

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sbooth
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Post by sbooth » Tue Sep 05, 2006 6:01 am

There is a chance that the COMM frames Max generates when transcoding have an invalid length. Do you have any id3 utilities (or even a hex editor like 0xED) available to inspect the file so we can try and confirm this?

bkburns
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Post by bkburns » Wed Sep 06, 2006 12:56 am

1.) I am not quite the geek needed to know what I am looking for. I have installed 0xED. What do I need to look for?

2.) Alternately, suggest an ID3 tool and I will install that and output whatever results you want.

3.) Alternately, I can post a flac and the transcoded MP3 for you to look at on the web.

Your call. I await your command :-)

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sbooth
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Post by sbooth » Wed Sep 06, 2006 2:29 am

Cool, since you have 0xED, that will be the easiest.

For some background, an ID3v2 frame should have a 10 byte header; four bytes for the frame ID, four bytes for the size of the frame, and two flag bytes. I suspect that TagLib is setting the incorrect size for strings that contain newlines.

I am able to duplicate the behavior you describe with Max 0.6.1. Here is what an offending file looks like in 0xED:

Image

You can see the part that is highlighted is the first 8 bytes of the comment (COMM) frame. The size is incorrectly set as 0x138, which seems to be giving iTunes issues. Most tag readers have no problem with this, so I'm not sure why iTunes chokes, but in any case, the tag seems to be corrupt.

Can you open the offending file with 0xED, take a screenshot, and then post it so I can try to determine if the tags are malformed?

bkburns
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Location: Memphis, TN

Post by bkburns » Wed Sep 06, 2006 3:20 am

Screenshot from 0xed:

Image

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sbooth
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Post by sbooth » Wed Sep 06, 2006 4:16 am

That id3 tag looks suspect to me; it seems like TagLib is adding a spurious 1 in the length for the COMM field when a newline is present.

I've downloaded the svn version of TagLib, and I will give it a shot and see if it makes a difference.

bkburns
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Location: Memphis, TN

Post by bkburns » Wed Sep 06, 2006 4:34 am

Thanks!!!

bkburns
Posts: 16
Joined: Tue Jan 31, 2006 6:25 am
Location: Memphis, TN

Post by bkburns » Wed Sep 06, 2006 4:52 am

I think you are correct, if I take a source flac that gave me errors before and remove the contents of the comment tag, it transcodes and imports fine.

However, some of the files that have the problem do not have a newline character showing in the comments field, at least when I view them in Tag. All that is there is the Max generated encoder settings. Everything appears to be on one line. I have not narrowed it down any further than that.

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