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Topic: Unable to extract MP3 info< Next Oldest | Next Newest >
Patrick
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Posted: June 03 2003,06:50
Hello.

I use Windows Media Player 9 for my mp3s. I have noticed that occasionally a random mp3 will not play and produce an error. The same mp3 will play normally in my cdr writing program (Feurio) and Winamp.

I do not know why this is. All the tracks from the same "rip" will play fine (in WMP9) except one for example. MP3 Tag Studio says "Unable to extract MP3 info" when I select these files and gives a similar error when I try to repair them. They are not always VBR files, most are actually CBR.

Removing all the tags and frames etc. does not seem to help any. Its strange because MP3 Tag Studio can always read the tags of these files, it just cant get the basic file info like length/bitrate/flags etc.

If you would like I can send one of these files for you to look at.

Thank you for any help. I have my entire collection organized quite nicely in WMP9 now but these dozen or so bad files are frustrating. I will say that I can decode them to wave files and then re-encode them but this is time consuming and of course doesnt help explain what was wrong in the first place,
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Magnus Brading
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Posted: June 03 2003,12:16
Sure, send me a sample and I'll take a look at it.

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Patrick
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Posted: June 03 2003,14:03
Lovely! I have sent you an email.

Thank you very much,

Patrick
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Magnus Brading
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Posted: June 03 2003,15:57
I've looked at the file, and the problem is that it contains extensive amounts of junk data between the ID3v2 tag and the mp3 data (80271 bytes of null-characters to be correct). This data has most likely been added by a faulty encoder or tagger program.

You cannot automatically repair that much junk data, but here's how to manually repair the file:

1.
Use a hex-edior to patch the bytes at offset 0x7-0x9 to the values 04 76 4B. What's really happening is that I'm patching the ID3v2 tag size field to incorporate the trash data into the tag instead of the mp3 sound data.

2.
Start Mp3/Tag Studio (the file will now be readable) and choose to remove the tag.

3.
Perform a repair of the type "Remove junk data before first mp3 frame" in Mp3/Tag Studio on the file.

4.
Create a new ID3v2 tag based on the data in the remaining ID3v1 tag (you can do it e.g. with the browse tool or the "Direct tag manipulation" tool).

The file is now fully repaired.

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Patrick
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Posted: June 03 2003,17:36
Wow! I have no idea how that happened!

Now I guess I cant patch the same offsets on all the bad files? Is there a way to tell where the start of the mp3 audio is? I really dont care about losing the tags I can make those again.

ps. I used "MP3 Filename Formatter" to tag all my mp3s. I guess we can blame that lol.

Thanks for the info though, I have a hex editor and a bit of free time.
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Magnus Brading
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Posted: June 03 2003,19:18
Most of the junk data seemed to be zero-bytes, even though it had some non-null junk data after it too. I would think that the following generic procedure would fix practically all the files anyway:

1.
Remove the ID3v2 tag with Mp3/Tag Studio (without the manual patching).

2.
Using a capable hex-editor, cut-off all zero-bytes in the beginning of the file.

3.
Perform a "Remove junk data before first mp3 frame" in Mp3/Tag Studio.

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Patrick
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Posted: June 03 2003,23:06
http://forums.somethingawful.com/showthr....7778000

Look what you started :-p.

I found one mp3 with SIX megabytes of zeros! Over half the file was ZEROS! I have no idea how that ever happened!
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Magnus Brading
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Posted: June 04 2003,00:17
:D

Even funnier, tell them that they can actually use Mp3/Tag Studio to auto-run that single-file fix program on all the files, and don't have to bother with the programming themselves. :)

Simply use the settings in the "file menu --> settings... --> extended tool settings --> name and tag tools --> browse/edit tags" to configure it, and then easily access it from the shell-extension (explorer right-click menu).

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